MIT | Martin McBrien | Nii Armar | Anas Alfaris16.810 Vehicle Design Summit Team 1Ingress/EgressFabricationAnalysis and OptimizationDesign SystemFabricationAnalysis and OptimizationDesign SystemDesign SystemObjective :Multi-Objective problem Quantifiable Criteria Cost ($)Visibility (sq. m)Egress Ingress (sec)Unquantifiable Criteria Ease of ManufacturabilityAestheticsFabricationAnalysis and OptimizationDesign SystemDesign SystemDesign Variables:Geometry (Number and positions of Joints)Material (Transparency/Opaque)Kinematics (Hinge, Slider..etc)Constrains:Shape of existing Shell (m)Weight (Kg)Cost ($)FabricationAnalysis and OptimizationDesign SystemDesign SystemConceptFabricationAnalysis and OptimizationDesign SystemDesign SystemDesign Solution Tree:FabricationAnalysis and OptimizationDesign SystemDesign SystemFabricationAnalysis and OptimizationDesign SystemDesign SystemFabricationAnalysis and OptimizationDesign SystemDesign SystemFabricationAnalysis and OptimizationDesign SystemDesign SystemFabricationAnalysis and OptimizationDesign SystemDesign SystemFabricationAnalysis and OptimizationDesign SystemDesign SystemFabricationAnalysis and OptimizationDesign SystemDesign SystemFabricationAnalysis and OptimizationDesign SystemAnalysis and OptimizationTest 1 – ‘Hard Opening’• Highest dynamic load when someone opens canopy and pins hit end of rails• Force of 2g * mass of canopy ~ 11 pounds• Restraints of fixed edges roughly equivalent to final design• Stress concentrated around joint• Displacements acceptableFabricationAnalysis and OptimizationDesign SystemAnalysis and OptimizationTest 2 – ‘Driving Pressure Force’• Pressure on canopy while driving 60mph ~550N/m2• Restraints of fixed edges based on magnetic strips• Natural modes at low freq – first mode at 0.5Hz • Canopy displacement ~3mm max at 60mphFabricationAnalysis and OptimizationDesign SystemAnalysis and OptimizationTest 3 – ‘Rail Optimization’• Varied thickness of rail to find optimum size to avoid yield at min mass• Force of 40N side load – someone leaning on canopyThickness FoS(inches)18.90.5 2.70.25 2.0• We tried to use a thicker sandwich material – delaminated• Now using 0.25 inch aluminium, slightly different rail designFabricationAnalysis and OptimizationDesign SystemAnalysis and OptimizationFabricationAnalysis and OptimizationDesign SystemAnalysis and OptimizationFabricationAnalysis and OptimizationDesign SystemFabricationCanopy – Ordered from professional manufacturer in FloridaHandles – Aluminium tube welded onto waterjetted guide railsRails – Aluminium, waterjet, attached by U-ClampAttachment – Adhesive backed magnetic stripFabricationAnalysis and OptimizationDesign SystemFabricationFabricationAnalysis and OptimizationDesign SystemFabricationFabricationAnalysis and OptimizationDesign SystemFabricationFabricationAnalysis and OptimizationDesign SystemFabricationFabricationAnalysis and OptimizationDesign SystemFabricationFabricationAnalysis and OptimizationDesign SystemFabricationFabricationAnalysis and OptimizationDesign SystemFabricationWhat’s Next…?• Handles welded to rails• Attach rail to chassis• Sand shell and canopy• Reinforcing canopy• Attaching canopy to reinforcement• Attaching reinforced canopy to handles• Test mechanism, fix problems!• Stick on magnetic strips so canopy stays shut• Drive AHPV to Solidworks World• Sleep…FabricationAnalysis and OptimizationDesign SystemCost EstimationFabricationAnalysis and OptimizationDesign SystemLessons Learned• Set realistic goals• Better use of FEA for optimization – our rail could have been designed to be lighter• Start manufacturing early, maybe finish on time• Have the right tools• Make the right decisions at the right timeTo be
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