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Multidisciplinary Design Optimization Activities at CASDE, I I T, Bombay

Multidisciplinary Design Optimization Activities at CASDE, I I T, Bombay. http://www.casde.iitb.ac.in/MDO/activities-at-a-glance.ppt. http://www.casde.iitb.ac.in/MDO/activities-at-a-glance.ppt. MDO@CASDE Over the Years. Aug 1999 - CASDE initiates MDO activities

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Multidisciplinary Design Optimization Activities at CASDE, I I T, Bombay

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  1. Multidisciplinary Design Optimization Activities at CASDE, I I T, Bombay http://www.casde.iitb.ac.in/MDO/activities-at-a-glance.ppt http://www.casde.iitb.ac.in/MDO/activities-at-a-glance.ppt

  2. MDO@CASDE Over the Years • Aug 1999 - CASDE initiates MDO activities • Aug 2000 - First meeting of SIG-MDO • Jan 2001 - Professional Development Course on MDO • Jun 2002 - Second meeting of SIG-MDO, Workshop on MDO • Feb 2003- Third Meeting of SIG-MDO • Sep 2003 - International Conference on MDO

  3. Design / MDO Studies @CASDE • AEW System Level Optimization • Aero-elastic Design of Transport A/C wings • Aircraft Intake (3D-Duct) design • Low Fidelity Analysis • High Fidelity Analysis (CFD)

  4. Design / MDO Studies @CASDE MDO Studies in formative stages • Hypersonic Vehicles - Integrated System Optimization (with DRDL) • Launch Vehicles - Reliability Based Design (with VSSC) • Launch Vehicle – Simultaneous optimization of trajectory & system (with VSSC)

  5. E P H, V, CL H, V WAnt WR LAnt BAnt Qr WRot Wds CD,R WHX CD,H D, T L, W E Design Optimization of AEW User requirements Mission AEW System P, H, V, CL D4 D1 D3 D2 DC Radar Rotodome Heat exchanger Platform

  6. MDO of Transport Aircraft Wing • Stage I : Analysis based on empirical formulae • Stage II : semi-empirical analysis • realistic aerodynamic loading - VLM • simplified structural analysis - EPM • Stage III : Hi-fidelity analysis with aeroelasticity • VLM • FEM - NASTRAN

  7. Cruise for 3000 Km at best range M ≥ 0.74 3 4 Descend to 1500 m 5 Climb to 11000 m at best ROC ≥ 11 m/s Loiter 45 min (Reserve) 6 1 2 7 8 Takeoff at sea level d ≤ 2150 m Land at sea level d ≤ 1220 m MDO of Transport Aircraft Wing – Baseline Problem • ~150 seater aircraft • Mission profile shown • B 737-200 candidate for numerical study

  8. MDO of Transport Aircraft Wing MDO Problem • Simultaneous aerodynamic and structural optimization • variables - wing aerodynamic shape + wing structural sizing • constraints - mission, aerodynamics, structural, aeroelastic Analysis tools • Optimizers : FFSQP / NPSOL (SQP) • Aerodynamic analysis : Vortex Lattice Method (VLM) • Structural analysis : • Medium fidelity – Equivalent Plate Method (EPM) • High fidelity – Finite Element Method (MSC NASTRAN)

  9. Aerodynamic Geometry • Planform • Geometric Pre-twist • Camber • Wing t/c • single sweep, tapered wing • divided into stations • S, AR, ,  y  AR = b2/S  = citp/croot croot citp Wing stations b/2 x MDO of Transport Aircraft Wing

  10. Structural Geometry • Cross-section • Box height • Skin thickness • Spar/ribs • symmetric • front, mid & rear boxes • r1, r2 y A r1 = l1/c r2 = l2/c A A l1 l2 A c x MDO of Transport Aircraft Wing

  11. MDO of Transport Aircraft Wing Function Evaluations • Structural • Stresses (x , y , xy ) • Structural Weight (Wt) • Deformation Function (W(x,y)) / Nodal displacements • Aerodynamic & Mission • CL ,sectional Cl , CDi(VLM) • Mdiv (semi-empirical) & CDo (empirical) • Vstall, , Takeoff & Landing Distance • Ceiling, ROC, Cruise Mach No. • Geometric • Fuel volume (Vf)

  12. MDO of Transport Aircraft Wing Loads • Load case - quasi-static pull-up maneuver • Aerodynamic pressure loads • Engine loads • Inertia Relief • Fuel Weight Inertia Relief • Wing Mass Inertia Relief • Both are distributed as equivalent uniform pressures over wing stations

  13. Aerodynamic Structural W/S AR  i L h/c d/c r1 r2 hroot h’1 h’2 ts Ars System Analysis Structural Cl CL R dto Mdd s Wt Vf Cdo Aerodynamic MDO of Transport Aircraft Wing

  14. Aerodynamic Structural W/S AR  i L h/c d/c r1 r2 hroot h’1 h’2 ts Ars VLM FEM Structural Cl CL R dto Mdd s Wt Vf Cdo Aerodynamic MDO of Transport Aircraft Wing

  15. Aerodynamic Structural W/S AR  i L h/c d/c r1 r2 hroot h’1 h’2 ts Ars VLM FEM Structural Cl CL R dto Mdd s Wt Vf Cdo Aerodynamic MDO of Transport Aircraft Wing

  16. Aerodynamic Structural W/S AR  i L h/c d/c r1 r2 hroot h’1 h’2 ts Ars VLM FEM Structural Cl CL R dto Mdd s Wt Vf Cdo Aerodynamic MDO of Transport Aircraft Wing Fidelity level for Mdd and Cdo ?

  17. MDO of Transport Aircraft of Wing Optimization Framework Architecture INTERFACE History Block Aerodynamics(VLM) Aeroelasticity Iterator Input Processor Optimizer FSQP Structures MSC/ NASTRAN NASTRANInterface Output Processor Analysis Block

  18. MDO of Transport Aircraft Wing • For more information • http://www.casde.iitb.ac.in/MDO/ • Contact : mujumdar@aero.iitb.ac.in

  19. Composite team ADA, Bangalore CFD Centre, IIT Bombay CASDE, IIT Bombay Bring in CFD into Optimization loop Commercial codes? In-house codes? 3D-Duct Design

  20. Entry Exit Location and shape known • Pressure Recovery? • Distortion? • Swirl? Geometry of duct from Entry to Exit ? 3-D Duct DesignDesign Problem in Brief

  21. Y Z X X Duct Centerline • Control / Design Variables • Ym, Zm • AL/3, A2L/3 A X Cross Sectional Area 3D-Duct Design Parametrization

  22. Y Z X X Duct Centerline • Control / Design Variables • Ym, Zm • AL/3, A2L/3 A X Cross Sectional Area 3D-Duct Design Parametrization

  23. Typical 3D-Ducts Generated

  24. Low Fidelity Design Criteria (Constraints) Wall angle < 6° Diffusion angle < 3° 6 * Equivalent Radius < ROC of Centerline Low fidelity analysis for pressure recovery (Objective function) No low fidelity analysis for distortion or swirl For results & discussion http://www.casde.iitb.ac.in/MDO/3d-duct/ 3D-Duct Design Using Low Fidelity Analysis

  25. Low Fidelity Design Criteria (Constraints) Wall angle < 6° Diffusion angle < 3° 6 * Equivalent Radius < ROC of Centreline CFD (Fluent) for pressure recovery & distortion Doyle Knight’s Group @Rutger’s University Optimization of width-depth of bump for minimising distortion. Grid quality required to capture distortion? 3D-Duct Design Using High Fidelity Analysis

  26. 3D-Duct Design Using High Fidelity Analysis X2-MAX ? X2-MIN X1-MAX X1-MIN Domain for search using high fidelity code is large

  27. 3D-Duct Design Using High Fidelity Analysis • Low Fidelity Design Criteria • Wall angle < 6° • Diffusion angle < 3° • 6 * REQ < ROC • Fluent for CFD • RSM / DOE • DACE X2-MAX X2-MIN X1-MAX X1-MIN

  28. 3D-Duct Design Using High Fidelity Analysis • Low Fidelity Design Criteria • Wall angle < 6° • Diffusion angle < 3° • 6 * REQ < ROC • Fluent for CFD • RSM / DOE • DACE X2-MAX X2-MIN X1-MAX X1-MIN http://www.casde.iitb.ac.in/MDO/3d-duct/

  29. Easy integration of analysis modules Support for distributed analysis Optimization environment . . . Salas & Townsend AIAA-98-4740 Commercial Frameworks are available MDO Framework

  30. MDO Framework Issues I cannot find the correct tuning parameters! Why do you want my program? System Designer’s Nightmare! I have a new version of analysis software You have to know my code to be able to execute it! (it’s all in Russian)

  31. Analysis codes should reside with experts. System analysis should execute analysis codes on experts’ computers. Aerodynamics Expert System Analysis Controls Expert Structures Expert MDO Framework Issues

  32. Framework Development @CASDE • Distributed computing (CORBA based) • Database driven • Tools to integrate analysis modules using wrappers • Automatic data exchange between analysis modules

  33. GUI Optimizer Manager OPT1 OPT2 OPT3 Configuration Manager MDO Controller Data Server Database Sequence Logic AM1 AM2 AM3 Execution Manager Name Server Analysis Manager Framework Architecture

  34. f X Optimization Issues • Gradient based optimization • Evaluation of gradients? Finite Difference. • Requirements on convergence more severe • than that required for engineering analysis. • Noisy functions?

  35. Complex Analysis Code in Fortran Manually extract sequence of mathematical operations Manually differentiate mathematical functions - chain rule FORTRAN source code that can evaluate gradients Code the complex derivative evaluator in Fortran User Supplied Gradients

  36. Complex Analysis Code in FORTARN Manually extract sequence of mathematical operations Use symbolic math packages to automate derivative evaluation FORTRAN source code that can evaluate gradients Code the complex derivative evaluator in Fortran User Supplied Gradients

  37. Parse and extract the sequence of mathematical operations Complex Analysis Code in FORTARN Use symbolic math packages to automate derivative evaluation FORTRAN source code that can evaluate gradients Code the complex derivative evaluator in Fortran User Supplied Gradients

  38. Complex Analysis Code in FORTARN Automated Differentiation Package FORTRAN source code that can evaluate gradients Gradients by ADIFOR Euler

  39. Presentation made on behalf of CASDE PM Mujumdar, K Sudhakar Amitay Isaacs, SK Sane, AG Marathe VISIT http://www.casde.iitb.ac.in/ for information on MDO & Other activities

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