Realistic Simulation of a Flexible Mechanism using ANSYS Solutions Achuth Rao, Ph.D. Product Line Manager Product Management Group ANSYS Inc.
Solution Brands and Products Structural Fluids Explicit ANSYS/Mechanical Electromagnetics CFX/FLUENT ANSYS/Multiphysics Meshing ANSYS/AUTODYN Optimization ANSYS/EMAG ICEM CFD ANSYS/DesignXplorer
Geometry and CAD integration Benefits Support for all major CAD systems and file formats Bi Directional Associativity Parameter data types supported: Geometry CAD Parameters Material Properties Attributes (Loads; Constraints etc.)
Workflow: Dynamic Drop Test Analysis Benefits Integrated dynamics solver capability Reduces total solution time through meshing; pre processing; solution and post processing Accurate physical representation as compared to rigid multi body solvers Flexibility can be introduced when needed either based on component mode synthesis or full nonlinear analysis CAD associativity allows for easy parametric updated to design CAD: CATIA R17 ANSYS Workbench ANSYS DesignModeler ANSYS Simulation
ANSYS Flexible Multi body Dynamics Benefits Automatic connections setup Implicit structural solution Multi step transient analysis FE based rigid body analysis Nonlinear contact with friction Geometry based loading and processing of dynamics data Rigid to flexible part conversion Component Mode Synthesis (CMS) techniques for model reduction and flexibility
Connectors and FE Representation = Geometry representation FE Mesh Representation Connectors and contact behavior defined on geometry Equivalent FE representation though mass and connectors
Nonlinear Contact Modeling with Friction Contact Mesh Rigid rigid contact model between tire and runway Nonlinear frictional contact with between tires and runway Tire Representation: Tire stiffness and damping modeling using springs and dampers below runway Tire Stiffness and Damping K = 10000 lb/in C = 5 lbf-sec/in
Stiffness and Damping Characteristics 700000 600000 500000 400000 300000 200000 100000 0 0 2 4 6 8 10 12 14 16 18 20 22 Nonlinear Stiffness Curve 1800 Nonlinear Damping Curve 1600 1400 1200 1000 800 600 400 200 0 0 2 4 6 8 10 12 14 16 18 20
Landing Gear without Rotation and Contact Rotation of tires and contact with payment ignored Tire model approximated with a spring damper system 250000 200000 150000 100000 50000 0 0 2 4 6 8 10 12 14 16 18 20 Reaction vs Strut Stroke
Landing Gear with Rotation and Friction Rotation of wheel at approach speed of 150 mph Friction behavior with contact Tire model approximated with a spring damper system 250000 200000 150000 100000 50000 0 0 5 10 15 20 Reaction vs Strut Stroke
Dynamic Drop Test Analysis Reaction vs Strut Stroke
FMBD Solution Strategies & Benefits Traditional Techniques MESH PRE FEA CB MBD POST MESH PRE FE Based Approach FEA POST CB = Craig Bamptom Technique Savings FE based FMBD offers time savings in total solution time as compared to traditional approaches Made possible by an integrated solution environment combined with improvements in solver technology and high performance computing
Workflow: Static Analysis Benefits Easy model reduction and simplification for static analysis CAD associativity allows for easy parametric updated to design Advanced unified meshing tools from ANSYS, ICEM CFD, CFX and FLUENT Integrated design optimization & topological optimization solutions CAD: CATIA R17 ANSYS Workbench ANSYS DesignModeler ANSYS Simulation ANSYS DesignXplorer
Static Analysis: Cylinder & Lug Design Automatic connections and contact definition Geometry and FE based preprocessing and post processing Nonlinear geometry and contact capability Ability to run design changes through parametric model updates
Automatic contact and connections Connections and Contact Definition
Meshing and Pre processing Mesh Metrics
Static Analysis: Dynamic Braking & Turning Turning Loads Displacement Results Equivalent Stress Results
Parameter Manager & Design Optimization Parameter Manager across all applications: Design of experiments Design for six sigma and robust design Input and output parameters from CAD; material properties; boundary conditions and results and derived results variables
Geometry Updates and Design Parameters CATIA model update within ANSYS DesignModeler through parametric design Model updates can be transferred back to CAD system through bidirectional associativity
Automatic Mesh Updates with Design Parameters
Post processing through design iterations Reduced stresses levels Equivalent Stress Displacement Results Equivalent Stress Results
Topological Optimization Upper and Lower Torsion Links Minimization of Structural Compliance
ANSYS System Simulation Capabilities ANSYS Workbench provides an integrated solution environment for CAD geometry, meshing, CFD, implicit/explicit structural dynamics and optimization Landing Gear Acoustics Simulation using FLUENT Capabilities for system simulation of aircraft landing gear Structural dynamics simulation of landing gear Thermal analysis of landing gear brake assembly Brake squeal analysis of landing gear brake dynamics CFD analysis for landing gear noise simulation