FEA and CFD: Challenges and Best-Modelling Practices for the Aerospace Industry

The pace of development in the aerospace market is accelerating faster than ever and the role of FEA and CFD is a major part of today's product development processes. One of the major challenges for all analysts in the aerospace industry is in producing solid, coherent analysis to best-practice guidelines in a manner which can show management the true value and benefit of FEA and CFD. This industry-focused workshop brought together analysts from across the aerospace industry to discuss, review and discover best-modelling practices, while highlighting the challenges that all users of analysis, and their management, should be considering.

The event ran in parallel with the Aerospace Design Expo at the Anaheim Conference Center.  The seminar was a compilation of sessions supporting the FEA, CFD, and multi-physics coupling theme. Those in attendance considered this seminar to be a great success.

Fundamentals of FEA

- Brett Soltz, The Aerospace Corporation 

An overview of the finite-element method was given, with particular emphasis on how the quality of a solution is determined by the analysts’ discretization.   Examples were presented that highlight how constraint equations can be used to enforce rotational and displacement compatibility to the  modeling accuracy of fundamental structural shapes.    Recommendations on how to improve model correlation assessments were outlined while techniques for modeling strain gages were presented.

Computational Technologies for Product Life-Cycle Simulations

– Louis Komzsik, UGS

The increasing role of analysis in product life-cycle simulations has become an integral part of product life-cycle management.  Engineering scenarios of life-cycle physical simulations and the analysis of very large, multimillion grid and element problems were discussed.  Computational technologies including graph-theory based computations, large linear systems, robust eigenvalue techniques, and domain decomposition were emphasized while state-of-the-art results from industrial applications using NX NASTRAN were presented.

Air Mass Modeling for Lightweight Structures in Nastran

– Paul Blelloch, ATA Engineering

Air mass has been found to influence the low frequency modal behavior of lightweight aerospace structures such as reflectors.   An example that illustrates how simple methods to smear mass do a poor job of representing the effect of the air mass was presented.   Through a comparison with test data, the MFLUID method in Nastran was shown to do a good job of representing the air mass effect on a spacecraft reflector.  Guidelines for manageable run times in terms of the number of wetted elements were also presented.

Multi-Physics Simulation in Aerospace: A Closer Look at Structural & Flow Induced Multi-Attribute  Analysis

– Juan Betts, LMS

This session provided a closer look at structural & flow induced multi-attribute analysis. It also provided a strong review on aero-acoustics and an evaluation on various approaches to arrive an acceptable solution.

Seven Ways to Evaluate Discretization Error

– Hanson Chang, MSC.Software

Whether you are doing preliminary structural sizing or final detailed stress analysis on aerospace components, finite element analysis is an indispensable tool for you.  But just how accurate is your finite element analysis?  How much discretization error is present in the model?  Are the analysis results good enough or should you spend more time refining the mesh?  This presentation shed light on 7 tricks of the trade that experienced analysts have been using in the industry. These 7 techniques were captured in a handy one-page reference chart and are alphabetized from A thru G for ease of memorization.

How COTS Software Enhances Development of Best Practices in the Aerospace Industry

– David Vaughn, CD-adapco

Goals behind CAE best practices for software tool standardization and interoperability were presented in this session.  These goals include ensuring accuracy on a wide range of problems, having correct answers on a consistent basis, having efficient of design cycle times, and supporting manufacturability.

New CESE Fluid Solver & Fluid/Structure Coupling in LS-DYNA

– Zeng-Chan Zhang, LSTC

                                                                                                                Some non-traditional features of Conservation-Element & Solution-Element (CESE) method and Fluid-Structure Interaction (FSI) strategies were presented, including several fluid and FSI examples. This method (solver) is good for all speed flows, especially for high-speed flows with complex shock patterns.

Breakout Modeling Techniques using Free Body Diagrams

– Paul Eder, Altair Engineering

Detailed part analysis and optimization in the aerospace industry involves the creation of sub-models, or breakout models, extracted from global or internal loads models.  The creation of these sub-models can be difficult and time consuming using traditional methods.  Utilizing Free Body Diagram (FBD) concepts, one can simplify and streamline the understanding, creation and setup of breakout models.  FBDs allow the user to understand load paths and to create free body loads of interest for detailed models as boundary conditions (BCs) within a sub-modeling scheme.  FBD modeling techniques, processes and future technologies were discussed.

Multi-Discipline Design, Analysis, and Optimization Framework for Air Vehicle Development

– Wayne Tanner, Leading Edge Engineering

The concept of function vs. geometry can be used as the center of the development process to enable multi-representations of a product, with multi-levels of fidelity, in an optimization framework outside of the traditional CAE environment.

Progressive Damage & Failure Modeling of Woven Fabric Composites for Aerospace Crashworthiness

– Sandor Becz, ABAQUS

Woven fabric composite materials have found increased usage in aerospace structures due to their light weight and high energy absorption characteristics.  The ability to model these structures accurately during impact simulations is critical to the efficient use of these materials.  A progressive damage and failure model in ABAQUS/Explicit that meet these needs was discussed.

Best Practices in Aerospace FEA Results Synthesis using FEMAP

– Carl Poplawsky, MAYA HTT

Finite element analyses generate huge amount of data. This session offered best practices when using stress processors, grid point force processors, element force processors, modal processors, energy processors, random processors, and sine processors.