MSC 1993 World Users' Conference
Proceedings
The conference proceedings for the
1993 World Users' Conference are now available on-line in Adobe Acrobat
PDF format. (The Adobe Acrobat Reader software is available for free download
from Adobe's web site at www.adobe.com).
When printed, these PDF files will produce a better quality image than
the one shown on your computer screen. All papers have been categorized
by topic.
Categories
Analysis
Methods
- COUPLING
OF MSC/NASTRAN AND BEM STRUCTURAL MATRICES (Acrobat
702KB) #0493
- M. J. MeNamee -- United
Technologies Corporation
- K. L. Leung -- United
Technologies Corporation
- P. B. Zavareh -- United
Technologies Corporation
ABSTRACT: Accurate
stress analysis using a combination of the Finite Element Method (FEM) and
the Boundary Element Method (BEM) is achieved by coupling MSC/NASTRAN with
symmetric BEM structural matrices through the use of the external superelement
technique. A DMAP procedure is developed to incorporate the symmetric stiffness
matrix derived by the BEM into the global stiffness matrix generated by MSC/NASTRAN.
This coupled MSC/NASTRAN BEM analysis procedure provides a way to exploit
the versatility of MSC/NASTRAN in handling wide classes of engineering problems,
including those involving nonlinearity and inhomogeneity, while maintaining
the accuracy of the BEM in areas of crack and stress concentration. Several
analysis examples are given to illustrate the usefulness of the proposed technique.
- EXACT CALCULATION
OF MINIMUM MARGIN OF SAFETY FOR FREQUENCY RESPONSE ANALYSIS STRESS RESULTS
USING YIELDING OR FAILURE THEORIES (Acrobat 465KB) #0593
- Françis Charron -- Université
de Sherbrooke
ABSTRACT: In
static analysis, the calculation of minimum margins of safety using yielding
(Von Mises,...) or failure theories (instability for honeycomb structure,...)
requires all stress components (3D case : sigma xx, sigma yy, sigma zz,
tau xy, tau xz, tau yz ; both magnitude and sign) for a specific element.
In frequency response analysis, the stress component magnitude and sign
are functions of the reference phase angle and the phase angle of each of
the various stress components. When the phase angle difference between the
various stress components is almost equal to 0 or 180 degrees, the calculation
of the minimum margin of safety is simple. However, in the general case,
the minimum margin of safety will be dependent upon both the reference phase
angle, as well as the phase angle of each of the various stress components.
This paper describes a method used for the calculation of the exact
minimum margin of safety for the general case. For the
2D and 1D elements, the exact minimum margin of safety is evaluated at the
lower and upper fibers of the element where the flexural stress is maximum
and the transverse shear stress contribution is equal to zero. The calculation
of the exact minimum margin of safety is done by a general stress processor
using the MSC/NASTRAN OUTPUT2 file.
- MSC/NASTRAN
SHELL AND SOLID ELEMENT MESH REQUIREMENTS IN THE VICINITY OF A CIRCULAR HOLE
STRESS CONCENTRATION (Acrobat
1.04MB) #0393
- Robert P. Thacker, Jr.
-- Boeing Computer Support Services
ABSTRACT: This
paper takes a look at the mesh density requirements when the geometry is
a flat plate, has a circular hole, and is subjected to a uniform tension
along two opposite edges. The program to be used is MSC/NASTRAN, Version
67, a finite element program from the MSC.Software Corporation. The elements
used are the 8 node parabolic shell, 8 node linear solid, and the 20 node
parabolic solid. The objective is to determine the number of elements, in
the radial and angular directions, to achieve an accuracy in deflection
and in stress of less than 2% error. The mesh density to achieve the 2%
error criteria will be checked on all nodes along 3 straight lines, at angles
0, 45, and 90 degrees, from the hole to the edge of the plate and also all
nodes around the circumference of the hole.
- PARALLEL
PROCESSING IN MSC/NASTRAN (Acrobat 500KB) #0293
- Dr. Louis Komzsik --
The MSC.Software Corporation
ABSTRACT: The MSC.Software
Corporation has been researching parallel computational methods and evaluating
their applicability to its products since 1985. Limited parallelism has
been offered in various MSC/NASTRAN products, mainly on supercomputers,
since 1987. Presently, there are 5 major computer platforms where shared
memory parallel execution is supported.
The paper will discuss some of
the technical details of the shared memory parallel methodology and explore
the limitations of parallel speedup on the current parallel environments
using MSC/NASTRAN. Results of the leading parallel applications will be
shown on a moderate number of processors. Specifically, a 4 fold parallel
speedup on 16 CPUs analyzing a large automobile industry job will be demonstrated.
The results of investigations
on using a distributed memory methodology (applied in the massively parallel
computers) will also be discussed. The main strategic aspect of Lagrange
multiplier-based solution sequences and the topic of supermodules will be
briefly addressed.
Applications
- COMPUTATION
OF STRESS INTENSITY FACTORS USING MSC/PROBE VERSION 5 (Acrobat 1.16MB)
#7693
- John E. Schiermeier
-- The MSC.Software Corporation
ABSTRACT: In
fracture mechanics, the stress intensity factor is used to determine whether
a crack will run, possibly causing catastrophic failure or arrest. Typically,
this value can be computed from the stress or displacement fields around the
crack tip, either by hand or by numerical methods, and then compared with
empirical data.
MSC/PROBE-PLANAR has
long had two methods of computing Mode l and II stress intensity factors which
take advantage of the p-version, the contour integral and cutoff function
methods, as well as the standard energy release rate. In Version 5, MSC/PROBE-SOLID
has incorporated singularity elements to model exactly the displacement field
for a closed crack, and the crack-opening displacement (COD) method to automatically
compute Mode I, II, and III stress intensity factors. Combined with the automatic
p-adaptivity, accurate and reliable factors may be computed for fully three-dimensional
problems in an efficient manner.
- This paper provides
an explanation of the stress intensity factors and the methods used to compute
them. Sample problems are run, using MSC/XL V3B as the pre- and postprocessor,
and the computed stress intensity factors are compared with theoretical results
where available.
- DESIGN AND
ANALYSIS OF CORIOLIS MASS FLOWMETERS USING MSC/NASTRAN (Acrobat 833KB)
#5493
- C. P. Stack -- Micro Motion, Inc.
- T. J. Cunningham -- Micro Motion,
Inc.
ABSTRACT: A
Coriolis mass flowmeter measures mass flow directly by vibrating a fluid-conveying
pipe at resonance. Design of these meters was facilitated by solving the equations
of motion via the finite element method. A complex eigenvalue analysis (SOL107)
was necessary due to the presence of the Coriolis force terms in the damping
matrix. Performance parameters of the meter can be predicted from the complex
eigenvectors and were found to match experimentally determined values to within
five percent.
- Since vibration occurs
during Coriolis meter operation, low stress designs must be used to preclude
fatigue failure. This analysis was also performed using MSC/NASTRAN.
- DETERMINING
TUBE STRESS FROM CBEND ELEMENT FORCES AND MOMENTS (Acrobat 740KB) #6493
- Raymond N. Frick, Ph.D., P.E.
-- Pratt & Whitney
- ABSTRACT: MSC/NASTRAN is
used extensively in the design of external tubing for turbo-fan aircraft engines
at Pratt & Whitney. It accurately calculates the stress of tubes under
pressure, thermal, and case displacements and also natural frequencies. Many
of the external tubes are small diameter (under 3/4 inch) and are part of
a complex tube system. The most effective element type for these tubes
is a "beam" element such as the CBEND. A complex small diameter
tube system modeled with CBEND elements is very efficient compared with the
same system modeled with CQUAD4 plate elements. However, while the MSC/NASTRAN
CBEND element uses the ASME Code equations to account for the ovalization
of the tube in the bends, the stress output is not complete. The in-plane
and out-of-plane bending moments are not combined while the torque stress
and the hoop stress are ignored. Therefore, the correct principal stresses
are not determined. Pratt & Whitney developed a CBEND post-processor which
uses the ASME Code equations to determine the complete stress field
from the MSC/NASTRAN calculated forces and moments. This paper presents the
ASME Code equations used by the CBEND post-processor and compares the
results to equivalent plate models. Based upon these comparisons, the use
of the MSC/NASTRAN CBEND element has been implemented in the design of small
diameter tubes.
- DYNAMIC
MODELING AND ANALYSIS OF SPINNING POLYGON ASSEMBLIES USING MSC/NASTRAN
(Acrobat 438KB) #6693
- Bill Nowak -- Xerox
Corporation
- Courtney James -- Xerox
Corporation
- ABSTRACT: This
paper describes the application of MSC/NASTRAN to calculate the dynamic response
of a spinning polygon, motor, and motor housing used in xerographic printers.
Initially, different levels of model sophistication were evaluated showing
convergence to a representative model. Using the converged model, the dynamic
response of the polygon mirror was evaluated from the effects of base excitation.
Frequency correlation in the 0 to 1000 hertz range was demonstrated to be
better than 10% when compared to a dynamic modal test. Mechanical gain correlation
at the fundamental rotor resonance was of the same order as the modal test
with amplitude variations attributed to the assumed damping of the model and
differences between empirical and analytical response locations. Conclusions
and recommendations on future work are also cited.
- ELECTRO-MECHANICAL
RESPONSE SIMULATION OF ELECTROSTATIC VOLTMETERS USING MSC/NASTRAN (Acrobat
469KB) #6593
- Bill Nowak -- Xerox
Corporation
- ABSTRACT: This
paper describes the application of MSC/NASTRAN to simulate the electro-mechanical
behavior of in situ electrostatic voltmeters. These "tuning fork"
style transducers are used to continuously monitor photoconductor voltage
during xerographic copier and printer operation. Voltmeter theory of operation
is discussed, and finite element model development is detailed showing a
6% correlation of natural frequency with empirical results.
From an existence proof, model boundary conditions
were adjusted to show correct voltmeter dynamic response. Based
on this empirical behavior, structural design modifications were made
to the model until similar dynamic response was analytically achieved. These
modifications were then applied to the hardware and correct performance was
empirically verified.
Conclusions and recommendations on
future work are also cited.
- EXTENDED
DETAILED FINITE ELEMENT ANALYSIS OF A 9.6 METRE AUTOGENOUS SAG MILL (Acrobat
1.52MB) #5393
- John Hadaway -- ANI PRODUCTS
- Eric Hecht -- COMPUMOD Pty. Ltd.
ABSTRACT: Finite
element analysis is becoming an integral part of the design and manufacturing
process of heavy engineering machinery for the mining industry in Australia.
The Grinding Mill division of Australian National Industries (ANI) which is
the division of ANI responsible for design, manufacture and supply of ore
grinding mills to mines throughout Australia and overseas have been using
the MSC/NASTRAN finite element analysis code extensively in all phases in
the supply of their mills.
The finite element analyses of a 9600 mm diameter (5640 mm length) Autogenous
Grinding Mill is used to describe how today's available technology is being
used by one company to design and manufacture machinery for the mining industry.
- FINITE ELEMENT
ANALYSIS OF THE RISER COLUMN CHAINTABLE AND CHAINHAWSE STRUCTURES FOR A FLOATING
PRODUCTION STORAGE AND OFFLOADI NG FACILITY USING MSC/NASTRAN (Acrobat
1.92MB) #4393
- D. J. Twine -- BHP Engineering
Pty. Ltd.
Dr. S. Loganathan -- BHP Engineering Pty Ltd
ABSTRACT: An
overview is given of a recently completed finite element stress analysis of
the Riser Column Chaintable and Chainhawse Structures for an offshore Floating
Production Storage and Offloading (FPSO) oil and gas facility.
The project involved
finite element modeling of a symmetric half model of the chaintable and analysis
of the model under a series of Unit Load Cases and Load Combinations. The
primary objective of the analysis was to quantify stress levels and stress
combinations throughout the structure to enable strength and fatigue capacity
of the chaintable and chainhawse structures to be confirmed.
The model involved approximately
60,000 DOF and analysis was carried out using a CRAY-YMP Supercomputer.
The paper will present
a summary description of the problem and objectives of the analysis, finite
element discretisation of the structure, analysis approach, and quality assurance
checking procedures applied to verify the results.
- FINITE ELEMENT
ANALYSIS (FEA) OF THE STATIC AND DYNAMIC RESPONSE OF THE SHEET MOLD COMPOUNDING
(SMC) STRUCTURE USING THE ENHANCED MODELING TECHNIQUE OF THE ADHESIVE JOINING
REGION (Acrobat 589KB) #6393
- Joon B. Park -- Automated Analysis
Corporation
- Randal H. Visintainer -- Ford
Motor Company
ABSTRACT: An FEA study was
conducted to examine the static and dynamic response of an SMC structure fabricated
by adhesive joining method using MSC/NASTRAN. The appropriate modeling of
the adhesive joining region is essential in precise FEA predictions of static
and dynamic response of the SMC structure presented. An enhanced modeling
technique for the adhesive joining region is presented in this paper. A composite
mechanics approach was used to define the mechanical property of finite elements
along adhesive joining region. Static and dynamic predictions of the enhanced
modeling technique were compared with predictions of the conventional linkage
modeling method in structure analysis.
- A FINITE
ELEMENT METHODOLOGY FOR PREDICTING RELATIVE MOTION OF AVIONICS MODULE CONNECTOR
CONTACTS (Acrobat 99KB) #4193
- Mark H. Morton -- Lockheed Aeronautical
Systems Company
- David S. Layton -- Lockheed Aeronautical
Systems Company
ABSTRACT: This paper presents
a methodology for modeling and predicting electronic module connector displacements
in an advanced avionics system. The system is modeled using finite element theory
and the equations of motion solved using MSC/NASTRAN. Emphasis in this paper
is placed on the finite element modeling (FEM) approach and reduction scheme.
In order to achieve the desired accuracy in analysis, the initial FEM contained
over 20,000 degrees of freedom. A FEM of this size is typically cost prohibitive
to use and sensitive to numerical instabilities, particularly when the frequency
range of interest may be as low as 10 Hertz and exceed 1000 Hertz. Several model
reduction schemes and various superelement approaches are examined in an effort
to reduce model size and improve numerical stability. Results include guidelines
for model reduction of similar type structures, as well as selection of the
appropriate eigenvalue solver and associated parameters when using MSC/NASTRAN.
Of particular interest to the authors was the random response of the connector.
To this end, modal analysis is employed to identify natural modes of vibration.
Forced frequency response analysis using the large mass method provides transfer
functions between the source excitation and the response at the connector. The
transfer functions, along with a user specified input power spectral density
function, are used as input to a random analysis. Results include rms displacements
and frequencies of the connectors.
- MANEUVERING
OF THE SPACE STATION/ORBITER DURING AN ASSEMBLY FLIGHT (Acrobat 1.54MB)
#3093
- Paul A. Cooper -- NASA Langley
Research Center
- Alan E Stockwell -- Lockheed Engineering
& Sciences Company
- Shih-Chin Wu -- Lockheed Engineering
& Sciences Company
- ABSTRACT: A large-angle,
multi-body, dynamic modeling capability was developed to help validate numerical
simulations of the dynamic motion and control forces which occur while berthing
Space Station Freedom to the Shuttle Orbiter during early assembly flights.
The paper describes the dynamics and control of the station, the attached
Shuttle Remote Manipulator System, and the Orbiter during a maneuver from
a gravity-gradient attitude to a torque equilibrium attitude using the station
reaction control jets. The influence of the elastic behavior of the station
and of the remote manipulator system on the attitude control of the station/Orbiter
system during the maneuver is investigated. The flexibility of the station
and the arm had only a minor influence on the attitude control of the system
during the maneuver.
- MODELING
AND ANALYSIS OF 4-STEP 3-D CARTESIAN BRAIDED COMPOSITES (Acrobat 1.04MB)
#7593
- Soheil Mohajerjasbi
-- Boeing Defense & Space Group
ABSTRACT: The
fiber architecture of the preform produced in a 4-Step (l x1) 3-D Cartesian
braiding process is investigated based on a study of the movement of the fiber
carriers on the machine bed. Distinctly different fiber architectures are
identified for the interior, boundary, and corner regions of the preform and
the composite. Since different fiber architectures will result in different
deformation properties, the effective deformation behavior of the composite
is expected to be the result of contributions from these different stiffness
properties.
In contrast with these
findings, some of the present analytical models consider a "unit cell"
as a repeat unit for the braided composite, and attempt to model the mechanical
behavior of the composite from the properties of this unit cell. This unit
cell is in the form of a parallelpiped with yarns connecting between the opposite
corners along the body diagonals.
In this paper, a finite
element based method is proposed for modeling the structure of the 3-D braided
composite, and determining the elastic constants and coefficients of thermal
expansion. MSC/NASTRAN is used in modeling the thermoelastic properties of
the composite. Estimates of elastic constants and coefficients of thermal
expansion are developed as a function of "interior braiding angle".
Among advantages of this
technique are simplicity, and the ability to model and study the response
of complex shapes subject to complex loads applied at the boundary.
- N-250 WINDSHIELD
FINITE ELEMENT MODEL (Acrobat 338KB) #7893
- Masduki Suwandi -- Nusantara
Aircraft Industry Ltd.
- Kurnia Witono -- Nusantara
Aircraft Industry Ltd.
- Nurdin -- Nusantara
Aircraft Industry Ltd.
ABSTRACT: In
analyzing the windshield of N-250, - Indonesian / IPTN's latest aircraft product
- one major issue is how to model the windshield glass panel and the distribution
of the load to its mounting structure.
This paper
concentrates on this issue.
- NON-LINEAR
ANALYSIS OF A PROPELLER BLADE RETENTION SYSTEM (Acrobat 480KB) #3293
- John C. Lambert -- United Technologies
Corporation
ABSTRACT: A primary problem
in the design of aircraft propeller systems is the prediction of blade natural
frequencies. A major problem in predicting these frequencies is determination
of the blade retention stiffness. This stiffness is difficult to determine due
to the many linear and non-linear variables involved in such systems. This paper
discusses the manner in which MSC/NASTRAN V65B was used to advance Hamilton
Standard's methodology in evaluating blade retention stiffness.
- RADIATION
HEAT TRANSFER WITH SPECTRAL SURFACE BEHAVIOR (Acrobat 199KB) #5593
- Mike Chainyk -- The MSC.Software
Corporation
ABSTRACT: Prior
to Version 68, MSC/NASTRAN radiation exchange was restricted to ideal black/grey
opaque surfaces exhibiting diffuse emission, absorption, and reflection characteristics.
Most real surface behavior is considerably more complicated due to varying
degrees of specular, spectral, and temperature dependent properties, as well
as radiant transmission. Generalized numerical treatment of all of these phenomena
simultaneously is beyond the scope of the current Version 68 effort, however,
most materials in a practical engineering sense may be characterized by one
or two dominant surface conditions. In particular, most solar collection device
materials as well as high temperature metals can be satisfactorily described
in terms of their spectral and temperature dependent surface properties. This
problem class is addressed with a method known as the radiation energy-band
approximation.
- A REFINED
METHOD FOR LIVE-LOAD DISTRIBUTION PREDICTION OF BRIDGES AND COMPARATIVE STUDY
(Acrobat 678KB) #5293
- Yohchia Chen, Ph.D.,
P.E. -- The Pennsylvania State University
- ABSTRACT: A
refined analysis method is proposed for predicting the distribution of vehicle
live loads on bridge girders. An effective and efficient iteration scheme
is used to solve the nonlinear equations. Two representative bridge systems
are investigated. The obtained results from the proposed method are compared
to experimental data and those obtained from other analysis methods. The prediction
method for live-load distribution implemented in the current bridge design
code is carefully examined. The paper concludes with a number of actual bridge
examples and recommendations.
- RESPONSE
OF PROTECTIVE STRUCTURES TO INTERNAL EXPLOSIONS WITH BLAST VENTING (Acrobat
1.77MB) #4293
- Y. Kivity -- The MSC.Software
Company
- C. Florie -- The MSC.Software
Company
- H. Lenselink -- The MSC.Software
Company
ABSTRACT: This paper
presents a computational study of the response of generic protective structures
to internal blast waves from high explosive charges. The computations are carried
out with the three-dimensional program MSC/DYTRAN, with explicit treatment of
the fluid-structure interactions inherent to the problem. The modeled generic
structures include frangible panels for blast venting and internal partitions
for blast wave deflection. The structural description includes both a thin shell
approach for thin walled containers and a solid finite element representation
for concrete type structures.
The flow of the detonation products and the ambient air is described employing
an Arbitrary-Lagrange-Euler (ALE) approach. This approach also allows internal
partitions to be attached to the ALE mesh without degrading the computational
efficiency.
- STRUCTURAL
ANALYSIS OF AN 85 FT. FREE STANDING TOWER (Acrobat
946KB) #3393
- Paul F. Martin -- Massachusetts
Institute of Technology
ABSTRACT: An 85'
high rectangular truss type antenna support tower is currently in use. The tower
bracing scheme is typical of and similar to other towers used for this application.
Tower members were designed using conventional analytical techniques as presented
in design codes such as AISC, ANSI/A58.1 and ANSI/EIA-222. Resulting stress
analysis showed factors of safety for all members to be satisfactory and capable
of sustaining design loads. Since a conventional tower bracing scheme was used,
the overall buckling capacity of this tower was assumed to be adequate. Recently
a new antenna configuration proposed for use required additional structural
analysis of this tower. The resulting analysis included an overall buckling
analysis utilizing the MSC/NASTRAN program with the buckling solution sequence.
The buckling analysis revealed that the tower was incapable of withstanding
the design loads for either the original or the proposed antenna configurations.
In conclusion, it should also be noted that the results of this study suggest
that other towers currently in use may also be inadequately designed and subject
to potential failures.
- THERMOMECHANICAL
FINITE ELEMENT ANALYSIS OF STIFFENED, UNSYMMETRIC COMPOSITE PANELS WITH TWO
DIMENSIONAL MODELS (Acrobat
1.53MB) #3193
- Craig S. Collier, P.E.
-- Lockheed Engineering and Sciences Co., NASA Langley Research Center
- Kevin A. Spoth -- Lockheed
Engineering and Sciences Co., NASA Langley Research Center
- Glenn C. Grassi -- The
MSC.Software Corporation
ABSTRACT: A method
is presented for formulating stiffness terms and thermal coefficients of stiffened,
fiber-reinforced composite stiffened panels for input to finite element analysis
(FEA). The method is robust enough to handle panels with general cross sectional
shapes, including those hich are unsymmetric or unbalanced. New thermal coefficients
are introduced to quantify panel response from through-the-thickness temperature
gradients. Equations are defined for stiffness, thermal expansion, and thermal
bending that consider the full complement of membrane, bending, and membrane-bending
coupling. A technique of implementing this capability with a single plane of
shell finite elements using the MSC/NASTRAN² FEA program is revealed. Thermomechanical
analyses of an unsymmetric, hat stiffened, metal matrix composite panel are
shown to demonstrate the accuracy possible with planar, 2-D FEM's. 3-D FEA results
are presented to verify the solutions. Ultimately, the significance of including
this additional accuracy in smeared, equivalent plate 2-D models is proved with
FEA of an aerospace plane.
- VIRTUAL
MASS OF FLUID IN EGG-SHAPED DIGESTERS (Acrobat
316KB) #7793
- Atis A. Liepins -- Simpson
Gumpertz & Heger Inc.
- Hamid Nazemi -- Simpson
Gumpertz & Heger Inc.
ABSTRACT: The
MFLUID capability in MSC/NASTRAN-WS is used to calculate the virtual mass
of fluid in an egg-shaped digester tank. In earthquake response calculations
of this type of tank a finite element analysis of fluid/structure interaction
is needed because simplified methods, such as for cylindrical tanks, are not
available. Described are observations about the performance of the QUAD4 element
for fluid/structure interaction and a verification of the virtual mass matrix.
Useful enhancements are proposed.
Automobile
Applications
- THE
APPLICATION OF FEM-EMA CORRELATION AND VALIDATION TECHNIQUES ON A BODY-IN-WHITE
(Acrobat 1.05MB) #0693
- Marc Brughmans -- LMS
International
-
Kevin Blauwkamp -- GM - Saturn Corporation
ABSTRACT: The paper
reviews the application of FEM - EMA correlation and validation techniques to
a body-in-white, namely the 1991 GM Saturn four door Sedan. The FEM model of
this car consisted of 46830 dof's (half model). A multi-point experimental modal
analysis (EMA) survey was executed for 360 response dof's. Classical techniques
for correlation analysis such as MAC are applied. The paper introduces, as well,
a variation of the MAC calculation that enables a better identification of regions
of difference between FEM and EMA. Error localization methods have been applied
to identify the regions of the FEM model causing most of the discrepancies between
FEM and EMA. An FEM model updating procedure was executed to reduce the difference
between FEM and EMA to acceptable limits.
- BUMPER
DESIGN USING COMPUTER SIMULATION (Acrobat 387KB) #1093
- Hwa-Won Lee -- SsangYong
Motor Company
- Sung-Kuk Jang -- SsangYong
Motor Company
ABSTRACT: In order
to meet the current safety standards, it is necessary that a series of destructive
tests for new vehicles including automotive bumpers to be performed. These tests
are very expensive and time consuming. Therefore, the necessity of economical
design and analysis using finite element method is increasing day by day.
This paper attempts to
present such a design and analysis method, using relatively simple beam model
and fine meshed shell model. The analysis has been performed for center -
center pendulum and barrier hits of a bumper system of XENOY² 1102 newly developed
by GEP (General Electric Plastics US) under the process of injection molding.
Finally, the results
predicted from finite element method are compared with those of experimental
tests to evaluate the analysis procedure.
- DEVELOPMENT
OF A METHODOLOGY TO PREDICT THE ROAD NOISE PERFORMANCE CHARACTERISTICS
(Acrobat 329KB) #0993
- Mark P. Voutyras --
Chrysler Corporation
- William F. Resh -- Chrysler
Corporation
- Kevin R. Thomson --
Chrysler Corporation
ABSTRACT: This
paper describes the development of a methodology for predicting the road noise
performance characteristics of an automotive vehicle system. An MSC/NASTRAN
finite element model of a complete suspension system was constructed and analyzed
for dynamic response. In addition, a customized system simulation software
package, GRADAM, was developed for combining the FEA and experimental results
in order to assess vehicle structural sensitivity to noise and also to study
the effect of suspension design modifications on the interior noise levels.
In the model development stage, the FEM modal and frequency response results
for all the relevant suspension components were validated by comparing with
the corresponding experimental measurements. The interior noise levels were
then obtained through the system simulation software. This customized software
combines the MSC/NASTRAN force output at suspension-to-body attachment points
with the corresponding pressure/force (P/F) experimental data in order to
predict the interior noise levels. The methodology developed herein permits
the noise pressure levels to be determined for desired frequency domains.
Furthermore, this methodology allows design engineers to answer "what
if" questions in order to evaluate the effect of suspension design changes
on the interior noise levels. It is anticipated that the methodology presented
herein will be instrumental in optimizing the noise and vibration (NVH) characteristics
of future car lines.
- FLEXIBLE
VEHICLE SIMULATION OR MODELING VEHICLE SUSPENSION COMPLIANCE AT FORD MOTOR
CO. USING A COUPLING OF ADAMS AND MSC/NASTRAN (Acrobat 712KB) #0793
- Shawn P. McGuan -- Mechanical
Dynamics, Inc.
- Steve Pintar -- Ford
Motor Company
ABSTRACT: The Core
Development Technology group at the Ford Motor Company is actively involved
in correlating analytical (ADAMS) vehicle models with objective (telemetric)
data from instrumented vehicles. In the past, vehicle compliances were introduced
into the ADAMS model by using the ADAMS elements; TIREs, nonlinear BUSHINGs
and BEAMs. With the advent of ADAMS/FEATM,
a data translator which provides a two-way interface between ADAMS and MSC/NASTRAN,
vehicle models may now include the effects of geometrically complex component
stiffness and total body compliance in the ADAMS full vehicle simulation. This
paper examines the effects of these added compliances on an ADAMS vehicle model
by comparing the dynamic toe and camber angles of a vehicle with rigid upper
and lower control arms to a vehicle with flexible upper and lower control arms
built from MSC/NASTRAN data. The results demonstrate that complex problems can
be very efficiently modeled and simulated by combining finite element analysis
(MSC/NASTRAN) and mechanical system simulation (ADAMS) technologies.
- USING MSC/NASTRAN
FOR THE CORRELATION OF EXPERIMENTAL MODAL MODELS FOR AUTOMOTIVE POWERTRAIN
STRUCTURES (Acrobat 879KB) #0893
- L.D. Isley -- Borg Warner Automotive
- W.R. Kelley -- Borg Warner Automotive
ABSTRACT: This paper
describes the methods and analyses used in the correlation of experimentally
determined modal models to analytical solutions. The paper illustrates the significant
benefits of Component Mode Synthesis and Design Sensitivity Analysis options
available in MSC/NASTRAN in the correlation process. Neutral File Interface
programs and remote orthogonality calculation methods that simplify the communication
between the FEA solution and the laboratory results are also discussed. Three
(3) specific experimental procedures formulated the basis for the paper. The
first, a simple free-free beam case is presented. The second and third are examples
of more complex automotive transmission assemblies with special boundary condition
issues and internal component influences. Specific recommendations for improving
correlation potential both in laboratory test methods and in the finite element
modeling task have been provided.
Dynamics
- APPLICATION
OF APPROXIMATE TECHNIQUES IN THE ESTIMATION OF EIGENVALUE QUALITY (Acrobat
582KB) #1193
- B. P. Wang -- The University of
Texas at Arlington
- S. P. Caldwell -- McDonnell Douglas
Corporation
ABSTRACT: An eigenvalue quality
estimate has been implemented in MSC/NASTRAN. The quality estimate is based
on the eigenvalue difference from a lumped and consistent mass matrix formulation.
This difference represents the error associated with the discretization of the
finite element model. Normally two eigensolutions are required to compute the
error estimate. However, several approximate solution techniques have been provided
to efficiently compute the consistent mass matrix eigenvalues. The eigenvalue
quality estimator has been implemented as a set of Direct Matrix Abstraction
Programming (DMAP) alters to SOL 103 (SEMODES) of MSC/NASTRAN Version 67. Several
numerical examples are provided to demonstrate the method.
- APPLICATION
OF MSC/DYNA IN HEAD IMPACT ANALYSIS (Acrobat
205KB) #7093
- Vasudeva Murthy -- Johnson
Controls
- Han Sankara -- Johnson
Controls
- ABSTRACT: The
Federal Motor Vehicle Safety Standard 201 (FMVSS 201) specifies requirements
to afford impact protection for occupants. It provides (see reference 1) that
"when that area of the seat back that is impacted in accordance with
S3.22 by a 15 pound, 6.5 inches diameter head-form at a relative velocity
of 15 mph the deceleration of the head-form shall not exceed 80 g's for more
than 3 ms". This paper presents the results of a head impact simulation
on an automotive seat using MSC/DYNA. The results were correlated with those
from an actual laboratory test. Good correlation was achieved in the deceleration
time history as well as deformation of the structure. Though simulations of
the crash type have been performed on entire vehicles few have been focussed
on the seat to the level of detail here.
- DEVELOPMENT
OF A CALCULATION PROCEDURE INCLUDING FLUID STRUCTURE COUPLING TO ASSESS CAVITATION
EFFECTS (Acrobat 982KB)
#6993
- Gotthard Ph. Rainer
-- AVL - Company for Internal Combustion Engines and Instrumentation Ltd.
- Ernst Gschweitl -- AVL
- Company for Internal Combustion Engines and Instrumentation Ltd.
- Hans Christoph Raffel
-- AVL - Company for Internal Combustion Engines and Instrumentation Ltd.
ABSTRACT: Between cylinder
liner and parent bore of internal combustion engines cooling water flow is
existing.
Due to the operating conditions
cavitation effected by
- dynamic acoustic excitations
and
- fluid flow
may occur.
AVL is investigating both effects
using the MSC/NASTRAN acoustic element to consider the dynamic acoustic effected
cavitation and the AVL developed CFD-software FIRE for the fluid flow effects.
This paper considers only the dynamic
acoustic effect. Here the calculational and experimental work is explained,
which has been done till now to apply MSC/NASTRAN to cavitation calculation.
In addition to this, the difficulties to per form measurements and to compare
the results out of calculation and of measurements are described.
The MAC (Modal Accuracy Criterion)
is used as a tool to compare measurement and calculation. The calculations
are carried out as eigenmode analysis and as forced vibrations.
- AN EQUIVALENT
LINEARIZATION SOLUTION SEQUENCE FOR MSC/NASTRAN (Acrobat 786KB) #3593
- J.H. Robinson -- NASA
Langley Research Center
- C.K. Chiang
-- Old Dominion University
ABSTRACT: A classical
equivalent linearization solution procedure for the geometric nonlinear random
response of structures is incorporated into MSC/NASTRAN by Direct Matrix Abstraction
Programming (DMAP). The equivalent linearization solution sequence was derived
from the existing Super Element Modal Frequency (SEMFREQ) response solution
sequence. The definition of the equivalent linear stiffness matrix in terms
of the MSC/NASTRAN differential stiffness for Gaussian random loads is presented.
The required modification and inclusions to the SEMFREQ solution sequence are
discussed. Results are presented for the nonlinear random response of a simple
and a complex panel.
- EULER BUCKLING
(Acrobat 434KB) #6793
- Kevin E. Arden -- Newport
News Shipbuilding
ABSTRACT: This
paper is intended to investigate the accuracy of MSC/NASTRAN's Solution 105
for use in calculating linear elastic (Euler) buckling modes.
Column buckling, panel
buckling, and stiffened panel buckling is analyzed using Euler equations and
Solution 105. Comparisons and modeling recommendations are made for each type
of structure.
Solution 105 provides
excellent results for Euler type buckling. Panel buckling requires the use
of an adequate number of elements. A convergence plot shows that four QUAD4
elements per half sine wave are necessary for accurate results.
The opinions expressed
herein are those of the author and do not necessarily reflect those of Newport
News Shipbuilding and Dry Dock Company.
- IDENTIFICATION
OF CRITICAL SPEEDS OF ROTORS ATTACHED TO FLEXIBLE SUPPORTS (Acrobat 333KB) #3493
- David Bella -- The MSC.Software
Corporation
- Hans Hartmueller --
BMW Rolls-Royce GmbH
- Dr. Karsten Muehlenfeld
-- BMW Rolls-Royce GmbH
- Dr. Gabriel Tokar --
BMW Rolls-Royce GmbH
ABSTRACT: It is common
practice to include the gyroscopic terms for rigid rotors into the equations
of motion for the calculation of critical speeds. This procedure works well
for the case in which the rotors are connected directly to ground by elastic
and/or damping elements. All calculated eigenfrequencies are critical speeds
of the rotor. If additional degrees of freedom are included to model the actual
support structure, then not all eigenfrequencies are critical speeds. Many of
the calculated eigenfrequencies are simply modes of the support structure. The
procedure presented allows critical speeds to be filtered from the set eigenfrequencies
calculated when the support structure is included in the analysis. The methodology
is used to determine the critical speeds of the BRR 700 series aerojet.
- PSDTOOL
- A DMAP ENHANCEMENT TO HARMONIC/RANDOM RESPONSE ANALYSIS IN MSC/NASTRAN
(Acrobat 1.12MB) #3693
- Alwar Parthasarathy
-- Advanced Technology Systems
Group, Spar Aerospace Limited
- Mohamed Elzeki -- Advanced
Technology Systems Group, Spar Aerospace Limited
- Vivianne Abramovici
-- Advanced Technology Systems
Group, Spar Aerospace Limited
ABSTRACT: This Paper presents
a DMAP framework called PSDTOOL that significantly enhances the scope
of harmonic/random response analysis in MSC/NASTRAN. PSDTOOL addresses
the case where grid-point accelerations (and displacements) form the primary
output of a dynamic analysis and locates response-maxima within and across
subcases and frequencies. In the common aerospace application where the input-excitation
is specified as a base-motion PSD-spectrum in the form of a scalar or
a diagonal matrix, PSDTOOL outputs the RMS (and RSS) responses at all
the grid-points of a finite-element model as a single OLOAD-type table
and locates peak RMS responses over the whole system or over individual
user-defined subsystems. For facilitating high-level system design and
integration, PSDTOOL includes a novel capability for computing mass-weighted
average- responses at 'centers-of-mass' of system and subsystems. The goal
is to automate and condense output-generation and to produce design-data with
speed and confidence. PSDTOOL offers some incidental conveniences such as a
conventional relative-motion formulation of base-excitation analysis
and output-screening in a common co-ordinate system. The DMAP scheme is implemented
as an ALTER in a DBLOCATE-restart from a mode-extraction database and
the various special features are driven by non-standard PARAMeters. Extension
to element-output is being envisioned.
- SOLVING MODAL
EQUATIONS OF MOTION WITH INITIAL CONDITIONS USING MSC/NASTRAN DMAP, PART 1:
IMPLEMENTING EXACT MODE SUPERPOSITION (Acrobat 533KB) #1293
- Ayman A. Abdallah --
Analex Corporation
- Alan R. Barnett -- Analex
Corporation
- Omar M. Ibrahim -- Analex
Corporation
- Richard T. Manella --
National Aeronautics and Space Administration
ABSTRACT: Within the MSC/NASTRAN
DMAP module TRDl , solving physical (coupled) or modal (uncoupled) transient
equations of motion is performed using the Newmark-Beta or mode superposition
algorithms, respectively. For equations of motion with initial conditions, only
the Newmark-Beta integration routine has been available in MSC/NASTRAN solution
sequences for solving physical systems and in custom DMAP sequences or Alters
for solving modal systems. In some cases, one difficulty with using the Newmark-Beta
method is that the process of selecting suitable integration time steps for
obtaining acceptable results is lengthy. In addition, when very small step sizes
are required, a large amount of time can be spent integrating the equations
of motion. For certain aerospace applications, a significant time savings can
be realized when the equations of motion are solved using an exact integration
routine instead of the Newmark-Beta numerical algorithm. In order to solve modal
equations of motion with initial conditions and take advantage of efficiencies
gained when using uncoupled solution algorithms (like that within TRD1), an
exact mode superposition method using MSC/NASTRAN DMAP has been developed and
successfully implemented as an enhancement to an existing coupled loads methodology
at the NASA Lewis Research Center.
- SOLVING MODAL
EQUATIONS OF MOTION WITH INITIAL CONDITIONS USING MSC/NASTRAN DMAP, PART 2:
COUPLED VS. UNCOUPLED INTEGRATION (Acrobat 581KB) #1393
- Alan R. Barnett -- Analex Corporation
- Omar M. Ibrahim -- Analex Corporation
- Ayman A. Abdallah -- Analex Corporation
- Timothy L. Sullivan -- National
Aeronautics and Space Administration
ABSTRACT: By utilizing MSC/NASTRAN
DMAP in an existing NASA Lewis Research Center coupled loads methodology,
solving modal equations of motion with initial conditions is possible using
either coupled (Newmark-Beta) or uncoupled (exact mode superposition) integration
available within module TRD1. Both the coupled and newly developed exact mode
superposition methods have been used to perform transient analyses of various
space systerns. However, experience has shown that in most cases, significant
time savings are realized when the equations of motion are integrated using
the uncoupled solver instead of the coupled solver. Through the results of
a real-world engineering analysis, advantages of using the exact mode superposition
methodology are illustrated.
- SPACE
STATION SOLAR ARRAY POINTING SYSTEM CONTROL/STRUCTURE INTERACTION STUDY USING
CO-ST-IN FOR MODAL REDUCTION (Acrobat
976KB) #6893
- Tarun Ghosh -- Rockwell
International Corporation
- Benigno Muniz Jr. --
Rockwell International Corporation
- Joseph Cheng -- Rockwell
International Corporation
- Marsha Nall -- NASA
Lewis Research Center
ABSTRACT: The
control/structure interaction problem of orienting the Space Station Freedom
(SSF) PhotoVoltaic arrays is solved to achieve desired system pointing performance
using the Beta Gimbal Drive Mechanism. The vibration modes of the on-orbit
SSF Stage Configuration 17 are calculated using MSC/NASTRAN finite element
models which presently comprise a total of 250,000 degrees of freedom. In-house
Direct Matrix Abstraction Programs and post-processors are developed for more
efficient and accurate Craig-Bampton modal reduction with geometric stiffening
and either modal displacement or modal acceleration data recovery. Structural
Dynamic Research Corporation's CO-ST-IN post-processor is used to rank the
vibration modes for control system analysis. The problem of solving an actual
case of ranking modes using CO ST-IN for large-scale SSF application is illustrated.
Examples of calculated control system response including the effects of reduced
flexible mode dynamics are shown.
- SSF
FLEXIBLE MULTI-BODY CONTROL/STRUCTURE INTERACTION SIMULATION (Acrobat
711KB) #1593
- Timothy T. Cao -- NASA
JSC/ES
- Huang-Tsang Chang --
DYNACS Engineering Co.
- Tuyen Hua -- NASA JSC/EG2
ABSTRACT: For a large
structure with the size of
Space Station Freedom, it is important to consider the structural flexibity
in the dynamics and control simulation. Conventionally, structural flexibility
is obtained from the MSC/NASTRAN structural models. The interface between MSC/NASTRAN
structural models and multi-body simulation programs is achieved by a flex-preprocessor.
This approach becomes formidable as the size of finite element models grows
with the evolution of SSF structures. The use of superelement and Craig -Bampton
reduction in MSC/NASTRAN introduces difficulty in interfacing MSC/NASTRAN structural
models with the Station/Orbiter Multi-Flex- Body Berthing Analysis Tool (SOMBAT),
a program developed at JSC to perform flex-multibody dynamics and control simulation.
To handle the dynamic reduction approach in MSC/NASTRAN, the flex-preprocessor
in SOMBAT has been modified, and appropriate DMAP sequences have been developed.
This paper presents the enhanced capability of SOMBAT for the space station
freedom dynamics and control simulation. The procedure is validated through
control structure interaction simulation for space station stage two scenarios.
- A
SUPEREFFICIENT, MSC/NASTRAN-INTERFACED COMPUTER CODE SYSTEM FOR DYNAMIC RESPONSE
ANALYSIS OF NONPROPORTIONALLY DAMPED ELASTIC SYSTEMS (Acrobat
748KB) #1493
- Rong C. Shieh -- MU,
Inc.
ABSTRACT: With
the emphasis on frequency response analysis case, development of the title
computer code capability and application of the latter in evaluation of the
computational efficiency of the MSC/NASTRAN code itself in the dynamic structural
response analysis of nonproportionally . damped elastic systems are made in
this study. In this system, MSC/NASTRAN is used mainly for physical or modal
structural (mass, damping, and stiffness) matrix assembling. The newly developed
CMODEAN (Complex MOde/DEcoupling ANalysis) module uses the structural matrices
as input for complex normal modes (state eigenmodes) calculation and equations
of motion decoupling. Computational efficiency of CMODSTAN over MSC/NASTRAN
for frequency response analysis of nonproportionally damped systems is demonstrated
by an example problem with 225 dynamic degrees of freedom.
Electromagnetics
- EDDY CURRENT
SIMULATIONS FOR THE SSCL LOW ENERGY BOOSTER CAVITY (Acrobat 420KB) #1693
- Y Goren -- Superconducting
Super Collider Laboratory
- L. Walling -- Superconducting
Super Collider Laboratory
ABSTRACT: Eddy
currents are developed in the tuner of the Superconducting Super Collider Low
Energy Booster (LEB) cavity during the LEB frequency sweep. The two main difficulties
created by the eddy currents are excessive tuner-surface heating, and more important,
a reduction in the time response of the tuner. We present a detailed analysis
of the eddy currents for various tuner designs. The analysis has been done using
2D and 3D time-domain finite element codes: PE2D by Vector- Field and MSC/EMAS
by the MSC.Software Corporation. Non-linear analysis was performed utilizing
B-H curves. The codes have been bench marked analytically and by using measured
data for different slotted pillbox structures.
- INDUCTION
FURNACES: INTEGRATED MSC/EMAS, MSC/XL, AND MSC/NASTRAN ANALYSIS (Acrobat
873KB) #2093
- Vern D. Overbye -- STM
Consulting, Inc.
- Glenn H. Stalker --
STM Consulting, Inc.
- Scott M. Schaefer --
STM Consulting, Inc.
- Roy H. VanderHeiden
-- STM Consulting, Inc.
- S. Rajendran -- Mobil
Solar Energy Corporation
ABSTRACT: A generic
induction-heated high temperature furnace is modeled using MSC/EMAS to determine
power loss density distribution in a 3-D segment with a cylindrical coil surrounding
the furnace. MSC/XL is used to display color plots of furnace induced power
loss density as well as magnetic flux density within furnace and coil components.
MSC/XL is next used to generate internal heat generation records for an MSC/NASTRAN
nonlinear steady state thermal analysis using a full radiation matrix (assuming
radiation shields closely spaced). An alternative to full radiation analysis
is presented using a theory developed for radiation - equivalent convection.
The two methods are compared, and furnace temperature contours are presented
using MSC/XL. Results of a C-language program are presented to calculate heat
flux and display the results graphically. Finally, the authors present several
recommendations for forthcoming releases of MSC/NASTRAN to improve user friendliness.
- MAGNETIC
SENSOR DEVELOPMENT USING FINITE ELEMENT ANALYSIS (Acrobat 990KB) #1893
- T.J. Wagener -- Honeywell
Systems and Research Center
- James R. Campbell, Jr.
-- Honeywell Systems and Research Center
- James E. Lenz -- Honeywell
Systems and Research Center
ABSTRACT: Magnetic
finite element analysis has proven to be valuable in the research and development
of magnetic sensors and actuators. The emphasis of this research is not entirely
on design detail, but also on the basic magnetics and material properties on
which devices are based. Examples of this research include: 1) magnetic shielding
for ring-laser gyros, 2) magnetic force modeling for accelerometers based on
the type-two high-temperature superconductors, 3) proximity and position sensors
for aircraft applications, and 4) the dynamics of and losses in electromagnetic
actuators and bearings. These examples represent the wide diversity of magnetic
problems faced by researchers, and demonstrate how solutions to these problems
range from simple two-dimensional models to larger and more complicated three-dimensional
models.
- MSC/EMAS
NONLINEAR TRANSIENT ANALYSES OF MULTITURN COILS WITH ATTACHED CIRCUITS
(Acrobat 622KB) #2293
- John R. Brauer -- The
MSC.Software Corporation
- Charles R. Figer, Jr.
-- The MSC.Software Corporation
ABSTRACT: MSC/EMAS
can be used to model multiturn nonlinear coils with attached circuits. The circuits
are modeled by 0D finite elements, which can be attached to 1D line elements
that represent multiturn windings. The 1D elements can then be MPCd to the 3D
or 2D finite element model containing nonlinear magnetic material. The complete
finite element model is analyzed by nonlinear transient Solution 305. Example
computations of time-varying currents and electromagnetic fields are shown for
an inductor, a transformer, and an induction motor. The induction motor solution
is shown to be aided by the new ADAPT nonlinear transient method that is available
in Version 2.5.
- 3D
NONLINEAR MAGNETIZATION STUDIES OF THIN AMORPHOUS RIBBONS (Acrobat
558KB) #1993
- Richard L. Copeland
-- Sensormatic Electronics Corporation
- Markus B. Kopp -- Sensormatic
Electronics Corporation
ABSTRACT: Three-Dimensional
analysis of a thin amorphous magnetic ribbon is studied using MSC/EMAS. A uniform
static magnetic field is applied at various angles with respect to a nonlinear
isotropic magnetic ribbon by using HSURF loads at certain boundary grid points.
Different finite element meshes were examined in terms of generating a very
uniform magnetic field to a region in the model center representing the thin
amorphous ribbon. A simple uniform mesh produced a more uniform field than a
mesh with much more refinement at the center. The importance of the proper boundary
conditions along with the HSURF loads are discussed. The results clearly demonstrate
the expected closure field around the ribbon and help in understanding the magnetization
distributions in and around thin magnetic regions under an applied uniform field.
- USING FINITE
ELEMENT SOFTWARE TO PREDICT EMC PERFORMANCE FROM ELECTRICALLY SMALL SOURCES
(Acrobat 555KB) #1793
-
Mark L. Markel -- General Motors Corporation
ABSTRACT: A major
limit of the finite element method in the past has been its relative difficulty
to model three-dimensional open configurations found in EMC problems. MSC/EMAS
with its open boundary elements now enables problems to be solved in three-dimensions
that were previously considered solvable only with Method of Moment (MoM) codes
and other techniques. MSC/EMAS is used here to accurately compute radiation
fields from an electrically small source (less than a wavelength) that was previously
solved with method of moments codes, and then to analyze printed circuit radiation
that cannot easily be predicted by MoM.
- USING
MSC/EMAS IN STIMULATING A PARALLEL MICROSTRIP TRANSMISSION LINE (Acrobat
298KB) #2193
- Markus B. Kopp -- Sensormatic
Electronics Corp.
- Vichate Ungvichian,
Ph.D. -- Florida Atlantic University
- Richard L. Copeland,
Ph.D. -- Sensormatic Electronics Corp.
ABSTRACT: During
a crosstalk study of two parallel and coplanar microstrip lines having identical
width and thickness, the MSC/EMAS code was used to calculate the total current
flows on the receptor line, and demonstrate the relationship between substrate
height and crosstalk. The frequency used in the simulations was 200 MHz. One
microstrip trace was driven by a 100 mA ideal current source and terminated
with a 50 ohm resistive load. The other trace was terminated at both ends by
two 50 ohm loads.
MSC/EMAS produced results
that are accurate to within 4 percent of the closed form solution. It also
clearly demonstrated that the magnitude of crosstalk, as a function of substrate
height, asymptotically approaches a final value.
Nonlinear
Applications
- LARGE
DEFORMATION HYPERELASTIC ANALYSIS IN MSC/NASTRAN VERSION 67.5 (Acrobat
586KB) #5693
- Katerina-D. P. Papoulia
-- The MacNeal Schwendler Corporation
- Steve S. Hsieh -- The
MacNeal Schwendler Corporation
ABSTRACT: Version
67.5 of MSC/NASTRAN includes finite deformation analysis for problems that
involve large strain and large rotation. The material law is Green-elastic
(hyperelastic) with a strain energy function of the generalized Rivlin type,
extended to include the effect of compressibility at the nearly incompressible
limit. The stress-strain relations are discussed in some detail as well as
the approach taken to avoid the occurrence of volumetric locking. Examples
are presented that illustrate the capabilities of the formulation to model
problems with large strain and large rotation.
- NONLINEAR
SEISMIC ANALYSIS OF BRIDGES: PRACTICAL APPROACH AND COMPARATIVE STUDY
(Acrobat 721KB) #5793
- Yohchia Chen, Ph.D.,
P.E. -- Pennsylvania State University
ABSTRACT: A simplified
numerical model with an efficient computational scheme is proposed for nonlinear
seismic analysis of bridges. The results obtained from the simplified model
are compared to those from the refined model and other methods. The proposed
model is shown to be especially effective for obtaining maximum responses,
and is practical and economical. Effects of bridge skews on responses are
also carefully examined. The paper concludes with a number of bridge examples
and design recommendations.
- NONLINEAR
SUPERELEMENT ANALYSIS TO MODEL ASSEMBLY PROCESSES (Acrobat 1.09MB) #5993
- Mark J. Stone -- Eastman
Kodak Company
- Vic Genberg -- Eastman
Kodak Company
- ABSTRACT: It
is often desirable to know the residual effect of assembly processes on the
final product. Although only a linear static analysis may be desired, the
changes in loads and constraints throughout the assembly process prevent the
use of a simple linear solution. If the product is fairly complex, it is often
necessary to use a large finite element model. This paper describes the use
of a single nonlinear solution (MSC/NASTRAN V66A SOL 66) using superelements
to analyze a large model subjected to varying loads and constraints. As the
load and support change in each subcase, the structural deflection changes
by adding to or subtracting from the previous deformation state. The model
used represents the High Resolution Mirror Assembly (HRMA) for NASA's Advanced
X-Ray Astrophysics Facility (AXAF). The process represented is the alignment
and assembly of the AXAF mirrors to the support structure.
- SNAP-THROUGH
BUCKLING ANALYSIS OF A SHALLOW GEODESIC DOME USING MSC/NASTRAN (Acrobat
758KB) #5893
- S. Loganathan, BSc Eng
Civil (Hons), M. Eng, PhD -- BHP Engineering
- R.C. Morgan, BE, M.Eng
Sc MIE Aust -- BHP Engineering
ABSTRACT: This
paper illustrates the nonlinear analytical and experimental study of a shallow
geodesic dome comprising thin walled circular hollow sections. A 156-member
shallow geodesic dome that has a rise to span ratio of 1:10 (i.e. a rise of
0.6m to span of 6.0m) was constructed and tested experimentally. The present
investigation is focused to study the snap-through phenomena of the dome subjected
to a static load at the centre of the dome. The dome is discretized as 156
beam elements and its perimeter supports are assumed as ideal pin supports.
Displacement control of the load point was employed to trace snap-through
and this prevents any possible dynamic jump in the vicinity of the snap-through
region. Experimental observation shows that the members near the loading point
deformed severely under the applied load without resulting in any damage to
the welded joints, apart from material yielding in certain members.
MSC/NASTRAN Version 67
installed on the BHP Research CRAY-YMP (EL) SuperComputer was used as the
numerical tool to validate the complex nonlinear behaviour of the dome. The
results of geometrical and material nonlinear analysis of the dome from MSC/NASTRAN
compare well with the experimental results for cases where the displacements
can be reasonably measured with the linear transducers employed. A second
nonlinear large displacement analysis was carried out with MSC/NASTRAN on
a Schwedler dome in which the connection details are based on the Harley Spaceframe
structures. The Schwedler dome considered has a rise-to-span ratio of 1:4
(i.e., a rise of 2.5 m to span of 10.0 m).
Nonlinear
Methods
- IMPROVEMENTS
IN LINEAR BUCKLING AND GEOMETRIC NONLINEAR ANALYSIS FOR MSC/NASTRAN'S SHELL
ELEMENTS (Acrobat 543KB) #4993
- Claus C. Hoff -- The
MSC.Software Corporation
ABSTRACT: This paper
presents an improved approach for linear buckling and geometric nonlinear analysis
in MSC/NASTRAN. The differential stiffness and the internal forces of the QUAD4
and TRIA3 shell elements have been corrected in MSC/NASTRAN Version 68. The
linear stiffness of the shell elements has not been changed. With the corrections
in Version 68, two major capabilities have been improved. The eigenproblem in
linear buckling analysis of thin shells is free of spurious modes which have
been observed in Version 67.5 and earlier Versions. Furthermore, the shell elements
converge better in geometric nonlinear analysis. The theoretical concept of
the corotational formulation in MSC/NASTRAN is summarized briefly. The corrections
of the internal forces and tangent stiffness are explained. Examples are presented
which illustrate the improved behavior of the shell elements in Version 68 as
compared to Version 67.5.
- NONLINEAR
ANALYSIS USING A MODAL BASED REDUCTION TECHNIQUE (Acrobat 530KB) #5193
- D. Shalev -- Israel
Aircraft Industries
- A. Unger -- Israel Aircraft
Industries
ABSTRACT: This paper
presents a solution to nonlinear formulated problems using eigenfunctions computed
by a linear free vibration solution. The system of equations is extremely reduced.
The solution is unique in its formulation as the governing equations represent
the problem continuously and do not require an iterational or incremental solution.
Energy consideration is used and the Ritz method is applied to render the governing
equations. An integrated system was built in which the current analysis functioned
as a MSC/NASTRAN dummy module integrated with MSC/NASTRAN SOL 3 and SOL 24 to
render the mode shapes and geometrical and material properties respectively.
Several numerical examples are presented and compared to solutions from the
literature.
- NONLINEAR
GAP-TYPE SOLUTIONS USING A LINEAR F.E.A. CODE (Acrobat 733KB) #5093
- R. D. Hilton -- Bell
Helicopter Textron
ABSTRACT: The most
common form of structural Finite Element Analysis (FEA) is the linear static
solution, in which the behavior of each element can be characterized as a linear
equation. Linear static FEA cannot be used for problems with nonlinear gap-type
elements, as their load vs. deflection behavior cannot be expressed with a single
linear equation. Examples of gap-type elements include a cable (an axial element
which can transfer tension between its ends, but not compression) and a bearing
contact (two interfering surfaces that can compress against each other, but
do not adhere when separated). For a gap element, the load vs. deflection equation
depends on the sense and magnitude of deflection each loading condition imposes
on the element.
Many common FEA codes
do not support gap elements; for those that do, adding a gap element complicates
the solution by requiring extensive changes to the linear model, and by increasing
the CPU time required (often several times over). As the gap behavior can
vary from one loading condition to the next, a separate solution for each
condition must be obtained.
The Enforced Strain Method
uses an approach in which a compensating enforced strain is used to give linear
elements gap-like load vs. deflection behavior. The technique can be used
with linear FEA codes that do not support gap elements, or can be used as
an alternate solution for gap-capable codes. Benefits of the method are reduced
CPU requirements, the ability to run multiple loading cases, and no need for
superelements.
The Enforced Strain Method
is a more efficient gap solution, particularly when a given model has a relatively
small proportion of gaps, and when multiple loading conditions are required.
An example problem is presented in which the required CPU time was reduced
by 43% as compared to the fastest MSC/NASTRAN gap solution. Though presented
as a program external to MSC/NASTRAN, the method could be implemented through
DMAP alters to the standard linear static solution. Run as a DMAP, CPU time
savings for the example problem would have increased from 43 to 66% as compared
to MSC/NASTRAN's nonlinear gap Solution 66.
- THREE
DIMENSIONAL SLIDELINE CONTACT (Acrobat 938KB) #4893
- Rakesh Allahabadi --
The MSC.Software Corporation
ABSTRACT: Slideline
contacts in MSC/NASTRAN model the separation and sliding of finite amplitude
between three dimensional deforming bodies. The modeling of contact requires
the user to specify slideline planes in which the interaction can occur. The
sliding between bodies occur along lines, specified by lists of grid points,
within the slideline planes. The bodies can have large relative motions within
the slideline planes. However, relative motions outside the slideline planes
are ignored; therefore, they must be small compared to a typical slideline element.
The finite element formulation
for both contact and friction is based on the penalty method. But, the user
need not specify the penalty values as the program automatically calculates
them. The slide line element force vector and the stiffness matrix are derived
from a variational principle using a consistent linearization procedure. The
formulation is capable of modeling nonlinear contact geometry and inelastic
material behavior including large deformation.
The three dimensional
slideline contact is a standard feature in Version 68 for quasi-static analyses
(SOL 106).
- However, a special DMAP
is required for Version 67.5.
- Optimization
- OPTIMIZATION
OF DAMPED STRUCTURES IN THE FREQUENCY DOMAIN (Acrobat 625KB) #2893
- Tsung-hsiun Li -- Iowa
State University
- James E Bernard -- Iowa
State University
ABSTRACT: This
paper presents a way to efficiently compute the sensitivities of steady state
resonant response and discusses the utility of these sensitivities in redesign
and optimization. The resonant response sensitivities are calculated by combining
the new capabilities of MSC/NASTRAN v67 in SOL 108,111 and DMAP solution sequences.
Two examples illustrate the approach.
- OPTIMIZATION
TRIAL ANALYSIS OF A JOURNAL/THRUST BEARING STRUCTURE (Acrobat 779KB) #2993
- Takao Miki -- Mitsubishi
Heavy Industries, Ltd.
- Mitsuru Kondo -- Mitsubishi
Heavy Industries, Ltd.
- Fumio Mizuguchi -- Mitsubishi
Heavy Industries, Ltd.
- Yasuhisa Ogino -- Ryoyu
System Engineering, Ltd.
ABSTRACT: Recently,
due to the need to minimize structural weight and reduce material cost, several
programs are offering optimization capabilities. An optimization capability
has been added to MSC/NASTRAN in V66 and has been enhanced in V67. With V68,
it will be also possible to optimize the shape of a structure.
This paper presents a
trial analysis of optimization capability using the current version (V67)
performed on a journal/thrust bearing structure. While supporting the static
load and satisfying design constraints on stress and displacement, weight
is minimized.
This trial analysis demonstrates
the effectiveness of the optimization capability in MSC/NASTRAN in achieving
satisfactory results while saving much of the designer time which is currently
used in a manual iterative optimization procedure. Improvements such as easiness
of use and shape optimization would help to put this capability to extensive
use in design.
- USING
DESIGN SENSITIVITY FOR STATISTICAL RESPONSE ANALYSIS (Acrobat 690KB) #2793
- Ken Blakely -- The MSC.Software
Corporation
ABSTRACT: Statistical
response analysis computes the statistical distribution of responses, given
the distribution of design variable values. Variation in design variable values
can result from manufacturing tolerances, and it can also be attributed to
a level of uncertainty about the finite element input. Statistical distributions
discussed herein are the standard deviation and variance.
Statistical response
analysis can be accomplished in MSC/NASTRAN by using SOL 200 and DMAP alters
in Version 67.5. This paper describes the theory, alters, and examples.
Pre-
and Postprocessing
- A
COMPARISON OF THREE ADAPTIVE REMESHING TECHNIQUES (Acrobat 742KB) #4693
- Joseph L. Walsh -- FEGS,
Incorporated
ABSTRACT: Adaptive
Mesh Refinement and Adaptive Remeshing of finite element meshes based on results
to ensure result accuracy is a growing field of interest in the analysis modeling
community. This paper will discuss and compare three methods of Adaptive Remeshing
used in conjunction with the FAM Analysis Modeling System.
- EXPOSING
THE MYTHS OF DESIGN TO ANALYSIS DATA EXCHANGE (Acrobat 673KB) #6093
- Joseph L. Walsh -- FEGS,
Incorporated
ABSTRACT: Design/Analysis
integration is a major issue for most companies performing finite element
analysis. This paper will outline some of the underlying issues and difficulties
along with exposing the deficiencies of several attempts at Design/Analysis
integration. This paper will also outline the approach and capabilities of
data exchange based on IGES using MSC/XLfromCAD and FAM along with data exchange
based on STEP.
- "GEOMETRIC"
FE ANALYSIS WITH MSC/XLPLUS (Acrobat 937KB) #4493
- Celso A. Barcelos --
Aries Technology
ABSTRACT: Historically,
finite element modeling has been done independently from the underlying geometry
used for design. Finite element models have largely been created using geometry
which was manually entered, and to a large part, redundant with the geometry
used for design purposes. Lately, advances in solids modeling and FEM software
has enabled engineers to achieve significant productivity gains and unparalleled
ease of use by bridging the gap between these two disciplines.
- JOINING
TETRAHEDRA TO HEXAHEDRA (Acrobat 416KB) #4593
- Alok Mahajan -- Optimal
CAE, Inc
ABSTRACT: In the
context of creating finite element mesh from a solid modeler, for example, ARIES/ConceptStation,
the user can choose between techniques of mapped meshing and free meshing. Mapped
meshing provides greater choice of elements and more control of mesh density.
Mapped meshing usually results in the most computationally efficient mesh. Free
meshing provides for the most rapid production of mesh, sometimes with great
sacrifice in computational efficiency. The best of both worlds would exist,
if the user could choose to use mapped meshing in geometrically simple regions
and free meshing in geometrically complex regions. Because currently available
free meshing algorithms only provide tetrahedra, and because the most efficient
(mapped) mesh consists of hexahedra, a methodology is required for joining these
two non-conforming elements. This study examines a variety of methods for joining
these elements, considers a multiplicity of load conditions, and demonstrates
that joining with small error is possible.
- SHAPE
FUNCTION INTERPOLATION OF 2D AND 3D FINITE ELEMENT RESULTS (Acrobat 679KB) #4793
- Victor Genberg -- Commercial
& Government Systems, Eastman Kodak Company
ABSTRACT: A finite
element program such as MSC/NASTRAN provides displacements, rotations or temperatures
at grid points only. There are a variety of applications which require results
at other locations in the model:
1) Obtaining
displacement boundary conditions on finer resolution breakout models
2) Optical ray tracing on deformed mirror surfaces
3) Placing temperatures from a coarse thermal model on to a finer structural
model.
All of these applications
involve interpolation of results over the finite element model. This paper describes
a general purpose post-processing program to accurately interpolate over a model,
using element shape functions. The user may specify a choice of linear interpolation
for thermal models and solid elasticity models, or cubic interpolation for plate
and shell models.
- TOPOLOGY
BASED ANALYSIS MODELING AND PARAMETER DRIVEN ANALYSIS MODELS IN FEGS FAM 3.0
(Acrobat 455KB) #6193
- Joseph L. Walsh -- FEGS,
Incorporated
ABSTRACT: Finite
element analysis is being used more and more today to evaluate design alternatives
and drive design decisions. The ability to quickly modify an Analysis Model
based on design geometry parameters requires a Topology Based Analysis Model
and may also require Parameter Driven Analysis Models. This paper will discuss
the implementation of Topology Based Analysis Modeling in FEGS FAM3.O Modeling
System allowing for multiple geometric representations and assignment of analysis
attributes to the topological entities. This paper will also discuss the application
of parameter symbols and macros in FAM3.O to achieve Parameter Driven Analysis
Models along with user definable extensions to FAM3.O.
- VARYING
PRESSURE DISTRIBUTION OVER A GROUP OF ELEMENTS USING MSC/XL (Acrobat 436KB) #6293
- Pathuri Rama Murthy
-- WIPRO Infotech Limited
ABSTRACT: A commonly
encountered problem in FEA is applying pressures of linear or non-linear nature,
over a group of elements. This paper presents a simple but effective way of
specifying these kind of pressures using MSC/XL.
Shape
Optimization
- AN
ALTERNATIVE APPROACH FOR IMPROVING THE ACCURACY OF SEMI-ANALYTIC DESIGN SENSITIVITIES
IN SHAPE OPTIMIZATION (Acrobat 510KB) #3993
- GaoWen Ye -- The MSC.Software
Corporation
- Shenghua Zhang -- The
MSC.Software Corporation
-
David N Herting -- The MSC.Software
Corporation
ABSTRACT: The
semi-analytic method has been adopted for shape sensitivity calculations because
it does not require special code for analytic derivatives of element matrices.
However, this method may have serious accuracy problems for which several
approaches have been proposed. These approaches, however, are either lack
of generality or difficult to be integrated with a general-purpose FEM package.
Here, an effective approach to the problem has been developed in which an
iterative algorithm used. It not only improves the accuracy but also provides
error estimators so as to ensure the quality of calculated sensitivities.
In addition, it can be easily integrated with MSC/NASTRAN In this paper, the
basic idea of the approach is first described. Then, a general algorithm based
on the approach is given. Finally, its effectiveness is shown through numerical
results.
- COMPUTER
AIDED SHAPE OPTIMIZATION FOR ENGINEERING DESIGN WITH MSC/NASTRAN (Acrobat
566KB) #3793
- Shenghua Zhang -- The
MSC.Software Corporation
ABSTRACT: The goal
of shape optimization is to find a best shape of a structural component so as
to minimize an objective function subject to various design constraints including
functional and manufacturing constraints. Version 68 in MSC/NASTRAN provides
a tool to solve shape design problems systematically and automatically. This
paper will first define the general shape optimization problem. Then, a new
user interface to generate basis vectors is described. Through several example
problems, the paper shows that the general shape optimization capability in
MSC/NASTRAN can optimize complex shapes of two and three dimensional engineering
components.
- FORMULATION
OF PARAMETER-BASED SHAPE SENSITIVITIES FROM FREE-FIELD SIZE SENSITIVITIES
(Acrobat 911KB) #3893
- Afshin Mikaili -- Iowa
State University
- James Bernard -- Iowa
State University
ABSTRACT: Conventional
finite-element-based structural shape optimization requires the calculation
of grid sensitivities which are much more expensive to compute than size sensitivities.
This paper presents an alternate method of shape optimization which is based
on using size sensitivities (computed using MSC/NASTRAN, Version 66A) to guide
shape redesign. In this method, a thin layer of plate elements is cast on
selected free surfaces of structures modeled with solid selected free edges
are covered with a thin lining of beam elements. While the performance of
the structure remains virtually unaffected by introducing these nearly zero
section elements, the sensitivities of the structural response with respect
to the thickness of these elements provide qualitative insight on the behavior
of the structure as well as a quantitative basis for shape optimization. This
paper also addresses the challenge of calculating parameter-based shape sensitivities
(e.g., sensitivity with respect to a shaft diameter, or a shaft fillet radius)
from the computed free-field size sensitivities. The method is applied to
a pin geometry under two different static loading conditions.
Superelements
- DATA
RECOVERY AND MODEL REDUCTION METHODS FOR LARGE STRUCTURES (Acrobat 761KB) #2393
- Hyoung M. Kim -- McDonnell
Douglas Aerospace - Space Systems
- Theodore J. Bartkowicz
-- McDonnell Douglas Aerospace - Space Systems
- David A. VanHorn --
McDonnell Douglas Aerospace - Space Systems
ABSTRACT: This
paper demonstrates important factors for the application of mode-superposition
methods and component mode synthesis to transient response analyses of large
structures. A theoretical review is presented and numerical results are evaluated
for three case studies. Data recovery techniques based on the mode-superposition
method are evaluated with respect to different types of force input, model
reduction, model size, and computational resources. Cutoff frequency selection
at the component- and system-level of component mode synthesis is discussed
for accurate dynamic response calculations. This paper not only shows the
theoretical differences between different data recovery methods, but also
provides physical insights at each computational stage.
- DMAP
ALTERS TO APPLY MODAL DAMPING AND OBTAIN DYNAMIC LOADING OUTPUT FOR SUPERELEMENTS
(Acrobat 561KB) #2493
- Ted L. Rose -- The MSC.Software
Corporation
ABSTRACT: A pair
of DMAP alters are presented for use in the structured superelement dynamic
solutions in MSC/NASTRAN Version 67.5. The first DMAP alter allows
the entry of a "modal damping" matrix for superelements by using
TABDMP1 entries and the frequencies of the calculated component modes. This
allows the use of damping results obtained from dynamic testing of individual
components in an assembly analysis.
The second alter implements the calculation and output (including plots and
PSD) of the applied dynamic loads on superelements. This provides the user
with a tool to verify that dynamic loads applied to superelements were entered
properly.
- DMAP
ALTERS FOR NONLINEAR CRAIG-BAMPTON COMPONENT MODAL SYNTHESIS (Acrobat
1.43MB) #2593
- Herand Bedrossian --
Rockwell International Corp.
- Ted Rose -- The MSC.Software
Corporation
ABSTRACT: A set
of DMAP (Direct Matrix Abstraction Program) alters for MSC/NASTRAN have been
developed for generating reduced matrices for nonlinear structures using the
Craig-Bampton [1] method. These DMAP alters are currently being used in conjunction
with the standard MSC/NASTRAN component modal synthesis approach to create
a system model for coupled loads analysis of Space Station Freedom (SSF) on-orbit
configurations. Nonlinear Craig-Bampton models of the Photo Voltaic (PV) arrays
are created and combined with the linear Craig-Bampton models of the various
other SSF components using the external superelement approach. In addition,
a modal selection DMAP Alter is provided. This alter is used in combination
with an external FORTRAN program to select a reduced set of component modes
based on the modal strain energy criteria. The procedure is illustrated with
an example problem.
- IMPLEMENTATION
OF THE BLOCK-KRYLOV BOUNDARY FLEXIBILITY METHOD OF COMPONENT SYNTHESIS
(Acrobat 917KB) #2693
- Kelly S. Carney -- National
Aeronautics and Space Administration
- Ayman A. Abdallah --
Analex Corporation
- Arthur A. Hucklebridge
-- Case Western Reserve University
ABSTRACT: A method
of dynamic substructuring is presented which utilizes a set of static Ritz
vectors as a replacement for normal eigenvectors in component mode synthesis.
This set of Ritz vectors is generated in a recurrence relationship, which
has the form of a block-Krylov subspace. The initial seed to the recurrence
algorithm is based on the boundary flexibility vectors of the component. This
algorithm is not load-dependent, is applicable to both fixed and free-interface
boundary components, and results in a general component model appropriate
for any type of dynamic analysis. This methodology has been implemented in
the MSC/NASTRAN normal modes solution sequence using DMAP. The accuracy is
found to be comparable to that of component synthesis based upon normal modes.
The block-Krylov recurrence algorithm is a series of static solutions and
so requires significantly less computation than solving the normal eigenspace
problem.
Testing
and Applications
- CROSS-ORTHOGONALITY
CALCULATIONS FOR PRE-TEST PLANNING AND MODEL VERIFICATION (Acrobat 578KB) #7293
- Ken Blakely -- The MSC.Software
Corporation
- Ted Rose -- The MSC.Software
Corporation
ABSTRACT: Cross-orthogonality
calculations can be used to compare the orthogonality of two different sets
of mode shapes. Two types of calculations are described in this paper: MAC
(Modal Assurance Criterion) and mass orthogonality. These calculations can
be used for pre-test planning to guide proper selection of measurement instrumentation
for a modal test, and can also be used to show the degree of correlation between
modal test and MSC/NASTRAN mode shapes. This paper describes the implementation
in Version 67.5 (via DMAP) and provides illustrative examples.
- FINITE
ELEMENT MODEL CORRELATION FOR STRUCTURES (Acrobat 578KB) #7393
- Ricky L. Tawekal --
PT. PAL - Indonesia (Persero)
- M. Agus Budiyanto --
PT. PAL - Indonesia (Persero)
ABSTRACT: Agreement
between measured response of a structure and numerical predictions using an
initial finite element model (IFEM) is in general poor. An algorithm is developed,
which produces an updated finite element model (UFEM) that is fully correlated
with respect to modal measurements. An incremental nonlinear methodology based
on large admissible perturbations in cognate space is used to produce the
UFEM by postprocessing the results of the initial finite element analysis
(FEA) using MSC/NASTRAN. No additional FEA requiring trial and error adjustment
is required. The UFEM corresponds to a real structure and may differ from
the IFEM in response and correlation variables by 100-300 percent depending
on correlation measures and structural size. Two numerical applications for
a structure are used to assess the strength, and limitations of the large
perturbation methodology.
- PROCEDURE
FOR FRF MODEL TUNING IN MSC/NASTRAN (Acrobat 629KB) #7193
- D.L. Carlson -- Boeing
Computer Services
- S.A. Shapely -- Boeing
Computer Services
- T.F. Yantis -- Boeing
Computer Services
ABSTRACT: Prediction
of aircraft cabin noise relies on accurate frequency response analyses of
engine, strut, nacelle, and wing components. Tuning the finite element model
to accurately reflect the dynamic characteristics of the actual component
hardware is an important part of this process. This paper discusses the development
of a DMAP procedure for implementing Prof. David Ewins' approach to frequency
response function (FRF) tuning in MSC/NASTRAN Version 67. Results are presented
for simple test models which reveal some of the capabilities and limitations
of the procedure.
- TEST/ANALYSIS
CORRELATION FOR MULTIPLE CONFIGURATIONS (Acrobat 773KB) #7493
- T. Ting -- University
of Bridgeport
ABSTRACT: This
paper extends the applicability of an existing sensitivity-based test/analysis
correlation method, which permits the refinement of a finite element model
by correlating with dynamic test results, to permit the simultaneous correlation
with test results of multiple configurations. It also demonstrates a technique
to overcome the limitation of most commercial FE programs in handling the
integrated analysis task for a structure of multiple configurations in mass
distributions, boundary conditions, and structural add-ons. Some promising
features of this application has been revealed through a numerical example.