Martinovic 3D Structures Tools

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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 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

Tool Outline: 

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) FEMCI Workshop 2005 Poster Session

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

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

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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 FEMCI Workshop 2005 Poster Session

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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 FEMCI Workshop 2005 Poster Session

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

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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 FEMCI Workshop 2005 Poster Session

Proof of Concept: WingSizer: 

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 FEMCI Workshop 2005 Poster Session If only wing needs to be studied, user may use a standalone program: Wingsizer ….

WingSizer Analysis: 

WingSizer Analysis Mesh FEA Size FEMCI Workshop 2005 Poster Session

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

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

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

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

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

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Scaling of unit Loads And Loads and Balancing 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) FxORB FzORB FxSRB FzSRB Inertia Aero FEMCI Workshop 2005 Poster Session

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

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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

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

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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 FEMCI Workshop 2005 Poster Session

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

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