FEMAP Use in Mechanical Analysis for Design and Test of GEOStar
FEMAP Use in Mechanical Analysis for Design and Test of GEOStar Satellites and Subcomponents Andrew Sayles / Thomas McQuigg Orbital ATK Space Systems Group, Mechanical Analysis and Test 4/14/2015 Orbital ATK Proprietary 1 Agenda Introduction Orbital ATK Space Systems Group (SSG) SSG Mechanical Analysis and Test − GEOStar Communication Satellites − Science Satellites − ISS Commercial Resupply Service Primer on Satellite Design Requirements FEMAP for Satellite Modeling Example GEOStar Analysis with FEMAP: 1. Detailed Hold Down Release Mechanism 2. Specialized Mesh Approach in a Corrugated Wave Tube Assembly Model 3. Component Level Test Model Correlation for Test Prediction 4. Structural Test and Strain Prediction for Large Scale Structures Orbital ATK Proprietary 2 A Combination of Two Industry Leaders Merger of Orbital and ATK was completed in February 2015 Orbital ATK Proprietary 3 A New Global Space and Defense Leader Dulles campus is prime facility for Geosynchronous satellite manufacturing Orbital ATK Proprietary 4 Over 800 Space Missions Since 1982* 78 Commercial Satellites 77 Government Satellites 40 Space Payloads 78 Space Launch Vehicles 202 Interceptor & Target Vehicles 346 Sounding Rockets Orbital ATK Proprietary *April 1982-July 2014 5 Premier Aerospace and Defense Customers Orbital ATK Proprietary 6 Extensive Human and Physical Resources Over 13,000 Employees Dedicated to Aerospace and Defense Business 4,300 Engineers and Scientists 7,400 Manufacturing and Operations Specialists 1,400 Management and Administration Personnel Facilities in 17 States With 19.6 Million Sq. Ft. of R&D, Manufacturing, Test, Operations and Office Space 6.1 Million Sq. Ft. Owned 5.4 Million Sq. Ft. Leased 8.1 Million Sq. Ft. U.S. Government Owned Orbital ATK Proprietary 7 Orbital ATK Space Systems Group SSG Mechanical Analysis/Test Working Out of Dulles, VA Focuses on Satellites and Space Systems Areas of Our Business − Commercial Satellites − Science Satellites − Commercial Resupply Mission (Cygnus Service Module) − National Security Satellites Orbital ATK Proprietary 8 GEOStar Satellite Bus: Modular Design Tailored to Customer Needs Emergence of GEOStar3 Product in 2014 5.0 kW Orbital ATK Proprietary 9 Satellite Design: Requirements and Environments 10 Orbital Proprietary and Confidential Sources of Mechanical Design Requirements Structural requirements are derived based on multiple phases of the satellite mission Manufacture and Assembly Transport and Handling Testing Launch and Ascent On-orbit Mission Operations → satisfies business needs of customer Re-entry and landing (if applicable) Antares Launch of Cyngus Vehicle at Wallops Island GEOStar2 Sine Vibration Test Orbital ATK Proprietary 11 Satellite Environments Multiple environments must be considered during analysis: Quasi-static (launch vehicle engine thrust and ascent) Dynamic − Random/Acoustic (LV engine, aerodynamic loading, energy reflection in fairing) − Sine vibration (LV engine) − Shock (separation from LV, deployment of appendages) Thermal (on-orbit loading) Cygnus Vehicle preparing for Acoustic Testing Orbital ATK Proprietary 12 FEMAP in Multi-Phase Satellite Design-Analysis Life Cycle 13 Orbital Proprietary and Confidential Illustrated Overview of the Satellite Structure Design Life Cycle (2) (3) (4) (1) 1. 2. 3. 4. 5. 6. 7. 8. 9. CAD Geometry Design Generation Finite Element Model Generation Modal Analysis Dynamic Analysis for LV Environments Design Load Case Generation Stress Analysis (Dyn/QS/Thermal) Margin of Safety Reporting and Design Iteration Testing – Verification and Validation Completed Design for System Level Testing and Launch (7) (5) Orbital ATK Proprietary (6) (8) (9) 14 Analysis Types and Requirements: Modal Example Deformed Shape – First Bending Free boundary conditions used to assess separation of elastic modes Fixed-base modal analysis characterizes dynamic behavior Evaluates compliance of S/C with LV requirements Component frequency requirements are based on separation from support structure/vehicle modes S/C Primary Mode separation from launch vehicle modes is key for reducing loads generated by coupling between the two vehicles 1 Input (g) AMZ-4A As-Run Z Axis Protoflight Input Notch 0.1 0.01 Frequency (Hz) 10 AMZ-4A Protoflight Input Envelope Ariane 5 MUA Protoflight Longitudinal Input AMZ-4A As-Run Z Axis Protoflight Control channel acc_op1s111s_Z_AMP 100 AMZ-4A Z Axis Protoflight Predicted Notched Input Ariane FCLA Z SRS Envelope Scaled to Protoflight (Q=20) 15 acc_op1s121s_Z_AMP CLA Interface SRS and As-Run Spacecraft Sine Test AMZ-4A As-Run Z Axis Manual Protoflight Input Ariane FCLA Minima Scaled to Protoflight Analysis Types and Requirements: Dynamic Dynamic modal characteristics are evident in various types of dynamic environments Sinusoidal vibration – oscillating load with a specific frequency Random vibration – amplitude and frequency of load are random in nature Acoustic excitation – defined by sound pressure level at a given frequency and somewhat random in nature Shock Input – short duration high frequency acceleration event and rapid attenuation Dynamic loads are typically a source for derivation of design loads Pre-test/flight predictions used to derive loads for stress analysis Sine Vibration Test Prediction – Transfer Function Orbital ATK Proprietary Acoustic Vibration Test Response 16 Analysis Types and Requirements Quasi-Static Quasi-Static Accelerations (Flight) for Launch Vehicle 7 Loads that do not vary in time or magnitude 6 5 4 Point loads (specific application) Body loads (gravitational, LV acceleration) Boundary Displacement (applied or global-local approach) Axial Acceleration (g) 3 P S 2 A 1 S 0 -1 S -2 H -3 -4 S E -5 Loads are governed by specific Launch Vehicle or on-orbit mission requirements -6 Negative a Positive ac -7 -3 -2 -1 0 1 2 3 Lateral Acceleration (g) Launch Vehicle QS Load Factor Envelope Panel Facesheet Failure Index Contour Plot Orbital ATK Proprietary 17 Analysis Types and Requirements Thermoelastic Temperature loads derived from Thermal Group analysis or design requirement Apply temperatures to finite element mesh as nodal loads Multiple loading conditions and combinations often considered to identify worst case condition Conduction is used to derive nodal loads when detailed temperature gradients are not available Distortion analysis is used to find resulting displacements (horn pointing, clearance) Coupled with vendor distortion analysis of reflector surface this feeds into the antenna’s accuracy and performance Strength analysis is used to validate structure design Common problem is material CTE mismatch Spacecraft Temperature Contour and Deformed Shape Shown in On-Orbit Deployed Configuration Orbital ATK Proprietary 18 FEMAP Models of Orbital ATK Satellites 19 Orbital Proprietary and Confidential FEMAP’s Role in Satellite Design Efficiency in model creation and model management is key to producing analyses that support the program’s schedule CAD Orbital ATK Proprietary FEM Launch 20 CAD to FEM - Overview Antenna support structure are comprised of Composite panels Metallic brackets, Mechanical fasteners Bonded clips Other specialized features that support mission concept of operations Orbital ATK Proprietary 21 CAD to FEM – Subcomponent CAD Geometry Preparation Solid objects are decomposed into basic shapes which are then used for meshing Remove filets Orbital ATK Proprietary Create midsurfaces 22 CAD to FEM – Subcomponent CAD Geometry Preparation More complex shapes can be efficiently decomposed using FEMAP’s Meshing Toolbox Orbital ATK Proprietary 23 CAD to FEM – Mesh Connectivity Subcomponents are then integrated using single DOF elements to model interfaces, for which FEMAP Custom Tools are very useful Orbital ATK Proprietary 24 CAD to FEM – On-Spacecraft FEM Integrate model to spacecraft Verify the design loads and complete integrated analysis Orbital ATK Proprietary 25 Modeling Example 1: Reflector Retention and Release Mechanism 26 Orbital Proprietary and Confidential Example 1: Deployment Introduction GEOStar spacecraft travel to orbit in a “stowed” position. Loads induced from launch driven stowed design loads Once on-orbit, solar arrays, reflectors and other structures are deployed Deployment mechanisms must function reliably, since there is no second chance for on-orbit failure Stowed CAD Deployed FEM Orbital ATK Proprietary 27 Example 1: Model Summary Spring Retainer Internal assembly bolted are modeled with preload Contact with friction defined at cup/cone interface as well as others Reflector interface loads are derived from onspacecraft analysis considering acoustic and sine loading from launch vehicle environment Interface loads are applied for detailed stress analysis Cup Cone Mounting Flange ERM Housing Detailed Solid Mesh of Cup Orbital ATK Proprietary 28 Modeling Example 2: Specialized Meshing Approach of Corrugated Waveguide 29 Orbital Proprietary and Confidential Example 2: Corrugated Tube Problem Statement Process forms tube from nominal (straight) into desired shape (bend in corrugations) Forming process changes angle of corrugations Geometry was not available for formed shape Detailed stress analysis was required for formed configuration Generating consistent mesh that accurately represented the formed shape in expanded and compressed corrugations proved difficult Unformed Shape Corrugation Expanded Formed Shape Corrugation Compressed Orbital ATK Proprietary 30 Example 2: Corrugated Tube Meshing Approach Unit rotation was applied to sections of mesh, constrained with RBE2 rigid elements and SPC Custom Tool command “Nodes move by Deform” under Post Processing toolbar Corrugations were compressed and expanded as observed in manufactured shape Isometric View of Unformed Shape Unformed Shape Formed Shape Mesh Fidelity (Actual Deformation) SPC SPC and Rotation Orbital ATK Proprietary 31 Example 2: Corrugated Tube Analysis and Results Dynamic response and stress analysis performed on assembly Modal and random test responses correlated very well with numerical predictions Detailed Stress Analysis Contour - Random Modal Deformed Animation Area of Peak Stress Orbital ATK Proprietary 32 Modeling Example 3: ModelTest Correlation of an Electronics Assembly 33 Orbital Proprietary and Confidential Example 3: Electronics Assembly Electronics assembly required dynamic assessment and stress analysis Mass = 100 lbm Model uses plates, solids, and concentrated mass elements for large chips FEMAP Layering, grouping features enabled efficient model management Solid Model Orbital ATK Proprietary Detailed Finite Element Model 34 Example 3: Electronics Assembly Analytically predicted first major mode nearly identical to test Modal and random test responses correlated very well with numerical predictions Deformed Modal Shape – First Mode Transfer Function Comparison of Prediction and Test Response For Random First Mode Orbital ATK Proprietary 35 Modeling Example 4: GEOStar Primary Structure Static Load Test 36 Orbital Proprietary and Confidential Example 4: GEOStar Primary Structure Static Load Test Introduction Primary structure static load used to verify workmanship and design loads Forces are applied to structure to simulate various loading conditions Finite Element Model Orbital ATK Proprietary Test Plan Article Test 37 Example 4: GEOStar Primary Structure Static Load Test Analysis Results Attach NASTRAN .OP2 files to large spacecraft primary structure FEMAP models Use of global plies is ideal for core shear stress plot generation for a panel and load case envelope when composite panels have multiple layups/ply counts associated with them Import analysis results function is easily used to import .CSV raw analysis results generated using other in-house analytical tools (spreadsheets or MATLAB Scripts) Safety Margin Criteria Plot Honeycomb Shear Stress Contour Plot Orbital ATK Proprietary 38 Example 4: GEOStar Primary Structure Static Load Test Strain Predictions Strain gages placed at areas of interest on the structure Finite Element Model predictions are used as justification to continue with test FEMAP enables efficient composite element processing Test Instrumentation Plan Orbital ATK Proprietary Strain Field and Gage Placement 39 Thanks for your Attention! Any Questions? Orbital ATK Proprietary 40
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