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MSC 1997 Aerospace Users'
Conference Proceedings
The conference proceedings
for the 1997 MSC Aerospace 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
Aeroelasticity
- AERODYNAMICS-STRUCTURES
INTERACTION IN AIRFRAME DESIGN, (Acrobat 999KB) #1097, 11pgs.
- V.B. Venkayya and V.A. Tischler--Wright-Patterson
AFB, Ohio
- ABSTRACT: Aerodynamics
and structures interaction play a critical role in airframe design.
It becomes even more significant when viewed in the context of emerging
Multidisciplinary Design Optimization (MDO), because the fidelity
of the aerodynamic and structures models improves the reliability
of the optimal solutions. The primary airframe components affected
by the aero-structures interaction are lifting surfaces such as:
wings, canards, fins, vertical and horizontal tails, etc. The flexibility
effects on the aerodynamic load predictions on modern aircraft can
be very significant. They effect both the steady and unsteady aerodynamic
behavior as well as the stability aspects. There is a growing interest
in both the national laboratories and in industry to develop Aero-Structures
Interaction (ASI) tools.
- COMPUTATION
OF DYNAMIC LOADS ON AIRCRAFT STRUCTURE DUE TO CONTINUOUS GUST USING
MSC/NASTRAN, (Acrobat 819KB) #797, 17 pgs.
- Eduardo A. Rodrigues and
Mauro T. Kamiyama--EMBRAER S.A., Brazil
- ABSTRACT: The
computation of gust loads on the structure of an aircraft is part
of the engineering work during the development and certification
phases of a new project. The present work describes the methodology
used at EMBRAER to compute dynamic loads caused by atmospheric continuous
gusts. The mathematical formulation assumes that the gust phenomenon
is described as a stationary random process and that the aircraft
dynamics is linear. MSC/NASTRAN is used for obtaining the dynamic
system modal data by means of SOL1O3 (normal modes solution), and
the modal amplitudes necessary to generate the dynamic system frequency-response
functions by means of S0L146 (aeroelastic response solution). An
example is given in which the methodology is applied to a modern
jet aircraft.
- COUPLING
FLIGHT CONTROL SYSTEM DYNAMICS WITH AEROELASTIC EQUATIONS OF MSC/NASTRAN,
(Acrobat 207KB) #997, 11 pgs.
- Yan Mursal, Pipit Puspitasari,
and Nineu Disyani--Aircraft Design Div.,PT.IPTN
ABSTRACT: This
paper presents development of a procedure to include flight control
system dynamics with aeroelasticity in MSC/NASTRAN. The specific
application is on flutter analysis of a twin engine propeller aircraft
with the yaw damper flight control system ON. The flutter analysis
is performed using the PK-method.
The yaw damper transfer
functions are introduced into the aeroelastic equations of motion
through a combination of EPOINT and TF entries. One of the extra-points
represents the rudder deflection resulting from the yaw damper system.
The additional generalized unsteady-aerodynamic forces due to this
extra-point are provided with down-washes supplied on DMI entries
in the Bulk Data.
The analysis results
are presented on V-G and V-F diagrams for two configurations, nominal
and yaw damper ON.
- INTERFACING
EXTERNAL, HIGH ORDER AERODYNAMICS INTO MSC/NASTRAN FOR AEROELASTIC ANALYSES,
(Acrobat 748KB) #897, 18 pgs., color
- Brent Whiting--Boeing Defense
and Space Group
- Douglas J. Neill--The MSC.Software
Corporation
ABSTRACT: In the
design of aircraft, it is important to have an accurate simulation
of both the structural characteristics and the aerodynamic characteristics
of the vehicle. For static aerodynamic loads, MSC/NASTRAN uses unsteady
aerodynamics at zero reduced frequency. To utilize the accurate
structural representation of MSC/NASTRAN in the computation of aeroelastic
loads, it is desirable to incorporate aerodynamic and aeroelastic
data into the MSC/NASTRAN solution sequence that better represents
the actual geometry of the vehicle. This entails importing data
that replaces or augments the unsteady data. The Boeing Company,
in conjunction with MSC personnel, has prototyped an interface procedure
that allows the static aeroelastic loads computations in MSC/NASTRAN
to use the rigid aerodynamic forces and aeroelastic corrections
from the A502 High Order Panel Method.
- THE
MSC FLIGHT LOADS AND DYNAMICS SYSTEM, (Acrobat 54KB) #1197, 8 pgs.
- Douglas J. Neill and Greg
Sikes--The MSC.Software Corporation
ABSTRACT: The
MSC.Software Corporation (MSC) developed an aeroelastic analysis
and design capability in the late 1970®s and 1980's as part
of MSC/NASTRAN. This capability includes flutter analysis, gust
analysis and flight loads calculations. The latter is more suited
to preliminary and conceptual design. As aerospace companies move
to simulate the aeroelastic behavior of the vehicle early in the
design cycle, however, there is a need to augment these capabilities
to better fit within the current design processes. This augmentation
includes new system architecture concepts, enhanced data management
and model management and integrated visualization tools that understand
aeroelastic models. Finally, new engineering tools need to be implemented
that can better model aeroelastic phenomena at an appropriate level
of fidelity for use in both vehicle design and production analysis.
This paper will present
the critical requirements of the system as understood from numerous
discussions with aerodynamicists, loads analysts, dynamicists and
aeroelasticians in the aerospace community. Results from this work-in-progress
will be presented where appropriate to illustrate the basic architecture,
data flow and usage paradigms and their interaction with the aircraft
design process.
Aerospace
Engines
CHARACTERIZATION
OF MSC/NASTRAN & MSC/ABAQUS ELEMENTS FOR TURBINE, (Acrobat 379KB)
#2097, 15 pgs.
Lt. Jeff Brown--Air Force Research Lab
ABSTRACT: An accuracy
study of MSC/NASTRAN and MSC/ABAQUS three dimensional element types
was conducted for turbine engine blade natural frequency analysis. Linear,
quadratic, hexahedral, and tetrahedral elements were used with different
mesh densities in the frequency and mode shape predictions. These results
were compared to bench test data and laser holographic mode shapes.
Recommendations are made on the selection of finite element meshes for
future analyses.
DEFLECTION
ANALYSIS OF AERO GAS TURBINE STRUCTURE DURING PROTOTYPE DEVELOPMENT,
(Acrobat 525KB) #2197, 10 pgs.
M.Chandrasekaran and K.Ramachandra--Gas Turbine Research Establishment,
Bangalore, INDIA.
ABSTRACT: This paper
presents a refined finite element procedure to obtain the cold dimensions
of aero engine structural assembly from the dimensions of larger hot gas
flow path and also establish the operating clearances between rotor blades
and casings. The effects of stiffness distribution on the circularity
of casings-frames assembly and its weight optimization are also discussed.
FINITE
ELEMENT ANALYSES OF A LAMINATED BLADE RETENTION SYSTEM, (Acrobat 456KB)
#2297, 18 pgs.
Dennis K. McCarthy and Robert T. Fort--McDonnell Douglas Helicopter Systems
ABSTRACT: Design of
a helicopter main rotor blade retention system is a challenging problem.
This critical system must reliably carry large blade loads while allowing
extreme blade motions. Several different methods for blade retention
systems are currently in service including laminated metallic stacks
(LMS). Due to the lack of precise analytic methods laminated metallic
stack systems have historically been developed through test. A methodology,
developed by the authors, is presented herein to accurately predict
the behavior of a LMS blade retention system. This method uses nonlinear
finite element (FE) analysis to predict LMS motions and stresses. Finite
element results are interrogated to obtain damage and fatigue life predictions.
The analytical results are compared to test data with excellent agreement
thus verifying the methodology.
HYDROELASTIC
ANALYSIS OF A RECTANGULAR TANK, (Acrobat 271KB) #2397, 26 pgs.
M.C. Kim and S.S. Lee--The Aerospace Corporation
ABSTRACT: A hydroelastic
analysis of a rectangular tank is performed using MSC/NASTRAN. Natural
frequencies of slosh modes and hydroelastic modes are evaluated, and
are compared with results from other approaches as well as analytical
values.
Aircraft/Aero/Assemblies
LOCAL
STRESS ANALYSIS OF STIFFENED SHELLS USING MSC/NASTRAN'S SHELL AND BEAM
p-ELEMENTS, (Acrobat 68MB) #4797, 10 pgs.
Sanjay Patel, Claus Hoff, Mark Gwillim--The MSC.Software Corporation
ABSTRACT: In large
finite element models of aircraft structures, traditional h-elements
give sufficient accuracy for most purposes, for example in vibration
analysis. However, for local stress analysis of stiffened shells, h-elements
may give inaccurate answers at shell-stiffener connections. The paper
shows how to use p-elements at those locations where more accurate stresses
are required. P-elements work with the existing h-element mesh. A few
modifications of the input are necessary to convert local parts of the
model into p-elements. The p-version elements improve local stresses
significantly. The increase in accuracy is demonstrated on two examples
of stiffened shells.
MSC DEVELOPMENTS
IN AEROELASTICITY, (Acrobat 41KB) #4497, 9 pgs.
Erwin H. Johnson--The MSC.Software Corporation
ABSTRACT: The MSC.Software
Corporation has a long history of involvement with aeroelasticity. This
paper briefly reviews past development efforts and the current capabilities
in this area. Recent developments that have not been incorporated into
standard documentation are given somewhat more emphasis. This paper concludes
with a discussion of ongoing development activity.
MSC/SUPERMODEL-
A CAE DATA MANAGEMENT AND ADVANCED STRUCTURAL MODELING SYSTEM, (Acrobat
1.2MB) #4597, 11pgs, color
Greg Sikes--The MSC.Software Corporation
ABSTRACT: MSC/SuperModel
supports the processes typically used in the design of large structures
comprised of multiple components, typical of aircraft, jet engines, satellites,
and launch vehicles. The engineering design and analysis of these large
assembly structures is often conducted at the component level with multiple
project engineers or project teams each responsible for a given component.
In addition to modeling and simulating the performance of each individual
component, the assembled vehicle performance must be verified as well.
MSC/SuperModel provides an integrated engineering environment that greatly
facilities the coordination and communication of engineering modeling
and analysis results data among the project team(s). MSC/SuperModel is
a powerful CAE process and data management system with engineering tools
for advanced modeling and simulation.
RANDOM
ANALYSIS USING MSC/NASTRAN ISHELL MODULE, (Acrobat 1.5MB) #4897, 13
pgs.
Mohan Barbela--The MSC.Software Corporation
ABSTRACT: MSC/NASTRAN
version 70 has a new DMAP module called ISHELL that allows users to execute
an external program from within MSC/NASTRAN. This module is very powerful
and can be used to perform various tasks; for example, sorting, margin
of safety calculation, and any data block manipulation using an external
user written program. This paper briefly describes the ISHELL DMAP module
and the procedure to perform random analysis using MSC/NASTRAN ISHELL
DMAP module and an external program.
MSC/DYTRAN
& MSC/FATIGUE
AIRFRAME
WATER IMPACT ANALYSIS USING A COMBINED MSC/DYTRAN - DRI/KRASH APPROACH,
(Acrobat 986KB) #3697, 13 pgs.
Gil Wittlin--Dynamic Response, Inc.
Michael Smith and Ashish Sareen, Ph.D.--Bell Helicopter Textron, Inc.
Marv Richards--Simula Government Products, Inc.
ABSTRACT: This paper
describes a Naval Air Warfare Center (NAWC) sponsored Small Business Innovation
Research (SBIR) Phase I Program to achieve long-range U.S. Navy water
impact design objectives. In this program, a complementary approach utilizing
both a nonlinear finite-element analysis program (MSC/DYTRAN) and a hybrid
impact analysis code (DRI/ KRASH) is used to demonstrate the potential
for airframe water impact analysis. Several water impact conditions were
analyzed comprising various combinations of forward velocity and sink
speed using MSC/DYTRAN and DRI/KRASH. Sampling of results along with test
data are provided with regard to fuselage underside pressure contours,
floor accelerations, airframe-water interactive forces, response comparisons
and trends. No similar results have previously been presented.
AN EVALUATION
OF SERVICE LIFE ANALYSIS OF METALLIC AIRFRAME STRUCTURE WITH MSC/FATIGUE,
(Acrobat 999KB) #3397, color, 15 pgs.
Mark T. Doerfler--Lockheed Martin Tactical Aircraft Systems
ABSTRACT: Initial demonstrations
of MSC/FATIGUE, a comprehensive finite-element based durability analysis
software system, have generated interest because of the potential for
its use to benefit the preliminary design of airframe structure. An evaluation
of the software was performed in order to determine its suitability for
application to this preliminary design environment, and this paper summarizes
the evaluation task. The primary evaluation consisted of comparing fatigue
crack initiation predictions of MSC/FATIGUE with results from another
analytical method, coupon test data, and component test data. Several
positive conclusions resulted from this evaluation of MSC/FATIGUE: 1)
the crack initiation capabilities of MSC/FATIGUE are state-of-the-art
with regard to both advanced CAE/visualization and current fatigue crack
initiation theory, 2) fatigue crack initiation predictions compare favorably
with those generated using another analytical technique as well as with
test data, 3) MSC/FATIGUE is useful for detailed analysis, and 4) MSC/FATIGUE
is a candidate tool for durability assessment during preliminary design.
The primary advantage of MSC/FATIGUE was discovered to be its ability
to locate areas in a structure that may be susceptible to crack initiation.
IMPLEMENTATION
OF A FLUID-STRUCTURE INTERACTION FORMULATION USING MSC/NASTRAN, (Acrobat
287KB) #3597, 15 pgs.
S. S. Lee, M. C. Kim, and D. R. Williamson--The Aerospace Corporation
ABSTRACT: A fluid-structure
interaction formulation has been developed previously for incompressible
fluids with a free surface. The formulation involves a series of transformations
for the coupled fluid-structure equation, which is originally nonsymmetric.
The singularity of the fluid inertance matrix is removed by eliminating
the rigid body slosh mode in the transformations, and the combined fluid-structure
equation is made symmetric. In this paper, a DMAP procedure which implements
the formulation is developed using MSC/NASTRAN.
INTEGRATING
ADAMS AND MSC/NASTRAN IN THE DESIGN CYCLE, (Acrobat 569KB) #3497,
14 pgs.
Dave Riesland--Mechanical Dynamics, Inc.
ABSTRACT: In order
to bring better products to the market faster and at less cost, aerospace
companies around the world are embracing the concept of concurrent engineering
at a system level. ADAMS, the world leader in Mechanical System Simulation
(MSS), ties together diverse component design and analysis technologies
such as Computer Aided Design (CAD) and Finite Element Analysis (FEA)
in a single system virtual prototype, providing a more complete understanding
of product performance. In short, MSS provides the critical enabling
technology for meeting true concurrent engineering goals.
MSC/NASTRAN
Applications
CAD/FEA
INTEGRATION WITH STEP AP209 TECHNOLOGY AND IMPLEMENTATION, (Acrobat
283KB) #1297, 13 pgs.
Keith A. Hunten, P.E.--Lockheed Martin Tactical Aircraft Systems
ABSTRACT: The requirements
to share geometric shape and analysis information in a large-scale system,
especially composite structures, are essential. An emerging standard,
the ISO10300 STEP AP209, has been developed to address the data exchange
to the design/analysis/manufacturing process. This paper describes the
scope, progress and implementation of this effective standards-based
solution.
CREATION
& AUTOMATIC ATTACHMENT OF REDUCED COMPONENT MODELS FOR DYNAMIC ANALYSIS,
(Acrobat 64KB) #1597, 17 pgs.
Ted Rose--The MSC.Software Corporation
ABSTRACT: In most applications,
different groups or even different companies model structures as a series
of individual components. At some point in the analysis process, these
component models need to be assembled to get a "complete" model
of the structure being considered. This paper presents a set of DMAP alters
for MSC/NASTRAN which allow each component to be processed independently
(using the superelement enhancements implemented in V69) and replaced
by a set of reduced matrices representing the properties of the component
as seen by adjacent structure. The alters then allow the creation of assemblies
using any combination of the components, with a special feature, automatic
connection at the boundaries. The alters allow the creation of OTM (Output
Transformation Matrices) for use in data recovery and also allow for assembly
plots showing all elements in all components (even without the bulk data
defining the components).
EFFICIENT
CALCULATION OF TRANSVERSE STRESSES IN COMPOSITE PLATES, (Acrobat 173KB)
#1497, 17 pgs.
Raimund Rolfes--Institute of Structural Mechanics, DLR, Braunschweig,
Germany
Ahmed K. Noor--Center for Advanced Computational Technology, University
of Virginia, NASA Langley Research Center
Klaus Rohwer--Institute of Structural Mechanics, DLR, Braunschweig, Germany
ABSTRACT: Transverse
stresses play an important role in the onset and growth of damage in composite
structures. A post-processing method is presented which provides transverse
shear and normal stresses in composite plates subjected to mechanical
and thermal loads. The analytical formulation is based on the first-order
shear deformation theory and the plate is descretized by using a single-field
displacement finite element model. The procedure is based on neglecting
the derivatives of the in-plane forces and the twisting moments, as well
as the mixed derivatives of the bending moments, with respect to the in-plane
coordinates. The method is easily adapted to commercial FE-codes like
MSC/NASTRAN.
AN EFFICIENT
AND EXACT SOLUTION FOR RANDOM VIBRATION ANALYSIS USING MSC/NASTRAN.PART
I: WHITE NOISE SPECTRUM, (Acrobat 284KB) #3797, 19 pgs.
E. de la Fuente and J. San Millan--Instituto Nacional de Tecnica, Madrid,
Spain
ABSTRACT: A new method
for performing RANDOM vibration analysis within MSC/NASTRAN is presented
in this paper. The method is a direct application of a well known result
of Linear Systems Theory and allows exact computation of RMS values
of any number of structural responses and they can be postprocessed as
if they were originated in a conventional static analysis (in colour plots
for instance). Also the DMAP sequence that allows use within MSC/NASTRAN
solver is included and described. The comparison of the obtained results
with those given by standard method shows the correctness of the DMAP
sequence. Finally, extensions of the capability of the presented method
are outlined.
LANDING
RESPONSE ANALYSIS OF AIRCRAFT WITH STORES USING MSC/NASTRAN, (Acrobat
57KB) #3997, 11 pgs.
Zeng Ning--South West United Machinery Corporation, Chengdu, P.R. China
ABSTRACT: In order
to ensure safety flight of aircraft, it is very important to study the
landing response analysis of aircraft with stores. Earlier aircraft
was considered as a stiff body by reason of its lightweight and large
structural stiffness. However, the structure of modern aircraft changes
into more and more flexible with increasing of size and use of high
strength materials. It would make for more accidents if the elastic
effects were neglected for the aircraft. In this paper, the problem
was solved successfully by means of generalized dynamic reduction and
the large mass method of MSC/NASTRAN. The results in the paper show
that the solution technique using MSC/NASTRAN is effective and feasible,
which is especially suitable for the solution of the dynamic problem
of large-scale structure subjected to base enforce motion.
LINK MESH
MODEL OF AN ELEMENTARY PANEL BAY FOR LINEAR MSC/NASTRAN/PARAMETRIC ANALYSIS
OF STIFFENED SHELLS, (Acrobat 57KB) #4097, 29 pgs.
Steven Basic, MS--Boeing Commercial Airplane Group
ABSTRACT: In light of
the general theory of stiffened shells of least weight, the main chords
and stiffeners are subjected to tensile and compressive stresses while
the web-plates are subjected to shearing stress only.
The link mesh model incorporates ' Quad ' plate and ' Rod ' elements.
The ' Quad ' plate-element nodes, or, alternatively, the ' Beam ' element
nodes of chords and stiffeners are in a 'half-wave-length-out-of-phase'
configuration relative to the ' Quad ' plate-element nodes of the web.
The 'out-of-phase' nodes of chords and stiffeners are connected to the
web edge nodes with an array of visible ' Rod ' element links that are
nearly parallel to chords and stiffeners. The fastener-like ' Rod ' elements
are providing links between nodes of the web and the nodes of chords-
stiffeners to diffuse web shear only. The cross-section area of each elastic
' Rod ' element link is determined by equating its axial stiffness to
the combined shear stiffness of a real fastener, its bearing stiffness
and also the bearing stiffness of the two fastened plates, all in series.
The main advantages of the link-mesh model are:
[1] Inclusion of the elastic displacements of the fasteners themselves
as a very significant component of the panel displacement integral, hence,
improved correlation between modal analysis and measured natural frequencies.
[2] More accurate determination of the 'Load Transfer Factor' i.e. fatigue
life, due to an improved read-out of the shear-flow loads applied to a
fastener (even in the case of heterogene materials, different fastener
diameters, or, non-uniform thickness of fastened plates).
[3] Web subjected to predominant shearing due to an exponential-like diffusion,
while the axial load build-up within chords and stiffeners remains substantially
linear.
[4] Simplicity required
for parametric definition of complex structures.
[5] Elimination of the secondary elastic frame effect of an 'Overlaid
Array of Merged- Node Quad Elements' mesh.
MULTI-SPRING
REPRESENTATION OF FASTENERS FOR MSC/NASTRAN MODELING, (Acrobat 322KB) #1397,
13 pgs.
Alexander Rutman, Ph. D,and Joseph Bales-Kogan, M. Sc.--Boeing Commercial
Airplane Group
ABSTRACT: The paper
describes a particular modeling approach for 3-dimensional representation
of fastener joints developed for MSC/NASTRAN. Different physical properties
of plate-fastener systems are analyzed separately and interaction between
them is established. Calculations of the system properties are shown,
as well as the technique of their application in models. Description
of a program automating generation of additional cards required by the
method is included. The procedure is illustrated with an example showing
both an application of the method and results of FEA based on its implementation.
OPTIMIZATION
OF THE C/SiC THRUST CHAMBER FOR A 400N THRUSTER, (Acrobat 364KB) #3897,
10 pgs.
Georg Fleischmann and Ernst Dieter Sach--Daimler-Benz Aerospace AG
ABSTRACT: In order to
minimize the stresses in the laminate, an optimization analysis was performed
wfth MSC/NASTRAN. Design variables were ply thicknesses and fiber orientations.
The results showed that the stresses perpendicular to the fibers cannot
be influenced because they are primarily caused by the temperatures loads.
The shear stresses, however, could be reduced by a factor of 2 compared
with a quasi-isotropic lay-up.
MSC/NASTRAN
& MSC/PATRAN Applications
AUTOMATIC
3D MESH GENERATION CONFORMING A PRESCRIBED SIZE MAP, (Acrobat 1.35MB)
#4197, 23 pgs.
Paul Louis George--INRIA, Gamma Project, France
Houman Borouchaki--UTT, GSM-LASMIS, France
ABSTRACT: The generation
of an adequate mesh is an essential pre-requisite in any finite element
simulation of a physical phenomenon described in terms of PDE's. This
paper introduces a method enabling to generate a three-dimensional mesh
conforming a user-specified size map. This Delaunay-type method creates
isotropic tetrahedral meshes conforming the specified size map. This method
proved to be especially suitable in mesh adaption schemes (mesh, numerical
computation, error estimate)
INTERFACE
ELEMENTS IN GLOBAL/LOCAL ANALYSIS - PART 2: SURFACE INTERFACE ELEMENTS,
(Acrobat 1.3MB) #4397, 18 pgs.
John E. Schiermeier--The MacNeal-Schwendler Corporation
Jerrold M. Housner and Jonathan B. Ransom--NASA Langley Research Center
Mohammad A. Aminpour--Applied Research Associates, Inc.
Jefferson Stroud-- NASA Langley Research Center
ABSTRACT: When performing
global/local analysis, the issue of connecting dissimilar meshes often
arises, especially when refinement is performed. One method of connecting
these dissimilar meshes is to use interface elements. In the previous
Part 1, curve interface elements, implemented in MSC/NASTRAN Version
69 for shell and beam p-element edges, were presented. In the current
Part 2, surface interface elements, being implemented in MSC/NASTRAN
for solid and shell p-element faces, are presented with examples.
SENSITIVITY
EVALUATION ON SPHERE ATTACHMENT SHEAR STRENGTH, (Acrobat 150KB) #4297,
8 pgs, color
T. E. Wong and H. K. Jew--Hughes Aircraft Company
ABSTRACT: A submodeling
technique using MSC/PATRAN program and ABAQUS nonlinear finite element
code, combined with a Taguchi design-of-experiments approach, was used
to optimize the shear strength of spherical ball attachment on an aluminum
nitride substrate. In the current design, the sphere is brazed onto a
gold solder pad on the backside of the substrate using a gold-tin solder.
In the present study, the
finite element model was first calibrated by test. Three design parameters
were then chosen to evaluate the impact of variation of these parameters
on the attachment shear strength. Analysis results indicate that the
solder pad size is the most critical parameter affecting this shear
strength, and the misalignment between the sphere and the solder pad
is the next most critical. Therefore, to effectively improve the attachment
shear strength, it is recommended to: (1) Use a larger solder pad; and
(2) Minimize the misalignment between the sphere and the mounting solder
pad. By implementing only the first recommendation into the current
design, i.e., increasing the pad diameter from 0.02 in. to 0.03 in.,
the attachment shear strength could be improved by 160%.
MSC/PATRAN
& Other MSC Products
BATCH
COMPUTING IN CLIENT/SERVER IT-INFRASTRUCTURES USING LSF AND THE MSC/ANALYSIS
MANAGER, (Acrobat 19KB) #3297, 4 pgs.
Klaus-Peter Wessel--Daimler Benz Aerospace Airbus
ABSTRACT: In typical
CAE downsizing projects the functionality of Batch-Queueing systems existing
on the old mainframe based architecture must be replaced with equivalent
or better systems on the new client server based architectures.
Daimler Benz Aerospace Airbus
has realized this with the integration of the MSC/Analysis Manager (P3/AM)
and LSF (Load Sharing Facility). LSF
integrates all participating workstations to a "virtuell cluster".
LSF measures a number of load indices, basis for the decision on which
workstation a batch-job will be executed. P3/AM prepares the job data
to be copied to the execution workstation and at the end of the job to
be copied back to the submit workstation. During the runtime of a big
CAE job no network traffic occurs. The CAE-user sees only "one"
system and did not have to setup any OS-command to run a batch job on
other machines than his own. The overall turn around time of CAE jobs
can be dramatically reduced because the integration and accessibility
of non or only light-loaded workstations. P3/AM
is the end-user tool for CAE batch submit and monitoring. Beside MSC/NASTRAN
other standard CAE-applications (e. g. Marc, Emas, LS-Dyna) can be used
with P3/AM, as well as self-developed Fortran based job chains. Not only
on the user´s own workstation but also on pure batch-servers without
any interactive access. P3/AM is an easy to use and customizable graphical
user I/F, therefore the development of GUI´s (which is often done
by companies running downsizing projects) can be minimized.
DESIGN
OF AN INTELLIGENT STRUCTURAL QUALIFICATION ENVIRONMENT USING MSC/PATRAN,
(Acrobat 175KB) #3197, 12 pgs.
N.J. Dullaway and A.J. Morris--Cranfield University, England.
ABSTRACT: Increasingly,
modern structures are becoming ever more complex, large and expensive
particularly when large full scale or similar qualification tests are
required. This is particularly true when the structure being designed
is safety-critical. In addition, questions are now being asked about the
ability of conventional test practices to adequately qualify and validate
new structures. This is a situation which is causing concern in a number
of industrial domains including aerospace, maritime and civil engineering.
The arrival of computer-based analysis, particularly finite element analysis,
has provided the ability to reduce reliance on conventional, or "real",
testing and instead go down the path of "virtual" testing. However,
virtual testing raises the question of the reliability of analysis and
the possibility that the use of poor procedures in the analysis process
may produce results that at best are meaningless and at worst are extremely
dangerous. This paper describes SAFESAä (SAFE Structural Analysis),
a research project to develop a computer-aided engineering environment
for automated structural qualification in a range of domains by means
of virtual testing. This application is built on the MSC/PATRAN &
MSC/NASTRAN platform and implemented using PCL as the development language.
OPTIMIZING
THE ENGINEERING PROCESS AT ROCKETDYNE USING MSC/MVISION, (Acrobat
217KB) #3097, 14 pgs, color
Terry Wong--Boeing North American, Inc.
ABSTRACT: In a market
where engineers are increasingly being called upon to consider cost
and process cycle times in addition to the technical merits of a design,
many companies are beginning to realize the important role that materials
play in the design of a part. In order to produce a product in a timely
and cost efficient manner, a materials engineer who develops design
properties must be able to turn test data into design data quickly and
accurately. This data must then be made available to the users in a
timely fashion. Merely having an abundance of materials properties data
is not sufficient to meet the growing demands of a competitive marketplace.
The data must be easily retrieved and easily sorted by the user. There
must also be a process which can convert the data to a form that is
easily usable by software products and processes, such as Computer Aided
Design (CAD) and structural analysis programs.
Faced with the above demands,
the Rocketdyne Division of Boeing North American decided to implement
a materials properties database to meet the above needs. After taking
input from engineers in various processes, reviewing several commercially
available software packages and even looking into building our own database,
we decided to use MSC/MVISION [1] as our official database. We are in
the early stages of the database implementation and have already reaped
many benefits from its use, and foresee more benefits once the database
becomes part of the routine design-to-production process. The implementation
of the materials database has not come without difficulties. This paper
will discuss both the benefits that Rocketdyne has experienced and the
difficulties that we face in the implementation of a material design
properties database.
THE USE OF AUTOMATIC TET MESHING
WITHIN A CONCURRENT ENGINEERING ENVIRONMENT, #2997cr
(Acrobat 7MB, color) or #2997bw (Acrobat 1.44MB,
b&w;), both 15 pgs.
C.P. Griffiths--British Aerospace
ABSTRACT: The use of
CATXPRESS to enable CATIA solid geometry to be transferred to MSC/PATRAN
has been investigated. This geometric data has then been used to generate
a finite element model using the automatic meshing routines available
in MSC/PATRAN. New working methods have been developed which make use
of this facility and three examples of 'real' engineering problems are
presented.
Optimization
and Nonlinear
ADJOINT
SENSITIVITY ANALYSIS IN MSC/NASTRAN, (Acrobat 322KB) #2897, 12 pgs.
Erwin H. Johnson--The MSC.Software Corporation
ABSTRACT: The Adjoint
Method for sensitivity analysis can sometimes produce sensitivities at
a fraction of the computer resources required by the Direct Method. This
paper presents the motivation, theory, implementation and selected results
from installing this technique in Version 70 of MSC/NASTRAN. The application
of the method to large scale design tasks is seen to ¾¾enableš
the practical solution to design tasks driven by NVH (noise, vibration
and harshness) considerations. Concluding comments summarize the results
and discuss possible further developments.
BOSS-QUATRO
AND MSC/PATRAN: A NEW GENERATION OF OPEN-ARCHITECTURE MULTIDISCIPLINARY
OPTIMIZATION SOFTWARE, (Acrobat 215KB) #2497, 16 pgs.
Patrick Morelle--SAMTECH s.a.
John Klintworth--MSC Ltd.
ABSTRACT: Today's
design in industry is in fact a combination of techniques whose primary
goal is to understand the model's behavior. The next step is then to
analyze the performance of the model using numerical simulation. Various
sequences of trade-off, parametric analysis, sensitivity analysis, are
then performed in order to formulate the final optimization problem
properly. A basic feature of many design problems is their multi-disciplinary
nature. As a result, more and more physical phenomena are being modeled
and taken into account in the design problem formulation. This has required
the use of more disparate and heterogeneous analysis and simulation
software.
For those reasons, Samtech
s.a. has developed an open design and optimization architecture: BOSS-QUATTRO.
This new software has been applied with success in multi-disciplinary
(e.g. fluid/structure) analysis and optimization as well as in parametric
studies and Monte Carlo analysis. In particular, a very powerful system
has been built by linking the BOSS-QUATTRO system to the MSC/PATRAN
environment, providing new capabilities for multi-disciplinary optimization
by taking advantage of MSC/PATRAN's existing links to multiple analysis
codes.
The BOSS-QUATTRO environment
is designed as an application manager: it includes existing analysis
chains in arbitrary loops and sequences, and provides new capabilities
like parametric studies, Monte-Carlo simulation, sensitivity analysis
or optimisation. BOSS-QUATTRO is linked to application programs in a
standard way through drivers. This open architecture means that the
system is able to exchange information with present and future commercial
products as well as with in-house codes. For example, drivers exist
for popular commercial software MSC/PATRAN, MSC/NASTRAN, SAMCEF, PRO-ENGINEER
and CATIA. In addition, any application using a text file for input
and output can be linked through a flexible "neutral" driver.
Within the present paper,
two applications developed in the context of a BRITE/EURAM project (MODSYSS,
CT94-0590) are presented. The first takes advantage of links between
MSC/PATRAN and several analysis codes to perform multidisciplinary analyses
on a component. The second links a parametric CAD system to an analysis
code to allow full three-dimensional shape optimization. These examples
demonstrate the ability to link together disparate commercial software
systems to perform effective design optimization.
DETERMINISTIC
DESIGN, RELIABILITY-BASED DESIGN AND ROBUST DESIGN, (Acrobat 78KB)
#2597, 11 pgs.
Wei Wang and Justin (Y.T.) Wu--Southwest Research Institute
Robert V. Lust--General Motors Research & Development Center
ABSTRACT: Due to the
inherent uncertainties or variabilities in loads, materials and manufacturing
quality, variabilities are unavoidable in structural responses. To ensure
the reliability of a structure, these uncertainties or variabilities must
be considered during structural design. Through a simple cantilever box
beam example, the concepts and practices of three design methodologies:
deterministic design, reliability-based design, and robust design, are
examined in this paper. Particular attention is given to the meaning of
robust design and its definition in the context of reliability-based design.
Several robustness criteria are studied and proposed in an attempt to
search for a proper objective function in a reliability-based design framework.
The stress analysis is carried out using both MSC/NASTRAN and an analytical
formula.
NEXT GENERATION
STRUCTURAL OPTIMIZATION TODAY, (Acrobat 1.1MB) #2697, 14 pgs,
color
Craig S. Collier, P.E., Mark Pickenheim, and Phil W. Yarrington--Collier
Research & Development Corporation
ABSTRACT: Characteristics
of a next generation software product are presented for a coupled MSC/NASTRAN
FEA and structural optimization system. These characteristics include
methods for automated structural analysis and optimization such as a
statistical approach for determining 'design-to' loads and analytical/numerical
'zooming' for detailed global to local response. Software characteristics
include a collection of standard panel and beam concepts, and an object
oriented approach to strength and stability failure analyses. These
features are provided in a multiproject, multiuser, secure database
environment where the Internet standard Virtual Reality Modeling Language
(VRML) is used for visual interpretation of results.
NONLINEAR
STRENGTH AND STABILITY ANALYSIS OF A LANDING GEAR COMPONENT, (Acrobat
1.17MB) #2797, 15 pgs.
Andrew Mera--The Boeing Company
ABSTRACT: The reserve
strength of an aircraft landing gear beam is evaluated, using an MSC/NASTRAN
finite element model. The load is incremented until positive margins of
safety can be demonstrated for the various design criteria considered.
Differences in simulated behavior are identified when the model formulation
includes initial stress stiffening, geometric and material nonlinearity,
and instability. The sensitivity of the results is investigated to variations
in end restraints and to geometric imperfections.
Process
Strategies
HP AND
MSC COLLABORATION ON MSC/SUPERMODEL, (Acrobat 114KB) #697, 6 pgs.
Harvey Ivory--The MSC.Software Corporation
Andrew Page--Hewlett-Packard
ABSTRACT: Recently graphics
visualization problems have become too complex for current graphics hardware
and software to handle. Hewlett-Packard has developed a software solution
to this problem called HP DirectModel. DirectModel is a toolkit that application
developers, like The MSC.Software Corporation, can use to allow their
applications to visualize with very large CAD and CAE datasets. MSC is
working with HP to apply DirectModel technology in MSC/SuperModel, an
application that is designed to work with large models. By working together
HP and MSC are bringing you software and hardware that will help you do
your job easier, faster, and better.
MSC AEROSPACE
SOLUTIONS: OPTIMIZING THE DESIGN-TO-CERTIFICATION PROCESS, (Acrobat
1.37MB) #197, 12 pgs.
Ken Blakely--The MSC.Software Corporation
ABSTRACT: This paper
describes MSC's solutions for optimizing our aerospace customers' structural
design-to-certification processes. It describes the strategies, software,
and services we offer, many provided by working in close partnership with
key aerospace companies. These solutions are designed to optimize the
processes by improving the time to market and decreasing the costs. In
addition, the presentation shows our current and future aerospace solutions
plan.
MSC PRODUCT
UPDATE, (Acrobat 1.32MB) #597, 14 pgs., color
Mark Kenyon, Bob Jones, Greg Sikes and Alan Caserio--The MSC.Software
Corporation
ABSTRACT: This paper
describes the status of MSC products, focusing on the new features in
the latest versions. This information is current as of October 1997.
PRODUCT
SIMULATION INTEGRATION FOR STRUCTURES, (Acrobat 30KB) #397, 6 pgs.
H. Martin Prather, Jr.--The Boeing Commercial Airplane Group (BCAG)
Raymond A. Amador--The MSC.Software Corporation
ABSTRACT: The Product
Simulation Integration (PSI) Structures project is under way in BCAG
to reduce costs and cycle time in the design, analysis, and support
of commercial airplanes. The objective of the PSI project is to define
and enhance the processes, methods, and tools to integrate structural
product simulation with structural product definition. This includes
automated engineering analysis as an integral component of the product
definition. Subprojects have been defined and we are working selected
topics toward accomplishing the objectives of the PSI for BCAG Structures.
Formalized integration activities have also been identified to support
the PSI subprojects through their technology life cycle.
REDEFINING
THE PROCESS OF AIRFRAME FINITE ELEMENT MODEL DEVELOPMENT USING MSC/SUPERMODEL,
(Acrobat 1.37MB) #497, 15 pgs, color
Michael Farley-- Raytheon E-Systems Waco
ABSTRACT: To develop,
in less than one year, an MSC/NASTRAN 747SP finite element model from
scratch to support the SOFIA (Stratospheric Observatory for Infrared
Astronomy) program is an effort requiring significant planning.
Model development is facilitated
by dividing the airframe structure into submodels enabling parallel
development of each submodel within separate MSC/PATRAN databases. Directing
this effort requires configuration control and file management to maintain
the overall pedigree of the model, which includes section properties,
history files, drawings used and assumptions made. This paper discusses
how MSC/SuperModel is being used to redefine airframe finite element
modeling at Raytheon E-Systems Waco.
STRUCTURAL
ANALYSIS FOR THE 21ST CENTURY, (Acrobat 1.37MB) #297, 14
pgs.
Brian P. Oldfield--British Aerospace
ABSTRACT: Structural
analysis tools have progressed to a stage where they are increasingly
used in everyday engineering applications. Within the aircraft industry,
the application has mainly concentrated on providing an insight into both
detail and overall structural behaviour and to aid design decisions via
optimisation. The testing of structures still forms a large part of the
design and qualification process, with analysis providing additional information
to support these activities. We
are now moving to an era where detailed simulation of a structure is required,
such that testing programmes can be significantly reduced. To meet this
requirement, results must be produced with extremely high levels of confidence
and shown to be representative of the real structure. This paper considers
some of the current capabilities and future developments in analysis technology
which will be required to move towards this environment of full simulation,
and also considers some of the associated problems and risks.
Space
A2100
COMMERCIAL SATELLITES INTEGRATED MECHANICAL ANALYSIS, (Acrobat 235KB)
#1797, 14 pgs.
Vince M. Stephens--Lockheed Martin Missiles & Space
ABSTRACT: The commercial
satellite industry drive towards reducing delivery time requires that
mechanical analyses implement production line type methodologies. Analysis
of multiple satellites is facilitated by augmenting MSC/NASTRAN with
software that automates FEM checkout, sorts multiple load case stresses/forces,
prepares reduced coupled loads models, and facilitates pre-environmental
test analyses.
EFFORTS
TOWARDS AN EFFECTIVE STRUCTURAL DESIGN IN ARIANE 5 STRUCTURES DEVELOPMENT,
(Acrobat 1.03MB) #1697, 14 pgs.
Joaquin Martín--Construcciones Aeronauticas, Madrid, Spain
ABSTRACT: The continuous
striving for designing quick and efficiently optimum structures obliges
to define analyses processes guaranteeing that all the structure details
are sized to resist the most critical conditions they may encounter. In
response to this need, specific tools have been developed at CASA Space
Division to design structures of the Upper Stage of the ARIANE 5 Launch
Vehicle. The use of these tools guarantees that none of all possible loading
conditions and structure details is left unattended.
INTERNATIONAL
SPACE STATION THERMALLY INDUCED SOLAR ARRAY BASE LOADS, (Acrobat 409KB)
#1997, 14 pgs.
Tarun Ghosh--Boeing North American, Inc.
ABSTRACT: As the International
Space Station orbits around the earth, it goes through sunlight and the
shadow of the earth. This causes temperature variations in the station
as a function of time and position. The solar arrays are very sensitive
to temperature variations and generate vibratory motion which can lead
to accelerations in the racks where even very small accelerations are
a concern. One method of computing the rack accelerations is to first
determine the solar array base loads and then use transfer functions to
obtain the rack accelerations. Finite element codes that allow thermal
loads are meant for structures where support loads are generated from
over restraint. These codes are not meant for structures, such as solar
arrays, where support loads are due to inertia forces generated by thermal
loading. The purpose of this paper is to show a simple method of obtaining
solar array base forces when there is free thermal expansion. In such
a case, the boundary forces are primarily from inertia forces and drag
forces are simply negligible. The inertia forces are a product of mass
and acceleration. The acceleration is estimated from thermal displacements
accurately computed by MSC/NASTRAN. The mode superposition approach using
MSC/NASTRAN is used to include any drag effect of damping and the influence
of vibratory modes. The net result is an efficient process that gives
reasonable results.
TRANSIENT
ANALYSIS OF THERMAL PROTECTION SYSTEM FOR X-33 VEHICLE USING MSC/NASTRAN,
(Acrobat 619KB) #1897, 10 pgs.
H. Miura, M. Chargin, J. Bowles and T. Tam--NASA Ames Research Center
Dan Chu and Mike Chainyk--MacNeal Schwendler Corporation
ABSTRACT: X-33 is
an advanced technology demonstrator aircraft for the reusable launch
vehicle (RLV) design. The thermal protection system (TPS) for the X-33
is composed of complex layers of materials to protect internal components,
while withstanding severe external temperatures induced by aerodynamic
heating during high speed flight. It also serves as the vehicle aeroshell
in some regions using a stand-off design. MSC/NASTRAN thermal analysis
capability was used to predict transient temperature distribution (within
the TPS) throughout a mission, from launch through the cool-off period
after landing.
In this paper, a typical
analysis model, representing a point on the aircraft where the liquid
oxygen tank is closest to the outer mold line, is described. The maximum
temperature difference between the outer mold line and the internal
surface of the liquid oxygen tank can exceed 1500°F. One dimensional
thermal models are used to select the materials and determine the thickness
of each layer for minimum weight while insuring that all materials remain
within the allowable temperature range. The purpose of working with
three dimensional (3D) comprehensive models using MSC/NASTRAN is to
assess the 3D radiation effects and the thermal conduction heat shorts
of the support fixtures.
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