MSC 1994 World Users' Conference
Proceedings
The conference proceedings for the
1994 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
Civil
Structures
- ANALYSIS
OF HYPERBOLIC SHELL NATURAL DRAUGHT COOLING TOWERS USING MSC/NASTRAN (Acrobat
623KB) #3994
- V. S. N. Raju -- A.P.S.E Board/Hyderabad,
Andhra Pradesh
-
- ABSTRACT:Natural Draught
Cooling Towers are very common in modern day thermal and nuclear power stations.
These towers with very small shell thickness are exceptional structures by
their sheer size and sensitivity to horizontal loads. This paper discusses
the analysis of R.C.C. hyperbolic shell of a Natural Draught Cooling Tower
using Quad8/Quad4 elements of MSC/NASTRAN. Analysis has been carried out for
different cases by varying the mesh size and aspect ratio of Quad8/Quad4 elements
and the results have been compared. Not much variation in results has been
found for these cases except at the base of the shell. At the base of the
shell the Quad8 results are much at variance from quad4 and SAPIV results.
-
- THE INFLUENCE
OF PHASE-DIFFERENCE EFFECTS ON EARTHQUAKE RESPONSE OF CABLE-STAYED BRIDGES
(Acrobat 294KB) #3794
- Hongye Zhou -- China Academy of
Railway Sciences
Youping Chen -- China Academy of Railway Sciences
-
- ABSTRACT: In this paper,
a model of cable-stayed bridge for earthquake response analysis is established.
The earthquake response analysis is performed by using a large-stiffness technique
with MSC/NASTRAN. The influence of phase-difference effects on the earthquake
response is discussed.
-
- REFINED
ANALYSIS FOR SOIL-PIPE SYSTEMS (Acrobat 765KB) #3894
- Yohchia Chen, Ph.D., P.E.-- The
Pennsylvania State University
-
- ABSTRACT: This paper discusses
a finite element-based refined approach for buried pipes under severe earthquake
effects. Modeling and computation techniques using MSC/NASTRAN are described
in detail. A number of realistic pipes are investigated. The ref med analysis
results are compared with those obtained from a simplified method which is
the currently accepted method. Special features and advantages of the program
are demonstrated. Recommendations for analyzing and designing a buried straight
pipe are also made.
DMAP
Applications
- DMAP ALTERS
FOR CALCULATING AND SUMMARIZING RESULTANT FORCES FROM THE APPLICATION OF SPC
AND AUTOSPC CONSTRAINTS (Acrobat 983KB) #994
- Grant Parker -- Northrop Corporation
- John Brown -- Northrop Corporation
Ted Rose -- The MSC.Software Corporation
- Jim Swan -- The MSC.Software Corporation
-
- ABSTRACT: MSC/NASTRAN DMAP
(Direct Matrix Abstraction Programs) alter programs have been written to identify
and summarize all resultant forces from single point constraints (SPC) and
AUTOSPC constraints. This capability was developed primarily as an enhancement
to previous DMAPs for model checking and identifying grounding problems and
constraint checks through the use of strain energy calculations on the stiffness
matrix.
Discussion and examples of the
use of the DMAPs for model verification are presented.
- STIFFNESS-GENERATED
RIGID-BODY MODE SHAPES FOR LANCZOS EIGENSOLUIION WITH SUPORT DOF VIA A MSC/NASTRAN
DMAP ALTER (Acrobat 694KB) #1094
- Ayman A. Abdallah -- Analex Corporation
- Alan R Barnett -- Analex Corporation
- Timothy W. Widrick -- Analex Corporation
- Richard T Manella -- National
Aeronautics and Space Administration
- Robert P. Miller -- National Aeronautics
and Space Administration
-
- ABSTRACT: When using all
MSC/NASTRAN eigensolution methods except Lanczos, the analyst can replace
the coupled system rigid-body modes calculated within DMAP module READ with
mass orthogonalized and normalized rigid-body modes generated from the system
stiffness. This option is invoked by defining MSC/NASTRAN r-set degrees-of-
freedom via the SUPORT Hulk Data card. The newly calculated modes are required
if the rigid-body modes calculated by the eigensolver are not "clean"
due to numerical roundoffs in the solution. When performing transient structural
dynamic load analyses, the numerical roundoffs can result in inaccurate rigid-body
accelerations which affect steady-state responses. Unfortunately, when using
the Lanczos method and defining r-set degrees-of-freedom, the rigid-body modes
calculated within DMAP module REIGL are retained. To overcome this limitation
and to allow MSC/NASTRAN to handle SUPORT degrees-of-freedom identically for
all eigensolvers, a DMAP Alter has been written which replaces Lanczos-calculated
rigid-body modes with stiffness-generated rigid-body modes. The newly generated
rigid-body modes are normalized with respect to the system mass and orthogonalized
using the Gram-Schmidt technique. This algorithm has been implemented as an
enhancement to an existing coupled loads methodology.
-
- TRANSIENT
ANALYSIS MODE PARTICIPATION FOR MODAL SURVEY TARGET MODE SELECTION USING MSC/NASTRAN
DMAP (Acrobat 1.14MB) #894
- Alan R. Bamett -- Analex Corporation
- Omar M. Ibrahim -- Analex Corporation
- Timothy L. Sullivan -- Analex
Corporation
- Thomas W. Goodnight -- National
Aeronautics and Space Administration
-
- ABSTRACT: Many methods
have been developed to aid analysts in identifying component modes which contribute
significantly to component responses. These modes, typically targeted for
dynamic model correlation via a modal survey, are known as target modes. Most
methods used to identify target modes are based on component global dynamic
behavior. It is sometimes unclear if these methods identify all modes contributing
to responses important to the analyst. These responses are usually those in
areas of hardware design concerns. One method used to check the completeness
of target mode sets and identify modes contributing significantly to important
component responses is mode participation. With this method, the participation
of component modes in dynamic responses is quantified. Those modes which have
high participation are likely modal survey target modes. Mode participation
is most beneficial when it is used with responses from analyses simulating
actual flight events. For spacecraft, these responses are generated via a
structural dynamic coupled loads analysis. Using MSC/NASTRAN DMAP, a method
has been developed for calculating mode participation based on transient coupled
loads analysis results. The algorithm has been implemented to be compatible
with an existing coupled loads methodology and has been used successfully
to develop a set of modal survey target modes.
Dynamic
Analysis
- ACCURATE
ENFORCED MOTION ANALYSIS USING MSC/NASTRAN SUPERELEMENTS
- (Acrobat 666KB) #2594
- Christopher C. Flanigan -- SDRC
Engineering Services Division, Inc.
-
- ABSTRACT: The standard
approach for performing an enforced motion analysis in MSC/NASTRAN uses very
large masses and forces to obtain the desired motion at selected locations.
This approach can lead to inaccurate results if the large masses are too large
or too small.
An alternate approach for enforced
motion analysis is presented in this paper. The alternate method uses the
Craig-Bampton superelement capability in MSC/NASTRAN to form the required
matrices for a direct solution of the equations of enforced motion. The need
for large masses is eliminated, resulting in improved accuracy. In addition,
the enforced motion analysis is performed directly, eliminating the need for
Lagrange multipliers.
A rigid format alter for performing
the new enforced motion analysis method is included in the paper. An example
problem is presented to demonstrate the new method and to illustrate some
of the pitfalls of enforced motion analysis.
- ACOUSTIC
SENSITIVITY ANALYSIS USING BOUNDARY ELEMENTS AND STRUCTURAL DYNAMIC RESPONSE
(Acrobat 737KB) #794
Nickolas Vlahopoulos -- Automated Analysis Corporation
- S.T. Raveendra -- Automated Analysis
Corporation
- Chris Mollo -- Automated Analysis
Corporation
-
- ABSTRACT: Structural/acoustic
sensitivity analysis can provide information on how structural design modifications
can affect the noise emitted from vibrating structures. MSC/NASTRAN S0L108
and SOLl1 can be used to compute structural dynamic frequency response sensitivities.
This information can be coupled with Boundary Element (BE) results to derive
the acoustic sensitivity with respect to structural design variables.
In this work two BE formulations,
the Direct and Indirect, have been coupled to MSC/NASTRAN design sensitivity
results to compute the acoustic sensitivity with respect to structural design
variables. The theoretical background of the coupling algorithm is presented
along with some examples of noise prediction in interior and exterior noise
radiation.
- AEROELASTIC
MODELLING OF AN AIRPLANE WITH STAND-BY ACTUATOR USING MSC/NASTRAN FOR FLUTTER
ANALYSIS (Acrobat 481KB) #3394
- Yan Mursal -- Pt.IPTN/Indonesia
Aircraft Industry Ltd.
- Moh. Risdaya Fadil -- Pt.IPTN/Indonesia
Aircraft Industry Ltd.
-
- ABSTRACT: The aircraft
control surfaces that were considered in this paper are driven by a pair of
hydraulically powered servo actuators. One actuator is normally in an active
mode and the other is normally in a stand-by mode. This paper describes an
aeroelastic modeling technique where a control System has two hydraulic failures,
the active mode actuator is failed (e.g. a structural disconnect) and no hydraulic
power comes to the stand-by mode actuator. In this situation the stand-by
mode acts as a hydraulic damper.
In the failure condition, the stand-by
actuator must provide sufficient damping in order the airplane still maintain
flutter free condition. To perform the aeroelastic analysis of the System,
the generalized mass, stiffness and damping of the plant (airplane) equation
must be modified. These tasks were done using the combination of EPOINT, TF
MSC/NASTRAN bulk data entry and DMAP. The EPOINT entry was used to add one
generalized coordinate. In this case it is due to the moment of the actuator
introduced to the airplane. The Nastran TF bulk data was used to introduce
the diagonal terms of the MHH, BHH and KHH matrices. A small DMAP routine
was created to add off-diagonal terms of these matrices and to perform the
analysis automatically. The calculation was done using SOL 145. Some results
are presented as an example and also compared with another method.
- ANALYSIS
AND MODAL SURVEY TEST INTELSAT VIIA DEPLOYED SOLAR ARRAY (Acrobat
469KB) #2794
- K. C. Jiang -- Space Systems/Loral
- R. Gahart -- Space Systems/Loral
-
- ABSTRACT: A nonlinear normal
modes analysis and a modal survey test have been performed to determine the
frequencies and mode shapes of a large flexible deployed solar array for the
Intelsat VIIA series communication satellites under production at Space Systems/Loral.
Test parameters such as gravity, air mass and test fixture stiffness are included
in the analysis. MSC/NASTRAN Solution 105 was used to generate the gravitational
stiffness due to 1-g gravity and Solution 103 was used to calculate the frequencies.
A DMAP Alter was updated for MSC/NASTRAN Version 67 to combine the Solution
105 gravitational stiffness matrix and Solution 103 structural stiffness matrix.
The modal survey test was performed to measure frequencies and mode shapes
for correlation with the analytical results. The deployed solar array was
hung vertically. The solar array was pulled and released suddenly to excite
transient vibrations. The decaying vibration response was measured and analyzed
to deduce the frequencies. The test results show good correlation with the
predictions.
-
- DYNAMIC
DESIGN ANALYSIS METHOD (DDAM) USING MSC/NASTRAN (Acrobat 314KB) #3194
- Pam Barber -- Newport News Shipbuilding
- Kevin Arden -- Newport News Shipbuilding
-
- ABSTRACT: Components on
naval ships are currently analyzed for shock loads due to hostile attacks
using the Dynamic Design Analysis Method (DDAM). DDAM estimates the dynamic
response of a component to a beam excitation resulting from the motion of
the ship's hull.
This paper gives a brief description of the history and use of DDAM, presents
an overview of the mathematics, and demonstrates the use of DDAM in designing
a typical submarine component.
The demonstration problem uses MSC/NASTRAN for the dynamic analysis and modal
summations, and shows how DDAM can be performed using MSC/NASTRAN Solution
103.
The opinions herein are that of the authors' and do not necessarily represent
the opinion of Newport News Shipbuilding.
-
- AN EFFICIENT
PROCEDURE FOR DATA RECOVERY OF A CRAIG-BAMPTON COMPONENT
- (Acrobat 506KB) #2694
- Edward T. Tong -- Rockwell International
- Craig C.J. Chang -- Rockwell International
-
- INTRODUCTION: Dynamic analyses
of large and complex space structures are generally performed using the modal
approach. Component modal syntheses are used frequently so that various companies,
each designing their own hardware, can supply the component models to the
integrator for System dynamic analysis. Of the various techniques of component
modal reduction, the Craig-Bampton procedure is most commonly used. The deliverable
data usually consists of the component Craig-Bampton generalized mass and
stiffness matrices, and the Craig-Bampton transformation matrix. Linear Transformation
Matrices (LTMs) associated with the model generated by the component companies
are used to facilitate data recovery. Sizes of these LTMs range from a few
key bad indicators which are of interest to the integrator to an extensive
data recovery set that drives the component's design. Component modal synthesis
and data recovery therefore form a tandum in dynamic analysis of large space
structures. The two widely used procedures to compute the LTMs are the mode
displacement approach and the mode acceleration approach. Although the mode
acceleration approach is generally perceived to be an improvement over the
mode displacement approach, there are considerations when choosing a data
recovery method.
This paper will formulate a simplified procedure to construct the Craig-Bampton
LTMs using either the mode acceleration approach or the mode displacement
approach. The procedure will be formulated for the general case of statically
indeterminant structures. Further simplification can be made for statically
determinant Craig-Bampton components. A general purpose DMAP routine of MSC/NASTRAN
version 67 encompassing the tandum has been implemented. Sample problems to
demonstrate the procedure with the DMAP are included. Although the DMAP is
written for a Craig Bampton component, it can be extended to a general modally
reduced model.
A disadvantage of the mode acceleration recovery is the costly computation
to construct the LTMs when an applied load at the interior set is present.
One of the recent applications is the plume implingement on the solar arrays
during Shuttle docking with the Space Station. This paper will discuss a cost
saving technique and suggest an approach which reduces cost by utilizing a
'mixture' of the two approaches.
-
- SHAKE
TEST SIMULATION USING MSC/NASTRAN (Acrobat 744KB) #3294
- Randal H. Visintainer -- Ford
Motor Company
- Farhang Aslani -- Automated Analysis
Corporation
-
- ABSTRACT: Advances in Computer-Aided
Testing technology have led to the Simulation of Service Operation and test
track loads in the laboratory. The controlled environment of the lab creates
an ideal Situation for attempts to simulate the lab test. Furthermore, the
concept of up-front engineering using analytical prototype has pushed the
demands on the CAE analysts to develop methodology to simulate operating conditions,
durability events, and laboratory tests. To address this need, the frequency
response solution (SOL 111) of MSC/NASTRAN is used to simulate the vehicle
shake test of a heavy truck. The displacement-controlled lab test was performed
between the frequency range of 20 to 50 Hertz (Hz). The MSC/NASTRAN simulation
of the test and the correlation between the test and analysis results revealed
several important points that should be considered in a computer simulation
using the analytical prototype.
-
- SIMULATION
OF PROVING GROUND EVENTS FOR HEAVY TRUCK CABS USING ADAMS, MSC/NASTRAN, and
P/FATIGUE (Acrobat 862KB) #594
- Farhang Aslani -- Automated Analysis
Corporation
- Manicka Yatheendar -- Automated
Analysis Corporation
- Randal H. Visintainer -- Ford
Motor Company
- David S. Rohweder -- Ford Motor
Company
- Juan Lopez de Alda -- Mechanical
Dynamics Inc.
-
- ABSTRACT: The concept of
up-front engineering using analytical prototype has pushed the demands on
the CAE analysts to develop methodologies which simulate operating conditions,
proving ground events, and laboratory tests well ahead of the availability
of structural prototypes of the vehicle. One purpose of such analysis is to
provide fatigue life prediction at an early stage of the design to permit
the incorporation of design modifications prior to initial tooling release.
The stress history resulting from the operation of the vehicle on the proving
ground events can be simulated by enforcement of the profile of proving ground
events using transient analysis in MSC/NASTRAN However, some of the proving
ground events for heavy truck cabs include tire patch displacement of 12 inches
that can not be simulated in MSC/NASTRAN directly. A methodology has been
developed for use of the ADAMS vehicle model which provides accelerations
at the cab mounts under those events. The acceleration response from the ADAMS
model was used to perform transient analysis in MSC/NASTRAN to predict the
time history of stresses in the cab. The time history of the stresses are
input to the P/FATIGUE program to predict fatigue life of the structure under
specific proving ground events.
-
- A STUDY
ON THE ANALYSIS AND IMPROVEMENT OF THE ACOUSTIC CHARACTERISTICS OF THE MUFFLER
WITH COMPLEX GEOMETRY (Acrobat 466KB) #694
- Jin-Yong Mo -- SAMSUNG ELECTRONICS
Co
- Man-Sun Huh -- SAMSUNG ELECTRONICS
Co
- Jung-Rae Kim -- SAMSUNG ELECTRONICS
Co
- Heui-Jong Kang -- SAMSUNG ELECTRONICS
Co
- Sang-Kyoung Oh -- SAMSUNG ELECTRONICS
Co
-
- ABSTRACT: An acoustic transmission
loss analysis method for mufflers with complex geometry is developed using
MSC/NASTRAN on the basis of acoustic-structural analogy and two-microphone
method. In this study, mufflers with simple and complex shapes are analyzed
using this method and compared with theoretical and experimental results for
verification.
Applying this method to design
of suction muffler of reciprocating compressor, we could obtain 4dB(A) total
noise reduction, especially more than 10dB(A) noise reduction at 500Hz.
Interfaces
to MSC/NASTRAN
- AN ADVANCED
POST PROCESSING METHODOLOGY FOR VIEWING MSC/NASTRAN GENERATED ANALYSES RESULTS
(Acrobat 529KB) #2194
- Michael McMeekin -- Swales and
Associates
- Paul Kirchman -- Swales and Associates
-
- ABSTRACT: This paper presents
an advanced post processing methodology for viewing analysis results generated
from MSC/NASTRAN normal modes analyses, and transient response analyses. In
both cases the analysis results are added as a function of time to the basic
finite element model geometries through specified coordinate transformations,
creating a new deformed geometry at each time step. The final deformed geometries
are rendered for each time step and animated through a public domain software
utility on a personal computer for a final visualization of the analysis results.
The deformed geometries can include adjunct super-elements or Craig-Bampton
substructures. The same methodology has been successfully applied to time
history data from a commercial kinematic software package using the basic
finite element model geometry from MSC/NASTRAN.
-
- CREATING
A FINITE ELEMENT MODEL WITH THE MSC.Aries APPLICATION MODULES (Acrobat
993KB) #2394
- Marianne L. Kronenberg -- The
MSC.Software Corporation
-
- ABSTRACT: Software generated
solid models provide complete and unambiguous visual and mathematical definition
of design objects. The MSC.Aries Solids software application module affords
an easy to use, highly intuitive way of creating solid models to capture the
design intent of engineers and analysts. The objectives of this presentation
are to:
- introduce the techniques applied
to build and modify solid models.
- describe the transition from
the geometric model to the Finite Element model.
- display the results of a linear
static finite element analysis.
- USING
VERSION 67.5 OUTPUT2 NEUTRAL FORMAT OPTION FOR FILE TRANSFER ACROSS DISSIMILAR
MACHINES (Acrobat 297KB) #2494
- John Brown -- Northrop Corporation
- Grant Parker -- Northrop Corporation
- Ted Rose -- The MSC.Software Corporation
- ABSTRACT: A new option
in Version 67.5 provides the ability to write OUTPUT2 files in a machine-independent
format. Northrop's Aircraft Division F/A-18 E/F Program has migrated a large
portion of its engineering computer use from a large mainframe to a multi-node
client/server networked workstation environment. Finite element modeling and
analysis software, both proprietary and commercial, have been migrated to
the workstation - including MSC/NASTRAN.
Special features in Northrop's
mainframe based proprietary pre and post processing code (NCASA) has required
its continued use. This mainframe program requires OUTPUT2 data from MSC/NASTRAN.
Prior to the introduction of workstations, both NCASA and MSC/NASTRAN were
resident on the mainframe, and transfer of files between the programs was
not a problem.
In the workstation environment,
the binary incompatibility with the mainframe precludes the use of MSC/NASTRAN
on the workstation if NCASA post processing capabilities are required. The
new OUTPUT2 option in V67.5, which produces a machine-independent compressed
ASCII format, allows all MSC/NASTRAN processing to be accomplished on the
workstation which results in large cost savings and productivity gains for
Northrop.
The implementation of the OUTPUT2
Neutral Format Option, the RCOUT2 MSC supplied FORTRAN conversion program
on the mainframe, and use of the MSC/NASTRAN Data Definition Language (NDDL)
are presented.
- VARIATION
ANALYSIS BY MONTE CARLO RANDOMIZATION OF LOAD VARIATION SENSITIVITIES
(Acrobat 1.38MB) #2294
- Mark J. Stone -- Eastman Kodak
Company
-
- ABSTRACT: Most analysis
considers only the nominal loads acting on a structure, but there may be significant
impact due to the variation or error in the loads as well. When there are
multiple load sources, the effect from the combination of these load variations
is difficult, if not impossible, to predict. This paper describes the use
of a Monte Carlo randomization method applied to the displacement results
generated from MSC/NASTRAN analyses using sensitivity loads. A Monte Carlo
process is used to efficiently obtain a statistical distribution of possible
results from the random combination of load variations. Using the method presented
minimizes the number of analyses which must be run in order to obtain a population
of results from which accurate conclusions can be drawn. The model used represents
the High Resolution Mirror Assembly (HRMA) for NASA's Advanced X-ray Astrophysics
Facility-Imaging (AXAF-I). The variation analysis discussed considers the
impact from support induced load variations during alignment and assembly
of the AXAF-I mirrors to the mounting structure.
Nonlinear
Analysis
- BUCKLING
AND GEOMETRIC NONLINEAR ANALYSIS OF A TIE ROD IN MSC/NASTRAN VERSION 68
- (Acrobat 630KB) #1594
- George Campbell -- Ford Motor
Company
- Wen Ting -- Ford Motor Company
- Peyman Aghssa -- The MSC.Software
Corporation
- Claus C. Hoff -- The MSC.Software
Corporation
-
- ABSTRACT: The improved
geometric nonlinear capability in MSC/NASTRAN Version 68 is tested on a large
scale finite element model of a tie rod. The static buckling load of a tie
rod is analyzed. The results of the finite element model are compared with
experimental results. The analysis is performed in three steps. First, linear
buckling is analyzed with SOL 105. Second, a nonlinear static analysis with
arc-length method is performed in SOL 106 to determine the instability behavior
of the structure. In the last step, a nonlinear buckling analysis is done
with restart into SOL 106 to determine the nonlinear buckling load. The tie
rod has a strongly nonlinear behavior which is due to material yield and geometric
nonlinear effects. It is shown that MSC/NASTRAN's computed buckling load agrees
well with the experimental buckling load.
-
- A NEW
METHOD DEVELOPMENT TO PREDICT BRAKE SQUEAL OCCURRENCE (Acrobat 453KB)
#1494
- Lajos I. Nagy -- Ford Motor Company
- James Cheng -- Ford Motor Company
- Yu-Kan Hu -- BQUAD Engineering,
Inc.
-
- ABSTRACT: A new method
to predict brake squeal occurrence was developed by MSC under contract to
Ford Motor Company. The results indicate that the stability characteristics
of this disc brake assembly are governed mainly by the frictional properties
between the pads and rotor. The stability is achieved when the friction coefficient
of the pads is decreasing as the contact force increases. Based on the results,
a stable brake system can be obtained without changing the brake structure
by incorporating the appropriate frictional coefficient in the brake system.
The method developed here can be also used as a tool to test the quality of
any brake design in the early design stage.
-
- NONLINEAR
ANALYSIS OF FREE FLIGHT ROCKETS USING MSC/NASTRAN (Acrobat 511KB)
#3694
- David S. Livshits -- TAAS - Israel
Industries Ltd.
- David Saltoun -- MSI Engineering
Software Ltd
-
- ABSTRACT: A finite element
model for nonlinear dynamic analysis of a free flight rocket is developed
in this paper. The rocket response time history is calculated as a result
of aerodynamic loads, dynamic imbalance and thrust misalignment. The aerodynamic
loads are calculated using combinations of NOLINs. The model can perform aeroelastic
stability analysis and loads distribution calculations as a function of time.
A nonlinear aerodynamic behavior can be included in the model for large angles
of attack.
-
- PRODUCTION
ORIENTED NONLINEAR ANALYSIS OF SOLIDS AND STRUCTURES (Acrobat 917KB)
#394
- H. D Hibbitt -- Hibbitt, Karlsson
& Sorensen, Inc.
-
- ABSTRACT: Requirements
for modeling nonlinear effects in routine analysis applications have grown
to the point where "general purpose" finite element-based programs
are expected to offer significant nonlinear modeling capabilities. One result
of this market demand has been this year's announcement of the establishment
of a long term relationship between The MSC.Software Corporation and Hibbitt,
Karlsson Sorensen, Inc. ("HKS"), whereby MSC will package a substantial
set of the capabilities offered by HKS's ABAQUS/Standard program with MSC.Aries,
to supplement the nonlinear capabilities of MSC/NASTRAN and MSC/DYTRAN for
applications in solid and structural analysis. MSC will provide full support
of these capabilities, as it does for its other analysis products.
Nonlinear effects introduce a broad range of issues which might deter the
analyst who is unfamiliar with this type of problem from trusting such modeling
as a basis for achieving design goals and schedules. Once nonlinearity is
introduced into a model, uniqueness and stability of the solution may be (and
often are) lost, and issues of convergence, choice of nonlinear solution algorithm,
etc. must be considered. Nevertheless, the analyst may have no choice but
to face up to these problems: he cannot analyze a design for certain events,
or design the manufacturing process to create a product, without considering
nonlinearity. The viewpoint taken in this paper is that, with mature software
such as the ABAQUS-based products that MSC now offers, some nonlinear effects
of practical importance can be modeled on a routine, production, basis. The
spectrum of difficulty ranges from such cases all the way to problems that
are still research topics. One purpose of this paper is to suggest what level
of difficulty might be anticipated in modeling various nonlinear effects that
are commonly encountered, thus providing some guidance to the analyst in determining
the extent to which expertise is needed in order to utilize nonlinear analysis
software.
-
- SPACE
STATION FREEDOM SOLAR ARRAY WING NONLINEAR TRANSIENT ANALYSIS OF PLUME IMPINGEMENT
LOAD (Acrobat 767KB) #3594
- C. C. Tang -- Lockheed Missile
& Space Company
-
- ABSTRACT: This paper describes
the nonlinear transient analysis of the Space Station Freedom Solar Array
(SSFSA) wing for on-orbit plume impingement bad due to Space Shuttle berthing.
Design features and the finite element model of the SSFSA wing are briefly
described. Nonlinear transient analysis is performed using MSC/NASTRAN SOL
99 (V67) with blanket tensioning accomplished by restarting with static solution
results. The blanket tensioning is from tension mechanisms. Transfer function
(TF), scalar point (SPOINT), nonlinear load (NOLIN1), and damper (CDAMP2)
are used to describe the nonlinear characteristics of the tension mechanisms.
Stiffness updates for capturing the nonlinear geometrical stiffness changes
due to tension variation in the solar array blankets is utilized in the iterative
nonlinear solution. Results, when compared to that from linear transient analysis,
showed that the beam-column effect for the slender mast of the solar array
wing is insignificant, and the assumptions made in the linear transient analysis
are acceptable.
-
- THREE-DIMENSIONAL
SLIDELINE CONTACT IN VERSION 68 (Acrobat 553KB) #1694
- Rakesh Allahabadi -- The MSC.Software
Corporation
- Dianxiang Xiang -- The MSC.Software
Corporation
- Detlef Liebe -- MSGmbH
- Glenn C. Grassi -- The MSC.Software
Corporation
- Peyman Aghssa -- The MSC.Software
Corporation
- Behrooz K. Shahidi -- Ford Motor
Company
-
- ABSTRACT: Slideline contact
was first introduced in Version 67.5 of MSC/NASTRAN through a standalone
DMAP alter - 'contact.v675' available in the /misc/sssalter directory. This
DMAP alter is applicable only for solving static problems. Starting with Version
68, the slideline contact capability is available for solving both nonlinear
static (SOL 106) and nonlinear transient (SOL 129) problems as a standard
feature. The use of the DMAP alter is no longer required.
This paper shares the experience
of using the MSC/NASTRAN slideline contact capability. It (a) demonstrates
the capability through real life applications and (b) provides guidelines
for effective usage.
- VULNERABILITY
ANALYSIS OF AIRCRAFT FUSELAGE SUBJECTED TO INTERNAL DETONATIONS
- (Acrobat 990 KB) #3494
- Geetha Bharatram -- Wright Patterson
AFB
- Capt. Scott A. Schimmels -- Wright
Patterson AFB
- Dr. Vipperla B. Venkayya -- Wright
Patterson AFB
-
- ABSTRACT: The Air Force,
in support of the FAA's (Federal Aviation Administration) Aircraft Hardening
Program (AHP), is conducting an extensive test program involving simple cylinders
to full scale aircraft such as the B-52s as well as representative commercial
airplanes. The purpose of this program is to ascertain the extent of the damage
caused by internal explosions and to develop strategies to protect the safety
of the passengers. The effects of the internal explosion are very complex,
and the tests alone can not provide an adequate understanding to develop protection
strategies. The purpose of this paper is to present the analysis results of
the B-52 aircraft subjected to internal explosions. In addition analysis results
are compared to those obtained from the test program conducted at Davis Monthan
Air Force Base.
-
- Two types of analysis will be
addressed in this paper:
-
- 1. Fluid structure interaction
(blast pressures and airframe interaction) using MSC/DYTRAN.
- 2. Joint and buckling analysis
of a B-52 panel using MSC/DYTRAN.
-
- The ultimate goal of the proposed
analysis is to develop a vulnerability map of the entire fuselage. This map
can be used to make cost effective decisions on hardening of the aircraft
against bomb blasts.
Optimization
- NONLINEAR
ADAPTIVE ANALYSIS VIA QUASI-NEWTON APPROACH WITH MSC/NASTRAN
- (Acrobat 802KB) #1394
- Ortwin .cfmer -- California State
University, Long Beach
-
- ABSTRACT: The Quasi-Newton
method has proven to be the most efficient optimization method. The purpose
of this paper is to apply this numerical procedure for optimization problems
as well as large deflection analysis and animation. A FORTRAN program developed
to calculate constrained optimization problems is used as the basic code within
an iterative nonlinear adaptive analysis. The new numerical procedure calculates
the displacements of an elastic structure due to given loading conditions.
Then the displacements are added to the joint coordinates. In the deformed
position the degrees of freedom of the structure are supported and the negative
displacements are applied as loadings, to move the structure back to the old
undeformed position. The difference of the reaction forces in both positions
specifies the geometric nonlinear adaptive loading conditions. These additional
forces are applied in an iteration procedure, until equilibrium is achieved.
The software ME-BANK (Mechanical Engineering Program-Bank), written in C-language,
was developed to execute MSC/NASTRAN and a constrained optimization FORTRAN-code
via the SYSTEM-function within an iteration procedure.
-
- SHAPE
PARAMETERIZATION AND OPTIMIZATION USING THE BOUNDARY SHAPES CONCEPT
- (Acrobat 1.10MB) #1194
- Hemant D Patel -- The MSC.Software
Corporation
-
- ABSTRACT: The concept of
boundary shapes for parameterization of design boundaries in shape optimization
is introduced. In this concept the boundary definition of the finite element
geometry is designed. In addition the requirement for use of shape basis vectors
with low mesh distortion properties is ideally satisfied by interpolating
domain point sensitivity by applying the boundary shapes or forms as enforced
displacements and updating the shape basis vectors at each design cycle based
on current geometry. This results in smooth mesh changes and minimizes the
need for intermediate remeshing for small to moderate design changes. To support
ease of use and provide flexibility in the prescription of boundary shapes
the concept of auxiliary boundary models as been incorporated in MSC/NASTRAN
as an integral part of the analysis model. The boundary shapes are generated
with auxiliary boundary model analysis by exploiting available options in
static analysis of applied loadings and multiple boundary conditions. Basic
design examples demonstrating the power of the boundary shape approach are
presented.
-
- STRUCTURAL
OPTIMIZATION WITH SOLUTION 2001 IN THE DESIGN PROCESS (Acrobat 2.57MB)
#494
- Ingo Raasch -- BMW AG, Munich,
Germany
-
- ABSTRACT: The paper will
explain the initiation and capabilities of S0L2001, a MSC/NASTRAN DMAP for
structural optimization. The reminder will describe example problems, where
50L2001 has successfully used. Two examples show the achievements in concept
design, followed by an example of a car body in white. Finally some shape
optimization problems of engine components will be shown. A short outlook
to the optimization capabilities of Version 68 will be given. In the conclusions
it will be stressed that optimization is a very valuable (even in the meaning
of $$) tool in the design process.
-
- TOPOLOGY
OPTIMIZATION USING MSC/NASTRAN (Acrobat 990KB) #1294
- B. P. Wang -- The University of
Texas at Arlington
- C M. Lu -- The University of Texas
at Arlington
- R.J. Yang -- Ford Motor Company
-
- ABSTRACT: Recently, Bendsoe
and Kikuchi developed a homogenization method which can be applied to find
the optimal topology of a continuum in a fixed domain. The homogenization
approach is based on an artificial but physical micro-structure whose properties
are homogenized. Alternatively, it has been demonstrated that the solution
of the optimum material distribution problem can be considerably simplified
by employing a density-dependent isotropic material without a specific physical
micro-structure. In this paper, topology optimization for minimum compliance
under static loading and for maximum eigenvalue using this approach has been
implemented using MSC/NASTRAN. Optimal topology for a plate under in-plane
and bending loads is presented. Optimal material distribution for a plate
to maximize the first frequency is also presented.
Stress
Analysis
- THE EFFICIENT
CALCULATION OF STRESS CONCENTRATION FACTORS (Acrobat 891KB) #3094
- D. L. Dewhirst -- Ford Motor Co.
- Wai Ho -- The MSC.Software Corporation
-
- ABSTRACT: Certain stress
concentration problems recur often in the design of torque-carrying shafts.
We desired to construct a set of tables similar to those in Peterson's Stress
Concentration Handbook to permit rapid manual preliminary sizing of these
shafts. Because a large number of parameters were involved, the efficiency
of the modeling process was an issue. This study compares a variety of modeling
techniques with emphasis on the p-adaptive approach available in MSC/NASTRAN,
version 68.
-
- ELASTIC-PLASTIC
ANALYSIS AROUND A CIRCULAR HOLE STRESS CONCENTRATION (Acrobat 752KB)
#2894
- Robert P. Thacker, Jr. -- Boeing
Computer Support Services
-
- ABSTRACT: This paper takes
a look at the ability of the 8 node solid (CHEXA) and the 4 node shell (CQUAD4)
to calculate the plastic surface around a circular hole, when the plate is
loaded bi-axially. The MSC calculated stresses will be compared to two analytical
solutions; one by Galin, the other by Sokolov. The solution by Galin, which
is exact, calculates the boundary of the plastic surface for a plane strain
condition. The solution by Sokolov, which is approximate, calculates the boundary
of the plastic surface for a plane stress condition. First, the CHEXA will
be used in a plane strain condition with two load cases, and 3 different meshes
in each load case. Second, the CHEXA and CQUAD4 will be used in a plane stress
condition with the same two load cases, with 3 meshes for load case 1 and
1 mesh for load case 2. Load case 1 will produce an elliptical plastic surface,
load case 2 will produce a circular plastic surface. The version of MSC/NASTRAN'
is 67.7. The material property is elastic-perfectly plastic. Reading from
the OUTPUT2 file, the nodes and their von Mises stress, along angles 0, 45
and 90 degrees, from the hole to the edge of the plate, will be determined.
The von Mises stress for these nodes will be plotted, such that the nodes
which are plastic and the nodes which are elastic are displayed. These nodal
values will be compared with the analytical solutions of Galin and Sokolov.
All of the models were run on a Cray Y-MP 8I, located at Marshall Space Flight
Center.
-
- EVALUATION
OF MSC'S PARABOLIC TETRAHEDRON FINITE ELEMENT (Acrobat 571KB) #2994
- Kevin E. Arden -- Newport News
Shipbuilding
-
- ABSTRACT: Automatic mesh
generators, based on the solid model geometry, will only produce tetrahedron
elements. Solids based modeling techniques allow for efficient and easy creation
of solid element models. This paper evaluates the accuracy of the element
by comparing closed form solutions and actual test data to solutions calculated
using MSC/NASTRAN.
The test data resulted from a recent design experience where solid modeling
capabilities were beneficial. This design experience is presented along with
the test validation of the finite element results.
The modeler used herein is 1-DEAS VI.l provided by SDRC.
The opinions of this paper are the author's and do not necessarily represent
the opinions of Newport News Shipbuilding.
Test
- Analysis Correlation
- MATCHING
FREQUENCY RESPONSE TEST DATA WITH MSC/NASTRAN (Acrobat 490KB) #1794
- Ken Blakely -- The MSC.Software
Corporation
-
- ABSTRACT: This paper describes
the use of MSC/NASTRAN for matching frequency response test data. MSC/NASTRAN's
design optimization capability (SOL 200) is used to minimize the difference
between the MSC/NASTRAN results and test data. In the procedure, the model
parameters are automatically updated until the analytical results match the
test data. The procedure is enabled in MSC/NASTRAN via the use of a user-written
equation (DEQATN Bulk data entry) that defines the difference between test
and analysis. An example is shown to illustrate the method.
-
- PARAMETER
ESTIMATION USING FREQUENCY RESPONSE TESTS (Acrobat 795 KB) #1894
- D. N. Herting -- FE Tools
-
- ABSTRACT: Structural optimization
techniques in MSC/NASTRAN may be adapted to improve the correlation between
finite element calculations and dynamic test results. The goal of the system
is to reduce the "errors" in the finite element results by predicting
changes to selected structural properties. Modern methods, which minimize
weighted differences between test and analytic results over many excitation
frequencies, have been adapted to the MSC/NASTRAN structural design optimizer.
Response amplitudes from forced sine-sweep excitations are used as the basic
inputs and actual structural properties changes are the calculated results.
This approach bypasses many of the previous difficulties by using the following
methods: 1) The error measures are defined directly from the solution vectors
to avoid large complicated symbolic equation entries and manually transcribed
data tables, 2) Frequency response solutions are used to avoid the difficult
task of calculating eigenvector derivatives, and 3) Constraint equations are
built into the solution to enforce test responses and produce faster convergence.
A minor amount of automated preprocessing is the necessary extra effort to
use the standard V68 system. Test results show the feasibility of the approach,
and perhaps its practicality. Results will be shown for a classical example
problem.
-
- SIMULATION
OF CRASH-TEST USING THE ACCELERATION AS A PARAMETER TO CHECK THEORETICAL AND
EXPERIMENTAL RESULTS (Acrobat 418KB) #2094
- Luiz Carlos H. Ricardo -- Autolatina
Brasil S.A.
- Oscar Bito Augsto -- Universidade
Sao Paulo
-
- ABSTRACT: A compact car
was modeled using MSC/NASTRAN. The car model is composed by 6 beam elements
and 2 rigid elements, also representing the engine and body masses, besides
2 other gap elements for mathematical reasons.
The hyphothesis was that a vehicle
would make a crash-test at 14 m/s, with accelerometers placed in the tunnel.
We have obtained, with this test, the curve acceleration versus time. These
data were used for comparison with the MSC/NASTRAN model. Solution 129, transient
non-linear response from version 67, was used.
Looking at the graphs and comparing
the analysis, the MSC/NASTRAN versus experimental results are very close.
- VALIDATION
OF 3650 DWT SEMI CONTAINER SHIP FINITE ELEMENT MODEL BY FULL SCALE MEASUREMENTS
(Acrobat 757KB) #1994
- Ricky L. Tawekal -- PT. PAL -
INDONESIA (PERSERO)
- N.P. Miharjana -- PT. PAL - INDONESIA
(PERSERO)
ABSTRACT: A vibration
analyses of 3650 DWT Semi Container Ship using MSC/NASTRAN is presented
in this paper. Measurements of the full scale ship are used to verify the
numerical predictions by MSC/NASTRAN. Two finite element models are made
to study the optimum size of the finite element model with adequate accuracy.
The results show a good agreement between measurements and the corresponding
numerical predictions where the differences of the lowest superstructure
global natural frequency of the two models are less than 5%. The finite
element models are then used to predict the effects of structural modification
which was done to improve the vibration behaviour.