1998 Americas Users' Conference
The conference proceedings for
the 1998 Americas Users' Conference are now available on-line in Adobe Acrobat
PDF format. The papers have been categorized by topic.
Categories
Aircraft
MSC/FLIGHT
LOADS AND DYNAMICS VERSION 1 (Acrobat 237K) #1198, 8 pgs.
Greg Sikes and Douglas J. Neill--The MacNeal-Schwendler Corporation
ABSTRACT: For the
past year, the MacNeal-Schwendler Corporation (MSC) has been actively
developing solutions to the challenges faced by our customers in the
area of external loads and aerodynamic response. Through strategic partnerships
with the world's leading civilian and military air vehicle manufactures,
MSC has developed an in-depth understanding of our customers' needs.
These efforts have lead to the development of an integrated, process-driven
external loads and dynamics system called MSC/FlightLoads and Dynamics.
PARTICULARITIES
OF SINGLE SHEAR PIN JOINTS MODELING FOR MSC/NASTRAN (Acrobat 3.5MB)
#3898, 12 pgs.
Adrian Viisoreanu--Boeing Commercial Airplane Group
Kris Wadolkowski--Aerostructures, Inc.
ABSTRACT: Inspired
from the analysis of aircraft engine mount fittings, this paper presents
techniques applicable to the solid modeling of single shear pin joints
in MSC/NASTRAN. A parametric study describes the influence of some joint
geometry parameters on the stress and bearing load distribution along
the pin length. The effect of the residual stress induced by the bushing
interference fit is also considered.
POSTPROCESSOR
FOR AUTOMATIC MODE IDENTIFICATION FOR MSC/NASTRAN STRUCTURAL DYNAMIC SOLUTIONS
WITH EMPHASIS ON AIRCRAFT FLUTTER APPLICATIONS (Acrobat 33K) #1498,
4 pgs.
Emil Suciu--Raytheon Systems Company
Joseph Buck--DeHavilland Inc.,Ontario
ABSTRACT: A practical
procedure and postprocessor FORTRAN program which sums strain energies
for an aircraft structure, elastic element by elastic element for each
component as outputted by MSC/NASTRAN Solution 103 or Solutions 145
and 146 is described and an example is provided showing an output table
of strain energies for a hybrid finite element model of a twin turboprop
aircraft and comparison with a few plotted mode shapes. The application
of the procedure to the .f06 output of one of the structural dynamic
solutions results in automatic naming of the analytical modes of vibration,
a powerful aid for the flutter analyst.
THEORETICAL
VALIDATION AND DESIGN APPLICATION OF MSC/NASTRAN SNAP-THROUGH BUCKLING
CAPABILITY
(Acrobat 293K) #1598, 15 pgs.
Dr. M.M. Moharir--The Aerostructures Corporation
ABSTRACT: MSC/NASTRAN's
Snap-Through Buckling capability is validated using a closed form solution
based on the large displacement theory and the nonlinear eigenvalue
extraction procedure for flat and "slightly" curved thin plates.
Excellent correlation is observed for displacements, stresses, and buckling
loads at Snap-Through. The capability is used to design and analyze
the leading edge of a large commercial airplane.
THREE
DIMENSIONAL MODEL OF AN ARRAY OF PANEL BAYS INCORPORATING PRETENSIONED
FASTENERS, PRECOMPRESSED FASTENER SURROUNDINGS, SHELL-TO-SOLID AND BAY-TO-BAY
NASTRAN INTERFACE CONNECTORS (Acrobat 1.0MB), #3098, 21 pgs.
Steven Basic--Boeing Commercial Airplane Group
ABSTRACT: This paper
extends applicability of the finite element method to the analysis of
interaction between the main components of a panel bay (chords, webs
and stiffeners) and an array of elastic fasteners on elastic plate-foundations.
The pre-tensioned fasteners and the pre-compressed fastener-surroundings
of this model are three-dimensional fine-mesh-solid islands that are
integrated into the rest of the plate-element structure using the new
shell-to-solid Nastran Interface Connectors.
The outer cylinder mesh nodes
of fasteners are connected to the fastener-bore mesh nodes with an array
of substantially non-linear radial gap elements, whose radial stiffness
may have two magnitudes.
The first run of the model will be made with the least possible radial
stiffness of the gap elements. The main objective of this run is determination
of the maximum stain gauge element stresses. The strain gauge elements
are located at the outermost and innermost plate-to-hole edges.
The second run of the model
will be made with a relatively high magnitude of the gap element radial
stiffness generating a 'Filled Hole' mesh . The main objective of the
'Filled Hole' mesh is the reference stress determination at the hole
edge strain gauge elements.
By definition, the maximum
plate-to-hole edges to the reference stress ratios are the stress concentration
factors 'Kt max' and 'Kt mm' at the outermost and innermost edges of
the plates. This increase of the tensile and hoop stresses, relative
to an inelastic fastener concept incorporating 'Kt mean' at the central
lines of plates, is caused by an additional bearing stress component
due to the fastener-to-fastened plate interference, in their elastically
deformed configuration.
The Load Transfer Factor
(LTF) will be calculated also in two stages. The first stage will be
the same as that of the existing inelastic fastener methodology, i.e.
the logarithmic magnitude of the LTF (that was substantiated with numerous
tests) will be determined for a given ratio between bearing stress-flange
thickness and the tensile stress -fastener diameter products.
Within the second stage a correction factor, to be applied to the LTF,
will be established. This smaller than '1' correction factor will be
found from increments of the the mean integral and the maximum 'Kt max'
values of this model using the allowable stress for varying 'Kt', as
obtainable from the Kinetic Theory of Solids and Reference [7].
Automotive
ADVANCED
MODE SHAPE IDENTIFICATION METHOD FOR AUTOMOTIVE APPLICATION VIA MODAL
KINETIC ENERGY PLOTS ASSISTED BY NUMBEROUS PRINTED OUTPUTS (Acrobat
488K) #1898, 17 pgs.
Manfred Wamsler-- Daimler-Benz AG
Ted Rose--The MacNeal-Schwendler Corporation
ABSTRACT: Design optimization
procedures of full-vehicle simulation models - such a procedure as shown
in this paper - require a very fast and reliable mode shape identification.
Just because these simulation models necessarily contain a lot of large
concentrated masses and mass moments of inertia, e.g., engine, gear,
differential, car wheels, steering wheel, mufflers, airbags, and reduced
masses from superelement processing, to name just a few, the kinetic
energy method is especially destined to accomplish this task. In the
present paper, a graphical Modal Kinetic Energy evaluation technique
is described in detail. Moreover, the modal kinetic energy plots are
a means to investigate the structure's eigenbevior in the low-frequency
range, e.g., to see where dynamic vibration absorbers have to be attached
and where bushings, and instrumentation for modal testing have to be
placed. In summary, the presented graphs make even the most complicated
subjects clear and provide the dynamicist with information he can use
to achieve a better design quickly. The prints of significant values
indicate the degree of coupling between energies in rotational and translational
direction per mode and the energy portions of the physical residual
chassis structure and the energy portions of appended body and subframe
superelements. Representative applications for mode shape identification
in automotive engineering, V70, are presented extensively in order to
demonstrate the strength of the method. Surely, there are many other
applications in the engineering structural analysis field where the
advanced mode shape identification method will play key roles.
IMPROVED
IDENTIFICATION OF CONTRIBUTING MODES IN SUPERELEMENT MODAL FREQUENCY RESPONSE
ANALYSIS, V70 (Acrobat 325K) #2098, 15 pgs.
Manfred Wamsler-- Daimler-Benz AG
Ted Rose--The MacNeal-Schwendler Corporation
ABSTRACT: In parallel
with experimental methods, modern-day cars are designed by advanced
dynamic analyses using the Finite Element Method. These analyses help
identify components sensitive to vibrations that could possibly lead
to deterioration of ride comfort and safety. For correct simulation
of the real dynamic behavior of a car all parts relevant to vibrations
have to be taken into consideration when assembling a full-vehicle simulation
model. Since this model contains many viscous dampers, such as shock
absorbers, the steering damper, and several hydro-mounts for the engine/gear
unit and the rear-axle support - when the modal transformation is applied
for reduction purposes - the generalized damping matrix is not diagonal;
that is, the modal equations remain coupled by the damping coefficients.
Consequently, the dynamic response is composed of various contributions
resulting from eigenvectors. Knowing the contributions from each mode
shape is a very important requirement for taking suitable measures in
order to decrease obnoxious vibration amplitudes, i.e., the modal contributors
are a means of finding suitable locations for modifications aimed at
improving the structure's dynamics. It is worthwhile to notice, that
by the use of the presented procedure innovative redesigns may be found
by the analyst which the automatic stuctural optimizers are never able
to find. Guidelines on how to influence contributing modes in order
to decrease high resonance peaks are given along with a V70 SOL 111
DMAP alter for the identification of contributing modes.
Civil
PVC SEWER
SYSTEM SEISMIC ANALYSIS MADE PRACTICAL (Acrobat 520K) #0298,
14 pgs.
Hirokazu Nishiura--Sekisui Chemical Co., Ltd.
Eiichi Satoh--SC-Japan
David Bremmer--The MacNeal-Schwendler Corporation
ABSTRACT: MSC is
announcing a new business offering based upon a breakthrough technology.
MSC has developed a means by which design engineers or occasional CAE
software users can reliably perform complex engineering analysis with
the same resultant quality as do the dedicated analysis experts. This
breakthrough technology captures the expert's engineering knowledge
and specific process solution methodologies to enable and guide the
novice. Now CAE can readily enhance the design processes where it was
previously unavailable. Most importantly, large productivity gains are
realized in the design process. The first practical test case for this
technology was to solve the problem that prevented Sekisui Chemical
Company from deploying their analysis methods for creating earthquake
resistant designs.
Sekisui Chemical Co. has
developed new earthquake resistant PVC pipeline components. To support
this new materials technology, complex nonlinear FEA models for evaluating
system performance under earthquake loading were developed. The challenge
now is to integrate for practical use, the performance analysis methods
into the design process for system layout.Sekisui wishes to provide
earthquake resistance checks for all new drainpipe system designs.
Modeling of one sewer system
layout, including selected earthquake loads and nonlinear soil behavior
has required an average of 40-days for expert analysts. A radical departure
from the traditional FEA modeling tool set is required to enable non-FEA-expert
design engineers to use the developed sewer system analysis methodology.
A sewer system modeling
application was written in the form of extended HTML drive pages similar
to web pages. Automation functions were produced by capturing MSC/PATRAN
session files from the manual analysis process as performed by an expert.
The special application written for Sekisui will reduce the effort of
producing sewer system analysis models from 40-days, to a matter of
hours. Furthermore, it will allow design engineers who are not FEA,
earthquake engineering, or soil engineering experts to perform the job
with expert quality results.
Composites
COMPOSITE
DESIGN EXPERIENCE USING MSC NASTRAN FOR THE HYDRODYNAMIC FAIRINGS OF A
NEW SUBMERSIBLE (Acrobat 1.2 MB) #1698, 22 pgs
Dr. E. Thomas Moyer Jr., Dr. Richard Cobb and Mr. Kim Grubbs--Analysis
and Technology Inc.
Dr. William Gordon--Northrop-Grumman Corporation, Oceanic Systems
ABSTRACT: This paper
details our recent experiences designing the fairings for a new submersible
vehicle being constructed. A unique composite material design approach
was chosen to meet challenging structural requirements while minimizing
weight. Analysis examples include material selection decisions, laminate
design tradeoff studies, modeling of bolted joints, establishment of
material allowables and global/local analysis approaches.
Design/Manufacturing Methods
APPLYING
MSC/PATRAN AND MSC/NASTRAN TO IMPROVE THE DESIGN PERFORMANCE OF LARGE
BULK MATERIALS HANDLING MACHINES (Acrobat 33K) #3798, 9 pgs.
R.C. Morgan, Dr. S. Loganathan, and Dr. F. Gatto--BHP Engineering Pty
Ltd.
ABSTRACT: Bulk materials
handling machines such as stackers, bucket wheel reclaimers, ship loaders
and ship unloaders are complex moving structures with onerous loading
and service conditions. Due to such factors there is the potential for
many failure modes and problem areas on these machines.
Machines are normally purpose
designed for the particular application at a port, mine or industrial
facility. In the current environment, high reliability standards are
required in order to provide operational security for business and safety
to personnel.
Dynamic, buckling and non
linear behaviour of such structures can all contribute to failures and
operational problems. Hence a sophisticated analysis and modelling tool
is required in order to provide adequate representation under service
conditions.
Due to the complexity and
size of these structures, models with large numbers of degrees of freedom
are required for analysis. It was previously very time consuming and
costly to carry out such work, putting it out of the realms of commercial
application. However the compatibility of MSC/PATRAN with CAD systems
and the ease of building large models, together with recent developments
in the efficiency of the solvers in MSC/NASTRAN, opens new frontiers
for engineers to critically examine the design of new structures before
they are built.
Similarly, with the application
of MSC/PATRAN and MSC/NASTRAN, existing machines can be critically examined
and cost effective life extension strategies developed to deliver major
economic benefits to owners.
MODAL
QUALITY. THE KEY TO CAD/CAM/CAE INTEROPERABILITY (Acrobat 195K) #2398,
12 pgs.
Dan McKenney--International TechneGroup Incorporated
ABSTRACT: Today 3D
CAD Models are driving a growing number of downstream CAD/CAM/CAE applications.
When those involved in Finite Element Analysis, Rapid prototyping, Numerical
Control, and Data Exchange functions can work directly with the original,
clean CAD model the results are significant boosts to product quality,
production costs, and time to market.
Unfortunately a growing number
of CAD models contain hidden errors or anomalies requiring the models
to be reworked by the downstream user. Studies show that FEA users,
for example, are spending as much as 70% of their time fixing CAD models.
Similarly, other downstream users are wasting a significant amount of
time correcting CAD model errors as well.
This presentation will discuss
the Model Quality concept and demonstrate how these problems can be
easily isolated and identified. It will show how implementing a Model
Quality program can slash or eliminate the need for the downstream users
to fix problem CAD files. We will detail how CAD/CAM/CAE users at any
level can and should begin implementing such a program. While the presentation
will provide a solid overview, it will highlight the CAE interests of
the audience.
RAPID
OPTO-MECHANICAL DESIGN USING PRO/E, MSC/NASTRAN AND CODE V. (Acrobat
683K) #2198, 10 pgs.
Victor J. Wagner, Richard Malnory, and K. Scott. Ellis--Raytheon Missile
Systems Company
ABSTRACT: The mechanical
design of Optical systems (Opto-Mechanical Design) is typically concerned
with minimizing the impact of the mechanical structure and environments
on optical performance. Structurally insignificant loads may induce
unacceptable motion and/or distortion into the optical elements, which
are summed along the optical path resulting in total image blur and
error. Optical system designs are therefore extremely sensitive to mounting
configurations and structural dynamic characteristics of the mechanical
system. A process for efficient design investigation is discussed that
provides rapid system and individual optical element error predictions
for mechanical system design. Topics include discussions of fundamental
Opto-Mechanical design considerations, Pro/E model modification to facilitate
automesh techniques, various automesh approaches using MSC/PATRAN and
Pro/Engineer, tet4 vs tet10 element performance and accuracy with MSC/NASTRAN,
Line Of Sight (LOS) error predictions, and Zernike polynomial calculations
for optical surface aberrations using the MSC/OPOLY utility and Code
V.
RECENT
ADVANCES IN MSC/PATRAN PRE-PROCESSING SOFTWARE ALLOWS MODELING OF COMPLEX
AUTOMOTIVE LAMP DESIGNS (Acrobat 618K) #3398, 9 pgs.
William I. Moore, Eric S. Donovan, and Christopher R. Powers-- Delphi
Interior and Lighting Systems
ABSTRACT: Advances
in automotive lamp designs have resulted in a more compact, aerodynamic
packaging and the use of less expensive plastic materials for the lens
and housing. The smaller packaging and lower melting point of plastics
have increased the need for a predictive tool for simulating the lamp
temperature rise under operating conditions. The modeling of lamps requires
sophisticated analysis tools incorporating computational fluid dynamics
and specular radiation. These tools use a finite element method to solve
a system of non-linear equations for velocity, pressure and temperature.
In addition to the non-linearity, the complex parabolic shape of the
lamp reflector and lens requires very powerful mesh generation capability
in order to produce an adequately refined mesh. The lamp modeling is
performed in two stages. First the model is generated by importing CAD
data from Pro/ENGINEER or Unigraphics into the MSC/PATRAN pre-processor.
The surfaces are then meshed with triangular elements which are used
as a seed for creating the air volume and lamp solid wall tetrahedral
element meshes. The use of the new MSC/PATRAN hybrid tetrahedral mesher
has enabled the creation of very complex 3D element meshes to represent
fluid volumes with several hundred thousand elements. MSC/PATRAN has
become a common pre/post-processor for many analysis codes because of
the open CAE environment, advanced meshing capability, ease of applying
loads and boundary conditions and effective post-processing capability
for displaying results.
DMAP
A DMAP
ALTER TO CALCULATE THE CONTRIBUTIONS OF INDIVIDUAL MODES IN A MODAL COMPLEX
EIGENVALUE OR FREQUENCY RESPONSE SOLUTION(Acrobat 358K) #1798, 9 pgs.
Ted Rose Manager--MSC
ABSTRACT: In this
paper, a DMAP alter is presented which will calculate and print the
Contributions of individual modes to a solution at user-selected locations.
The alter allows you to chose from several different formats for the
output: Magnitude/phase, real/imaginary, projection on solution, fraction
of solution, and others.
MDI/ADAMS-MSC/NASTRAN
INTEGRATION USING COMPONENT MODE SYNTHESIS (Acrobat 98K) #1998, 10
pgs.
Gisli Ottarson--Mechanical
Dynamics Inc.
Greg Moore--The MacNeal-Schwendler Corporation
Diego Minen--Mechanical Dynamics Inc., Italy
ABSTRACT: Improvements
continue to be made in the area of MSC/NASTRAN-MDI/ADAMS coupling, with
the status of the jointly developed DMAP/translator-based interface
described herein. Although the current implementation still relies on
a combined DMAP alter and an external utility, the results of this phase
of development include a number of enhancements which greatly improve
ease-of-use, performance, and results quality. This paper briefly describes
the motivation for the current work, outlines improvements made to the
component modes-based interface, and concludes with an example of the
new interface's use in automotive vehicle design.
Fatigue Analysis
FINITE
ELEMENT BASED FATIGUE ANALYSIS (Acrobat 13.3 MB) #1298, 15 pgs.
Dr. NWM Bishop and Alan Caserio--MSC
ABSTRACT: Fatigue
analysis procedures for the design of modern structures rely on techniques,
which have been developed over the last 100 years or so. The first accepted
technique was the S-N or stress-life method generally given credit to
the German August Woehler for his systematic tests done on railway axles
in the 1870's. Initially these techniques were relatively simple procedures,
which compared measured constant amplitude stresses (from prototype
tests) with material data from test coupons. These techniques have become
progressively more sophisticated with the introduction of strain based
techniques to deal with local plasticity effects. Nowadays, variable
stress responses can be dealt with. Furthermore, techniques exist to
predict how fast a crack will grow through a component, instead of the
more limited capability to simply predict the time to failure. Even
more recently techniques have been introduced to deal with the occurrence
of stresses in more than one principal direction (multi-axial fatigue)
and to deal with vibrating structures where responses are predicted
as PSD's (Power Spectral Density's) of stress. Even more recently researchers
have addressed the requirements for the design of specific components
such as spot welds. All of these techniques were developed outside of
the Finite Element environment. However, they have now been implanted
into many FE based analysis programs, the best known of which is MSCFATIGUE.
The FE environment introduces additional considerations relating to
how input data is processed and how fatigue life, or damage, results
are post processed. This paper will deal with the issues associated
with how fatigue techniques can be incorporated into the FE environment.
Modern examples of FE based fatigue design will be included.
VIBRATION
FATIGUE ANALYSIS IN THE FINITE ELEMENT ENVIRONMENT (Acrobat 4.3 MB)
#1398, 15 pgs.
Dr. Neil Bishop and Alan Caserio--MSC
ABSTRACT: Fatigue
damage is traditionally determined from time signals of loading, usually
in the form of stress or strain. However, there are many design scenarios
when the loading, or fatigue damage process, cannot easily be defined
using time signals. In these cases the design engineer usually has to
use a test based approach to evaluate the fatigue life of his structure
or component. Or, alternatively, a frequency based fatigue calculation
can be utilized where the loading and response are categorised using
Power Spectral Density (PSD) functions.
One very important design
problem, which falls into this category, is that of acoustic fatigue.
However, there are also many other situations where structures are subjected
to a random form of loading such as wing flutter, landing gear runway
profiles, engine vibrations and so on. All of these situations can be
analysed using new fatigue life estimation techniques now incorporated
in MSC/FATIGUE.
The theory of random vibration
fatigue has seen a number of important developments over the last fifteen
years. The authors have been personally involved in developing new fatigue
analysis theories and structural analysis techniques in the frequency
domain. More recently this work has focused on the link with Finite
Element Analysis (FEA) because of the powerful design opportunities
which this creates. The work has found many important practical applications.
This paper will provide a state of the art perspective of random vibration
fatigue technology. A number of design applications will be presented.
General Stress Analysis
APPLYING
VIRTUAL REALITY TECHNOLOGIES TO THE INTERACTIVE STRESS ANALYSIS OF A TRACTOR
LIFT ARM (Acrobat 455K) #0198 , 15 pgs.
Michael J. Ryken, and Dr. Judy M. Vance-- Iowa State University
ABSTRACT: The objective
of this research is to examine the challenges of applying virtual reality
techniques to the interactive stress analysis of a tractor lift arm.
NURBS-based free form deformation, finite element analysis, sensitivity
analysis, collision detection, and virtual reality are combined to create
an interactive environment for designers to view and modify part shape,
evaluate the resulting stresses, and check for interference of the new
part shape and surrounding parts in real-time. These methods are implemented
using a surround screen virtual environment where the part of interest
and associated geometry surrounding that part are displayed together
using stereo projection to provide a three-dimensional view of the assembly.
DIRECT
OR ITERATIVE? A DILEMMA FOR THE USER (Acrobat 33K) #2698, 8 pgs.
Petra Poschmann, Louis Komzsik and Stefan Mayer--The MacNeal-Schwendler
Corporation
ABSTRACT: The subject
of this paper is the comparison of Direct and Iterative solvers in the
Solution of large Finite Element Problems with MSC/NASTRAN. The results
of such a comparison vary based on problem type and with new developments
in both the direct and iterative solution techniques. This paper gives
the current state of this comparison with MSC/NASTRAN V70.5.
Experiences gained in the
past show that analysts are hesitant to use the iterative solver because
the direct sparse solver has been in MSC/NASTRAN from the beginning,
is very robust and has gone through several optimization phases. MSC's
direct sparse solver has very low memory requirements, a very efficient
out-of-core logic and very good re-ordering techniques.
The iterative solver, on
the other hand, was first delivered only early in this decade. It has
since been improved significantly by adding more and better preconditioning
techniques, the latest one being BIC (Block Incomplete Cholesky) preconditioning
which was introduced in V69 . Many clients started to use it for 3-D
models and have reported positive results. More recently, in MSC/NASTRAN
V70.5 the memory management and spill logic for the BIC preconditioner
of the iterative solver have been improved significantly, particularly
for jobs where the solution cannot be done completely in-core.
We will briefly discuss the
methods used for the direct and iterative solvers in MSC/NASTRAN, the
effects of new re-ordering schemes in the direct solver and the effects
of the BIC preconditioning technique in the iterative solver. Moreover,
we will present performance results for large models involving different
types of elements to give guidelines on where the advantages of each
solver lie and when is it more beneficial to use one solver over the
other. For example, for models built from 2D elements it is always recommended
to use the direct solver while for models of 3D elements the iterative
solver should be preferred. Other issues like memory and disk space
requirements and multiple load cases will also be discussed. The focus
of the paper is on linear static analysis.
GLOBAL-TO-LOCAL
ANALYSIS WITHOUT USING SUPERELEMENTS (Acrobat 504K) #2598, 13 pgs.
Klaus Otto Schwarzmeier-- Empresa Brasileira de Aeronáutica S/A
ABSTRACT: Detail analysis
of a structure in general is a problem at least workful. Frequently
this type of analysis requires very refined finite elements meshes being
unfeasible to include all regions of interest in an unique model. This
work can be simplified when we substitute the unique model by a set
of interrelated models. We consider in the methodology presented in
this paper, one model called primary model to analyze the global
behavior of the structure and some other models, the secondary models,
to do the detail analysis of some regions based on the results of the
primary model analysis. The technique presented here does not use the
Superelements feature of MSC/NASTRAN, neither mesh transitions. Therefore,
it can be easy used with MSC/NASTRAN for Windows. The use of this technique
by means of MSC/PATRAN will also be discussed.
NONLINEAR
SIMULATION OF A LEVER MECHANISM (4.1 MB) #0398, 14 pgs.
Sergio E. Adeff--The MacNeal-Schwendler Corporation
ABSTRACT: Many device
designs include shaped lever mechanisms that must function reliably
through a variety of load conditions. A lever shape is often optimized
to carry out their function with optimal use of the material and processes
involved in their fabrication. Levers are present in all types of devices,
commonly in computer hard drives, car engines, airplane control mechanisms,
medical instruments, et cetera. The design discussed in this paper is
a hypothetical yet realistic one. The purpose of this work is to serve
as a demonstration and training device for Engineers interested in learning
how to create an adequate model and carry out complex calculations involving
large displacements and contact between rigid surfaces and a three-dimensional
representation of the deformable bodies of two levers and other parts
of a mechanism. The model will be available to any interested party
in the form of an MSC/PATRAN database [1] with the MSC/ADVANCED FEA
preference [2] in the World Wide Web. The paper focuses on one aspect
of the more general analysis required for a complete design, namely
the calculation of stress and strain distributions, particularly in
areas of contact and impact, nonelastic deformations, velocities, and
driving and reaction forces under transient conditions. Problems of
convergence often faced when doing a nonlinear analysis of this type
are also discussed. The design -better understood by looking into figures
in the paper- includes four distinctive pieces, designated as hammer,
trigger, anvil, and band. Both the hammer and trigger are levers pivoting
about fulcrum pins extruded from the anvil. Likewise the hammer and
trigger have each an extruded pin to which the band is tightly attached
pulling the two pieces together. The disposition is such that when the
trigger is actuated, the hyperelastic band first accumulates strain
energy and the hammer remains in place, and then the band suddenly transfers
the stored strain energy to the hammer, which is accelerated and then
impacts a protrusion of the anvil. The hammer cames a seal, which impacts
a stamp lying on the anvil. The stamp undergoes plastic deformation
as a result of the impact.
A PERFORMANCE
COMPARISON OF MSC/NASTRAN V68.2 THROUGH V70.5 ACROSS MULTIPLE HARDWARE
PLATFORMS (Acrobat 228K) #2798, 15 pgs.
Joe Griffin--The MacNeal-Schwendler Corporation
ABSTRACT: There have
been enormous advances in both hardware and software technology in recent
years. This paper illustrates MSC/NASTRAN performance using several
types of analyses with several versions of MSC/NASTRAN on multiple hardware
platforms. The purpose of this paper is to inform users of performance
enhancements, which are a result of these advances in technology.
Optimization
CAD BASED
OPTIMIZATION (Acrobat 98 K) #0498, 10 pgs.
Celso Barcelos-- MacNeal-Schwendler Corporation
ABSTRACT: In one form
or the other one of the primary goals of simulation technology over
the years has been to optimize designs. On the whole this has been a
manual process involving the generation of multiple mathematical models
which have been used to validate a given design, and also to compare
different configurations of a design. Although the use of simulation
techniques has proven to be an invaluable part of the engineering design
cycle they has not yet had the impact everyone desires. In order to
help engineers to shorten the design cycle optimization software has
been added to existing packages. Even with these new technologies we
are still not seeing the kinds of efficiencies that design firms have
hoped for. The reasons for why simulation applications, and FEA in particular,
have not had their fullest impact to obtain optimized designs are long
and varied. Some of these factors include:
- FEA has been hard to
use and therefore has been relegated to just a handful of specialist
rather than mainstream design engineers.
- Optimization technology
itself has been slow to mature.
- The CAD software used
for design, and FEA software used for simulation have been stand-alone
systems which simply don't talk to each other very well.
This paper describes a system
which marries geometric construction tools, simulation software, along
with topology and shape optimization technologies which can be utilized
by engineers early in the design cycle to reduce the time needed to
bring new products to market. By integrating these formerly disparate
functions under one umbrella we have taken a giant step forward to achieve
efficiencies which were unthinkable just a few years ago.
DESIGN
OPTIMIZATION USING HYPERSIZER (Acrobat 5.6MB) #0698, 12 pgs
Craig Collier, Phil Yarrington, and Mark Pickenheim Collier--Research
Corporation
ABSTRACT: This paper
identifies an existing commercial solution that MSC users can benefit
from for automated stress analysis and sizing. The HyperSizer software
is mathematically coupled with MSC/NASTRAN to provide an integrated
solution for quick and accurate design optimization. Though specifically
developed for the aerospace industry, the approach and methods apply
to any industry. A reusable launch vehicle, which contains 7 assemblies,
21 optimization groups, and 203 structural components is used as an
example. MSC/NASTRAN is used as the loads model and the entire plane
is optimized using HyperSizer's analysis methods that range from closed
form, traditional hand calculations repeated every day in industry,
to more advanced panel buckling algorithms. Margin-of-safety reporting
for every possible failure provides the engineer with a powerful insight
into the structural problem. The engineer is able to provide 'real-world'
expertise in the optimization process by interacting with HyperSizer
for designs on the fly.
FE-OPTIM
AND MSC/NASTRAN FOR A FREQUENCY RESPONSE OPTIMIZATION (Acrobat 291K)
#0798, 14 pgs.
Dr. Stefan Döemöek and Andreas von Mach--P+Z Engineering GmbH
Dr. Jürgen Merk--AUDI AG
ABSTRACT: FE-OPTIM,
a software tool developed by P+Z Engineering GmbH, supports the MSC/NASTRAN
optimization (Solution 200) in all its key features. The use and the
benefits of FE-OPTIM, combined with MSC/NASTRAN SOL 200, is demonstrated
on an example of an
AUDI project.
HANDLING
OF WELDS IN SHAPE VECTORS GENERATION FOR FINITE ELEMENT SHAPE OPTIMIZATION
- A CASE STUDY (Acrobat 455K) #2498, 6 pgs.
Murali M.R. Krishna--DANA Corporation
ABSTRACT: Design analysts,
who work with finite element shape optimization, face a daunting task
of handling welds. When the designer wants to find the optimum width
of the leg of a bracket, which is welded to a base rail, the analyst
has to remove the old welds, remodel and re-create new welds after extension
of the bracket, and iterate. This method is not suitable for shape optimization.
A numerical interpolation method based on 'Autodv', has been recommended
to handle welds without remodeling. This method is very effective for
finite element shape optimization. A case study has been given to illustrate
the method using MSC/NASTRAN.
LINEAR
CORRECTION OF BUCKELED PANELS USING SOL 200 (Acrobat 153K) #0998,
20 pgs.
Michael C Kobold--Northrop Grumman Corporation
ABSTRACT: A method
to account for the buckling of skin panels on stiffened shell structures
using MSC/NASTRAN SOL 200 linear static optimization is shown. This
builds on previous work, shows conservatism of the classical manual
methods, and introduces several ways to tackle the problem. The Finite
Element Analysis (FEA) involves the comparison of the use of Design
Optimization (SOL 200) for effective width and thickness changes, to
example A20.4 of Bruhn's text 1 . The Finite Element model
uses a small fuselage section with a height of 50 inches, width of 30
inches. The foundation work for crippling strength calculation software
is provided in an Appendix. This work is applicable to curved shell
buckling issues in its use of empirical data available in the literature.
This method's best implementation will be with p-elements due to their
geometry information. The method has application to general stiffened
curved panel structural analysis.
MSC/CONSTRUCT
- FEATURES AND CAPABILITIES (Acrobat 2.3MB) #0898, 18 pgs.
Dr. Hans Sippel--MSC, Munich
ABSTRACT: For design
engineers and analysts MSC/CONSTRUCT1) provides an exceptionally
fast and easy-to-use, conceptional design tool consisting of two options:
- MSC/CONSTRUCT TOPOLOGY
is the topology optimization option, which distributes material within
a design space envelope based on the optimum load paths.
- MSC/CONSTRUCT SHAPE is
the non-parametric shape optimization option, which homogenizes the
stress distribution (Fully Stressed Design).
Both of these options are
FEM-based and use an efficient optimality criteria technique. In the
optimization cycle MSC/NASTRAN is used as the analysis engine. This
guarantees reliable results and highest performance.
MSC/CONSTRUCT V2.5 was released
in Q3/98. Major highlights are:
1. A graphical user interface
within MSC/PATRAN
2. A restart option
3. High performance improvements which significantly increase the throughput
4. An automatic shape basis vector generation for MSC/NASTRAN's SOL
200 by MSC/CONSTRUCT
Especially items 3. and
4. will be presented by customers' real life examples.
USAGE
OF OPTIMUM USAGE OF OPTIMIZATION TOOLS IN THE DESIGN PROCESS AT BMW
(Acrobat 33 K) #0598, 10 pgs.
Ingo Raasch--BMW AG, Munich
ABSTRACT: The usage
of optimization tools in structural mechanics has a long history at
BMW, and it is very much connected with MSC/NASTRAN. Sizing is a standard
procedure in body design with constraints on static and dynamic response.
Shape optimization with MSC/NASTRAN was an initial success. However,
at present it is performed most often with other programs owing to the
ease-of-use and integration within CAD systems. The definition of shape
vectors is still time consuming in both MSC/NASTRAN and other programs.
Optimality-criteria methods such as MSC/CONSTRUCT SHAPE improved the
ease-of-use, but with a sacrifice in the generality of the objective
and constraints definitions. However, a combination of optimality criteria,
mathematical optimization methods, and automatic shape generation has
proven to be a more general and efficient approach.
Topology optimization is
finally being used in the concept design phase. The definition of the
design space can be accelerated tremendously by using the VOXEL technique
of CAD systems. In this technique, a given volume is filled with cubes
of equal size, in order to estimate the volume or detect component collisions.
These cubes are directly used in the finite element design space definition.
Concept design relies heavily
on beam/shell models with beam cross sections as design variables. However,
given the short time frame for the concept design phase, optimization
is still hampered by the lack of pre/processing tools for the design
model definition and post processing of results, as well as the necessity
for heavy computing resources.
PCL
CUSTOMIZATION
OF WING ANALYSIS (Acrobat 33K) #3698, 7 pgs.
Wang Linjiang--Nanjing University of Aeronautics and Astronautics, PR
China
Matthias Haupt--TU Braunschweig, Germany
ABSTRACT: This article
is concerned about the customization of creating a FEM model of a wing
structure. The row and column method is used to number the structure
parts(ribs, spars, skins), then the property parameters of all parts
can be respectively inputted using the spreadsheet in which data can
be inputted easily and correctly. A PCL(MSC/PATRAN Command Language
under MSC/PATRAN 6.0) code is developed for the customization from constructing
airfoil curves to creating the entire wing FEM model. A zigzag wing
is demonstrated to verify the code. At last a VFW614 wing is analyzed
from creating airfoil curves to the show of stresses that are calculated
using MSC/NASTRAN 68. The results shows that this customization is very
effective and efficient, it makes such a difficult work of creating
a wing FEN model become much easier. This method can likewise be used
to fuselage and other complicated structures.
ENVELOPING
RESULTS OF MULTIPLE LOAD CASES (Acrobat 65K) #3498, 10 pgs.
Victor Genberg--Eastman Kodak Company
Justin Vianese--The MacNeal-Schwendler Corporation
ABSTRACT: Many structures
such as those used in the aerospace and the automotive industry are
subjected to multiple load conditions. Software has been developed to
scale, combine, and sort stresses, forces, and displacements from a
few unit load cases. The procedure saves creating and running many load
cases, requires much less plotting, and prevents errors of omission.
A launch load event of 128 combinations can be analyzed from 7 unit
load cases combined into a single plot. This technology is now available
as MSC/PATRAN shareware.
INTEGRATION
OF "ANLEET" AND "ANVECT" PROGRAMS IN MSC/PATRAN ENVIRONMENT
(Acrobat 130K) #3298, 10 pgs.
Alejandro Andueza--Sercon Consulting Services
Claudio dos Santos Amaral and Alvaro Maia --Petrobrás/Cenpes, Rio
de Janeiro
ABSTRACT: Sercon is
a consulting company committed to offering Finite Element design solutions
to the market. We have a long-term experience in the oilfield market,
offering FEA analysis and design of subsea equipment. Most recently,
as part of a close relationship between Sercon and MSC Brazilian office,
we have also been offering customized solutions to MSC clients.
Petarobrás is one of
the biggest oil companies in the world with an annual revenue of over
20 billion dollars. It is currently committed to developing technology
to extract oil from deep-water. Petrobras has already found oil fields
at depths of over 8000 ft of water.
"Anleet" and "Anvect"
programs are custom tools developed by Petrobras to help it in the design
of special piles and anchors which are used as fixed points of the anchoring
lines of floating production units such as sub-submersibles and FPSO's.
These programs have specific features that MSC/PATRAN is not able to
pre-process in its commercial version. Prior to the development of this
work, Petrobrás took too much time to generate the input deck for
"Anleet" and "Anvect" programs using external programming
in order to modify MSC/PATRAN neutral file.
The purpose of this paper
is to show the integration process developed by Sercon to attend Petrobrás's
requirements using MSC/PATRAN open architecture. As part of the integration
process we have developed specific mesh generators for 3D contact elements
and 3D infinite elements.
We have also developed a
parametric model to help Petrobrás to speed up the optimization
process of the anchor design.
ROLE OF
A CUSTOMIZED MSC/PATRAN INTERFACE IN LOWERING COSTS AND "TIME TO
MARKET"(Acrobat 163K) #2898, 10 pgs.
Anthony J. Scott and Donald A. Traub Owens-Brockway
ABSTRACT: In today's
competitive market, part cost and timely delivery are the main driving
forces. Finite element analysis (FEA) software coupled with custom PCL
can enable companies to rapidly verify how geometry changes in a plastic
container design will affect its mechanical properties. Owens-Brockway
(OB) is in the plastic container market. "Time to market"
is very important to its customers. The faster OB can get a new functional
product into production, the better chance it has of getting ahead of
its competition. One of the biggest concerns in the design of a new
container is top-load capability. OB, through the use of a custom FEA
tool, can determine the best design of a plastic bottle to maximize
the top-load capacity. This will be accomplished by using finite element
analysis software that has been tailored to reduce the set-up time.
FEA has the reputation for being an analyst's tool, as a consequence
many manufacturing companies prefer to construct prototype parts, perform
destructive test, and modify the design based on the results. Major
cost reductions can be realized by eliminating the need for such a prototyping
approach.
Test/Analysis Correlation
DRIVESHAFT
SEAL BOOT FINITE ELEMENT ANALYSIS (Acrobat 98K) #3998, 10 pgs.
Leandro Jaskulski, Leônidas Coutinho, César Franck, and Rubens
Gehlen--ATH - Albarus Transmissões Homocinéticas ltda.
This study registers a finite
element analysis of a seal boot used in constant velocity driveshafts,
that was performed in the MSC/NASTRAN software for Windows NT 4.0 in a
Personal Computer. By this analysis the structure’s behavior was studied
in its work life before construction of the actual prototype.
Analysis was made in existing seal rubber boot, showing good accuracy
level when compared with actual part displacement test results. At first,
critical joint motions were selected to identify the constrains and symmetric
plans. The hyperelastic material was approached to an elastic material
in this first step to apply in a plate element model of the part. Then
the results of general part behavior, like displacements, and contacts
were examined and contrasted with laboratory test reports of the real
part.
Prototype development time can be saved in the design phase since the
part can be improved by this theoretical prediction tool. Failure points
can be predicted by the analysis saving resources such as developing production
tools, making prototypes and testing them to finally detect the items
that have to be improved.
STRUCTURAL
DESIGN OF A GUIDING PLATE IN THE PLASTIC REGION (Acrobat 585K) #2998,
15 pgs.
Fábio L. Amaral dos Anjos, Romulo R. Ripoli, and Marcos Antonio Argentino--debis
humaitá IT Sevices Latin America
ABSTRACT: In order
to study the mounting stresses of a guiding plate which holds the leaf
spring suspension of a bus, a structural finite element analysis, with
MSC/NASTRAN v.70, was conducted. Plasticity and non-linear geometric
effects was considered on the model. The mounting load was evaluated
and experimentaly measured. Results from the finite element model of
the guiding plate were compared to experimental ones. A new geometrical
configuration for the part was suggested and analized. The aim was to
minimize plastic deformation of the material and to reduce the mounting
stresses.
THE USE
OF MSC/NASTRAN SOL200 IN A TEST-ANALYSIS INTEGRATION PROCESS APPLIED TO
CONNECTION-WELD MODELLING. (Acrobat 2.6MB) #2298, 9 pgs.
Tom Van Langenhove--LMS International, Belgium
Dennis Turner-- Matra Bae Dynamics
ABSTRACT: When building
finite element models, a lot of simplifying assumptions and estimates
have to be made. Idealisation, discretisation and parameter evaluation
are all possible error sources. If these models have to be used in lifetime
estimations, optimisation processes or system synthesis computations,
they have to be a valid representation of reality. In this paper it
is discussed how MSC/NASTRAN sol200 is used in the process of validation
and verification of dynamic finite element models. This paper focuses
on a frame support. It shows the different steps taken at both the experimental
and the analytical side and describes the complete process based on
the 'actual' application problems. The main features of this support
frame are the welded joints, the connections between solid and shell
elements and the modeling of a solid base by means of shell elements
with a certain thickness. Using powerful functionality's such as correlation,
sensitivity analysis and physical as well as proportional updating,
a well-correlated FE model is obtained and the welded joints and the
thickness of the base are identified as 'hot spots'.
USING
MSC/MVISION TO SIMPLIFY AND EXPEDITE ACCESS TO AND ANALYSIS OF BENCHMARK
DATA (Acrobat 121K) #1098, 7 pgs.
Kirsten Husak--Raytheon Systems Waco
ABSTRACT: MSC/MVISION
is an extremely flexible database application which can be used to manage
any type of information.
At Raytheon, Waco, MSC/MVISION
is being developed to store data from a major benchmark. A schema is
in development which will enable retrieval of results from any benchmark,
performed on any platform, testing any new software package. When complete,
queries will be possible over all data acquired during a benchmark,
allowing vastly improved assimilation and analysis.
Thermal Analysis
NUMERICAL
MODELLING OF LIGHT TRANSMISSION IN A TEMPERATURE AND STRESS SENSITIVE
OPTICAL ELEMENT (Acrobat 228K) #3198, 12 pgs.
Daniel Wormser, Dr. Yoram Liran, and Yonatan Cohen--Electrooptics Industries
Ltd.,
Dr. Joseph Roitfarb, Dr. Vladimir Kaminsky, and Dr. Shlomo Yanetz--Bar-Ilan
University
ABSTRACT: The subject
of this research is numerical modelling of single pass light transmission
through a general optical component subjected to thermal and structural
loads. The light transmission is calculated numerically for an FE model
considering both the thermal effect on the refractive index, and the
structural distortions of the optical component. The thermal and the
structural analyses of the optical component model are computed using
the MSC/NASTRAN FE software. The results of the MSC/NASTRAN FE analyses
are used as input to the light transmission analysis 'IMU-POST' .
The output light beam is analysed with respect to wave-front deviation
and distortion.
USE OF
FINITE ELEMENT MODEL AND TEMPERATURE MEASUREMENTS FOR REAL TIME CONTROL
OF ACTIVE SURFACE AND POINTING OF A 50 M RADIO TELESCOPE (Acrobat
65K) #3598 12 pgs.
Frank W. Kan and Rajesh S. Rao--Simpson Gumpertz & Heger Inc.
ABSTRACT: The Large
Millimeter Telescope (LMT) is a 50 m diameter radio telescope with an
actively controlled segmented surface to be used for astronomy at millimeter
wave lengths. The specifications call for a surface accuracy of 70 micrometers
RMS and a pointing accuracy of 0.7 arcseconds RMS. This paper evaluates
a proposed approach for computing and correcting in real time the surface
deformations of the primary reflector and the pointing errors of the
telescope due to thermal deformations using a finite element model and
temperature measurements throughout the telescope structure.
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