(problems with) optimising brake disc design by simulation (problems with) optimising brake disc...
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(Problems with)(Problems with)Optimising Brake Disc Design Optimising Brake Disc Design
by Simulationby Simulation
(Problems with)(Problems with)Optimising Brake Disc Design Optimising Brake Disc Design
by Simulationby SimulationOptimising Brake Disc Design Optimising Brake Disc Design
by Simulationby SimulationOptimising Brake Disc Design Optimising Brake Disc Design
by Simulationby Simulation
Bill Young
Senior Consultant, Design and Simulation
Optimising Brake Disc Design Optimising Brake Disc Design by Simulationby Simulation
Optimising Brake Disc Design Optimising Brake Disc Design by Simulationby Simulation
OutlineOutlineOutlineOutline
“Design and Simulation”
Simulation Tools
Optimisation Tools
Opportunities for Optimisation
Simulation ToolsSimulation ToolsSimulation ToolsSimulation Tools
“Horses for courses”
Range of analysis types
Durability
Impact and Safety
Range of software
MSC.Nastran
LS-Dyna (explicit and implicit options)
Brake Disc AnalysisBrake Disc AnalysisBrake Disc AnalysisBrake Disc Analysis
Mechanical, thermal stress, distortion
Optimisation ToolsOptimisation ToolsOptimisation ToolsOptimisation Tools
“Heuristic approach”
Structural Optimisation – MSC.Nastran SOL 200Element properties are design variables; nominated objective function is minimised/maximised
Shape (Topology) Optimisation – Optistruct (HyperWorks)Elements are potential voids; material is distributed most efficiently to address loads
Either process needs feeding with appropriate data
Optimisation InputsOptimisation InputsOptimisation InputsOptimisation Inputs
ObjectiveLightest (cheapest) design allowing…
Variables(Real) design parameters to be changed within design envelope, keeping within…
ConstraintsLimits to structural response
Hill-climbing analogy
Case Study: Case Study: MG TF Suspension ConceptMG TF Suspension Concept
Case Study: Case Study: MG TF Suspension ConceptMG TF Suspension Concept
Re-engineer the system to give improved ride and handling
Enhance the vehicle’s “sporty” feel
Prolong product life
Lower manufacturing costs
MG’s Trailing ArmMG’s Trailing ArmConceptConcept
MG’s Trailing ArmMG’s Trailing ArmConceptConcept
Tubular steel fabrication
High strength
Low cost manufacturing
Final DesignFinal DesignFinal DesignFinal Design
Spheroidal Graphite Cast Iron 10% lighter than standard cast ironOver twice as strong
From CAD to parts in 5 days
Optimised for weight and performanceUsing analysis at the point of design
Low cost / low investment Half the price of the fabricated option
Trailing Arm Concept DesignTrailing Arm Concept DesignTrailing Arm Concept DesignTrailing Arm Concept Design
Follow-up exercise (Optistruct)
Define packaging spaceBush mountingTetrahedral modelDesign & nondesign zones
Trailing Arm Concept DesignTrailing Arm Concept DesignTrailing Arm Concept DesignTrailing Arm Concept Design
Single load case effect (braking)
Reaction at bushes, general stress determines design
Trailing Arm Concept DesignTrailing Arm Concept DesignTrailing Arm Concept DesignTrailing Arm Concept Design
Multiple load cases
Residual shape: load paths
Most effective use of material
But… manufacturing constraints dictate further changes (eg stiffness during machining)
Opportunities for OptimisationOpportunities for OptimisationOpportunities for OptimisationOpportunities for Optimisation
“There are no problems, only opportunities”
Tools and computing power exist
Geometry, (material properties) exist
“Opportunity” lies in defining constraints (combination of loads and limits to responses)
Dealing With OpportunitiesDealing With OpportunitiesDealing With OpportunitiesDealing With Opportunities
(Not enough directly relevant data)
Conservative assumptions
Averaged/Extrapolated data
Data from “similar” design
Relative, not absolute
Simplify!
Solving Problems - Seizing Solving Problems - Seizing Opportunities for OptimisationOpportunities for Optimisation
Solving Problems - Seizing Solving Problems - Seizing Opportunities for OptimisationOpportunities for Optimisation
Address Definition of Loads and Restraints (Supports)
Thermal – friction-inducedCFD input to heat transfer/temperature prediction problem?
Mechanical – manufactureCasting/forging simulation for residual stresses?
Mechanical – assemblyPre-load simulation, tolerance sensitivities?
Mechanical – brakingLocal load distribution dependant on other components? Use more sophisticated (assembly) models? Integrate (ADAMS)