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Altair ® OptiStruct ®

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  1. Altair®OptiStruct® Meet Today's Complex Product Development Challenges with Award-Winning Concept Design Technology

  2. But, whereisthe CAD datacomingfrom? CAD ? Final Design • CAD import • Geometrycleanup / repair • Preparegeometryaccordingtomeshrequirements • Meshing, meshqualitychecks • Material, properties (i.e. thickness) • Loads, constraints (boundaryconditions) • Loadstep(s) • Export of FE solver deck • Analysis • Postprocessing

  3. But, whereisthe CAD datacomingfrom? • Chirurgen, die entstellte Gesichter rekonstruieren, müssen handwerklich extrem begabt sein: Fehlende Gesichtsknochen werden per Hand modelliert und an den Patienten angepasst. Eine Methode aus dem Bauwesen verspricht jetzt deutlichen Fortschritt für • die plastische Chirurgie.

  4. The CAE Driven Design Process Situation: Yourprofessorasksyouthefollwing: „Forthegivenstucture I needtohave a new, moreinnovative,andlightersolution. Material propertiesremainthe same, however. Deliverydate: Ifpossible, yesterday …“ ? Topologiyoptimization will helpyou

  5. The CAE Driven Design Process Challenges of the early design phase • What if there are no similar or previous designs to reference? • What if the similar design doesn’t scale for the new configuration? • What if you don’t have experience with this type of design? • What if previous designs were never optimized for weight? • What if you have many load cases? • What if you have limited time to make design changes? • What if your engineering judgment leads you down the wrong path? • …

  6. ... Innovative or„old“ and well knownsolutions ??? The CAE Driven Design Process Challenges of the early design phase In theconceptphasethedesignerhasmaximum design freedom, but minimum design knowledge 80% of the product weight is determined at the concept design stage

  7. The CAE Driven Design Process Howcanweoptimizethe design without knowingthe design in detail?

  8. The CAE Driven Design Process Topology Optimization – Conceptual Design Setup of optimization problem, definition of design constraints Mesh generation, definition of loads and boundary conditions Computation Interpretation of results CAD Design Definition of available package space

  9. Density = 1 Density = 0 E/E0 1 (r/r0)b 1 r/r0 The CAE Driven Design Process Topology optimization – how does it work? (material) intermediate solutions areavoided • Penalization of intermediate densitythrough power lawb> 1.0 • K(r) = r b Kb = 2 ~ 4 • Where K and K represent the penalized and the real stiffness matrix of an element, respectively, r is the density and b the penalization factor which is always greater than 1. SIMP Method (Solid Isotropic Microstructure with Penalty for Intermediate Density, Bendsøe 1989; Zhou and Rozvany 1990)

  10. The CAE Driven Design Process Optimization – how does it work? The Optimization Problem Statement: • Objective(What do I want?) min f(x) also min [max f(x)] • Design Variables (What can I change?) XiL≤ Xi ≤ XiUi =1,2,3,…N • Design Constraints (What performance targets must be met?) gj(x) ≤ 0 j = 1, 2, 3, …, M

  11. Optimization Terminology The CAE Driven Design Process • Design Variables: System parameters that are varied to optimize system performance. • Design Space: selected parts which are designable during optimization process. For example, material in the design space of a topology optimization • Response: Measurement of system performance. • Objective Function:Any response function of the system to be optimized. The response is a function of the design variables. Ex. Mass, Stress, Displacement, Moment of Inertia, Frequency, Center of Gravity, Buckling factor, and etc. • Constraint Functions: Bounds on response functions of the system that need to be satisfied for the design to be acceptable. • Feasible Design: One that satisfies all the constraints. • Infeasible Design: One that violates one or more constraint functions. • Optimum Design: Set of design variables along with the minimized (or maximized) objective function that satisfy all the constraints.

  12. The CAE Driven Design Process Exercise Determine/find a „lightweight“ design (i.e. withmiminummass) The max. model dimension (design space) isgiven i.e. your design proposal (2Dwithconstantthickness, T= 1mm) maybesmallerormaycontainsholes etc. Restriction: Maximum allowedopeningatthetip: +/- 0.07 mm • F=+/- 100 N max. dimension Material: Steel (E, nu) Usingthe max. design space, theopeningatthetipis +/- 0.02 mm max. dimension

  13. The CAE Driven Design Process Exercise File: Clip_2D_geometry/ clip_geometry.iges max. dimension 1. Think aboutyour design proposal … 2. Import the CAD data in CATIA forCATIA import, youmayneed tochangethefileextensionto*.igs max. dimension 3. Buildyour design in CATIA (Makeuse of symmerty) 4. Export your design as *.igesor *.step 5. Import your design in HyperMesh (CAD data)

  14. The CAE Driven Design Process Exercise File: your_design.iges / step 3 6. Youmayneedtocleanupyour geometry 100 N 7. Meshing 2 1,2,3 8. Define Material, Property, SPC and Loads (Forces), LoadStep 100 N 9. Run analysis 10. Postprocessing and documentation

  15. The CAE Driven Design Process Exercise File: your_design.iges / step 10. Postprocessing and documentation yourdecision *seenextslidesformoreinformation on howtomeasure AREA

  16. HyperMeshIntroduction Measure AREA Select elements

  17. The CAE Driven Design Process Topology optimization - Exercise Base design constraints forces Objective: min. Mass / Volume Restrictions: max. allowableopening (displacement) attip: uy=0.07 mm

  18. The CAE Driven Design Process Topology optimization process - Exercise

  19. The CAE Driven Design Process Topology optimization process - Exercise Interpretation of optimizationresults (by 2 studentdesigners) and re-analysis of theirgiven design Design interpretation I Design interpretation II uy=-0.05 mm uy=-0.07 mm

  20. Creates h3d file: *_s1.h3d

  21. Display elementdensities (iso-plot) Useslidertoadjustappropriateddensityvalue (i.e. darkblueelementsdisappear)

  22. Super imposecontourplot of displacements (notethatthedisplacementvaluesshownreferto all elements)

  23. To post-processelementsabovedensitythreshold and corresponding displacementsre-runtheanalysis Based on the last optimizationrun e.g. design_29, theresultsfile will benamed: _rst029_s1.h3d