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Baskar RajagopalanProduct Manager, MSC.Software
Realistic Simulation of aRealistic Simulation of aFlexible Mechanism using MSC.SoftwareFlexible Mechanism using MSC.Software’’s s
SimEnterprise SolutionsSimEnterprise Solutions
MSC SimEnterprise Solution SetMSC SimEnterprise Solution Set
Model development• SimXpert Structures, Motion Workspaces• Expert/method analyst focus• Advanced MD environment• Best practice author/capture for re-use• Simulation process automation
MD Nastran / SimXpert Motion Solver Technology• Common, Multi Discipline embedded solver foundation• Cross platform all-in-one simulation engine• Enterprise computing access via gateway
MD Workspaces
High Level Solution ProcessHigh Level Solution Process
MD Nastran / SimXpert Motion• Drop test Simulation• Flexible Body Motion• Structures Optimization
CATIAData Simulation
Model
Results
Landing Gear Simulation ProcessLanding Gear Simulation Process
• Process Details– Attach to initial geometry in CAD models
– Develop a multi-body dynamics (MBD) model of the LG assembly• Include flex bodies where appropriate• Inner & outer cylinder only
– Use MBD model to simulate rigid and flexible landing conditions
– Extract time domain loading conditions from the flexible landing simulation
– Develop an FE model of the LG assembly• Re-use flex parts & joints from MBD model
– Use FE model to simulate quasi-static applied loads
– Apply the quasi-static applied loads and simulation loads to topological optimization of the LG assembly components
– Update geometry of the LG components based on simulation(s)
Landing Simulation ResultsLanding Simulation Results
AVI
Landing Simulation ResultsLanding Simulation Results
Load-Stroke Response
Vertical tire reaction
Damping coefficientDamping coefficient
Damping Coefficient Vs Stroke
• Initial damping curve resulted in loads outside design envelope• SimEnterprise supports simulation of active damping and shock strut metering pin
design– For this study the revised curve was obtained through simple iterative studies
S
CD
Landing & Taxiing Simulation ProcessLanding & Taxiing Simulation Process
• Process Details– Utilize CATIA geometry– Model lugs so they can be easily
modified without affecting the cylinder meshes
– Mesh solids– Define properties– Define contacts at joints and
“glue” lugs back on– Conduct static analysis based on
loads from dynamic landing simulation and known braking/turning loads
– Review results
Braking, Turning and Landing Braking, Turning and Landing -- Simulation ResultsSimulation Results
Braking Turning Landing loads
Design OptimizationDesign Optimization
• Process Details– Define ‘design’ region – for this
demonstration the upper and lower links were considered ‘designable’
– Conduct topology optimization (MD Solver technology) to determine distribution of material in links
– Review results and output geometry from topology optimization back to CAD system
– Define new geometry in CAD system that allows the definition of design variables for shape optimization
– Conduct shape optimization for design variables
Link OptimizationLink Optimization
Topology design regions Optimized topology
Optimized topology to CADOptimized topology to CAD
Optimized topology
Smoothed….
Imported to CAD
Refined CATIA Geometry
Lug Design EvolutionLug Design Evolution• Engineering judgment leads to addition of fillet radii• Shape optimization quantifies optimal radii dimension
Summary / Closing CommentsSummary / Closing Comments
• Flexible landing gear simulation process successfully completed
• Leveraged key strengths of SimEnterprise solution set
– Single simulation environment– Model re-use across disciplines –
common data model– Integrated MD solver– Native access to CAD geometry – no
translation• Additional capabilities not
demonstrated– Control system integration - active
damping– Fluid/gas simulation of shock strut with
metering pin – Feature optimization based on mesh
morphing– Integration of flight dynamics
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