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FEMCI Workshop 2005 Poster Session

FEMCI Workshop 2005 Poster Session. LaRC/Exploration Concepts Branch 3D Finite Element Based Structures Tools May 4-5, 2005 Goddard Space Flight Center Zoran N. Martinovic NASA/LaRC Jeffrey A. Cerro NASA/LaRC Lloyd B. Eldred / Swales Aerospace Philip Su / Raytheon Corp.

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FEMCI Workshop 2005 Poster Session

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  1. FEMCI Workshop 2005 Poster Session LaRC/Exploration Concepts Branch3D Finite Element Based Structures Tools May 4-5, 2005 Goddard Space Flight Center Zoran N. Martinovic NASA/LaRC Jeffrey A. Cerro NASA/LaRC Lloyd B. Eldred / Swales Aerospace Philip Su / Raytheon Corp.

  2. FEMCI Workshop 2005 Poster Session Objective: • To quickly create coarse vehicle 3D models which are subject to typical structural design loads • To estimate Level 2 primary structure weights during conceptual design phase - Level 0 weight estimates are based on historical data - Level 1 weight estimates are line model subject to shear, moment and axial force estimates - Level 2 coarse FEM structural weight estimates - Level 3 detailed FEM structural weight estimates • To do structural trade studies

  3. FEMCI Workshop 2005 Poster Session Tool Outline Semi-automated iterative procedure for structural weight estimation and trade studies of new vehicle design concepts • JAVA - Object Oriented process control language (original process was wrapped in Phoenix Integration/Model Center) • UGS / I-DEAS - CAD/CAE • Collier Research / HyperSizer - Structural component sizing • LOFT - Swales code to quickly create FEMs with property assignment regions defined • EXCEL Solver - utility used for balancing of flight loads • HSLOAD - Swales code to automate the HyperSizer design process • Multidisciplinary input from CONSIZ (Subsystem weights), POST (Trajectory), CBAERO (Aero)

  4. FEMCI Workshop 2005 Poster Session Process Outline POST Flight Profile with Accelerations & CBAERO generated Aero-forces Vehicle Geometry and Weights CONSIZ LOFT Generated Mesh INPUT Geometry INPUT Gs & Fs INPUT Lump Mass INPUT FE Mesh Loaded I-DEASFE Model I-DEASFE Model Load Balancing EXCEL Solver [M], [K] Finite elements organized in groups/Panels Running loads [Nx, Ny, Nxy ……] I T E R A T I O N L O O P New [K] & Struct. [M] HSLoad / HYPERSIZER Model Panel sizing in HYPERSIZER Assign: • Panel/beam Concept • Material • Limits on design variables • Failure Criteria Zoran N. Martinovic/VAB/NASA LaRC/ June 2004

  5. FEMCI Workshop 2005 Poster Session Geometry, packaging and sub-system weights received …..

  6. FEMCI Workshop 2005 Poster Session LOFT Automatic Finite Element Mesh Generation For Aerospace Vehicles • Use supplied Geometric Dimensions • Generate Panels, Frames, Beams/Bars for a full or partial vehicle • Mark each element with User Specified component names and coordinates • Attach to commercial codes for FEA and sizing • Post process sizing results

  7. FEMCI Workshop 2005 Poster Session LOFT Extrudes between arbitrary cross sections Builds objects using panels, beams and bars Merges objects to form a single FE model Portable C code with Text Input # ISAT Reference Mach 3.4 TSTO Vehicle # Our nose object dome BST Nose curve1 sc c1_xscale 15.589 c1_yscale 15.589 length -36 taper para nodes_circ 21 nodes_axial 20 droop line zdroop 8

  8. FEMCI Workshop 2005 Poster Session Desired forms are programmed … Example of LOFT input file

  9. FEMCI Workshop 2005 Poster Session LOX FW Dome LOX Barrel LOX Ring Frame LOX Aft Dome LOX Longeron Property Assignments Create Physical and Material Property Names to mark Engineering components Allows easy application of sizing parameters to different Vehicle sections and easy post processing Meaningful names allow different construction approaches across the vehicle

  10. FEMCI Workshop 2005 Poster Session Proof of Concept: WingSizer • High fidelity tool to estimate wing structural weights • Generates detailed FE mesh • Calls FEA solver • Calls and controls sizing program • Postprocesses results If only wing needs to be studied, user may use a standalone program: Wingsizer ….

  11. FEMCI Workshop 2005 Poster Session WingSizer Analysis Mesh FEA Size

  12. FEMCI Workshop 2005 Poster Session Process Highlights Geometry Model LOFT FEM Mesh

  13. FEMCI Workshop 2005 Poster Session Nose cone LOFT generated model is imported to UGS/I-DEAS for static analysis … Nose gear bulkhead Fin Nose skirt Wing center section LOX tank Inter-tank Wing Aft transition skirt Forward LH tank Model consists of shells (panels) and … Fwd. transition skirt Aft LH tank Bay fwd. bulkhead Payload bay Thrust structure Bay aft bulkhead Thrust structure bulkhead Zoran N. Martinovic/VAB/NASA LaRC/ June 2004

  14. FEMCI Workshop 2005 Poster Session Nose Skirt … beams (frames and longerones) LOX Tank Bay Inter tank FWD LH Tank Transition Skirts Longerones around circumference AFT LH tank Thrust

  15. FEMCI Workshop 2005 Poster Session Sub-system masses are mapped and lumped to FEM … CONSIZ output file Mapping template file Mapping file into FEM XE XB Component mapping x fofx mapping

  16. FEMCI Workshop 2005 Poster Session Individual Unit Loads are applied and model analyzed for each of them … 1 psi Unit load … propellant loads are applied for each flight point and model analyzed for each of them …

  17. FEMCI Workshop 2005 Poster Session Objective function: Pitch moment = 0 1 psi Unit load Scaling factors I-DEAS/EXCEL/Text/JAVA Constraints on axial and normal force, and other flight constraints Sum of balanced forces and moment Scaling of unit Loads And Loads and Balancing Aero Inertia FzORB FxORB FzSRB FxSRB • Unit load sets are scaled, combined and balanced to create actual design loads. • Inputs are vehicle accelerations from design conditions (POST) • and aero loads mapped from CBAERO (or user input fields in FEA)

  18. FEMCI Workshop 2005 Poster Session Propellant Tanks with Head pressure and Ullage pressure Booster Wing Lift and Flap Lift Orbiter ½ Wing Drag Booster ½ Nose Drag Orbiter ½ Fin Drag Balanced flight loads are applied to the FEM in UGS / I-DEAS and static analysis is done … Booster ½ Wing Drag Booster ½ Fin Drag az Orbiter ½ Nose Drag ax T W Booster Body Lift

  19. FEMCI Workshop 2005 Poster Session Model, subdivided into panels and beams, is imported to Collier Research / HyperSizer … … with internal running loads … … and sized for minimum weight with different structural concepts and materials

  20. FEMCI Workshop 2005 Poster Session Model with new structural mass and stiffness is imported to UGS /I-DEAS and process iterates until converges.

  21. FEMCI Workshop 2005 Poster Session Summary Complex vehicle designs multiple body ground/ascent/entry loads Integral panels Variety of panel and beam designs metallic composite Frame Stiffened Semi-monocoque shell

  22. FEMCI Workshop 2005 Poster Session Reference configurations in development Atlas 5 Heavy Space Shuttle Shuttle Derived Lifting Body RLV – TSTO and OSP RLV - SSTO

  23. FEMCI Workshop 2005 Poster Session Other applications under considerations Launch vehicle payload fairings Capsules

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