toczynski x-18 front shock mount design review presentation
TRANSCRIPT
Front Shock MountDesign Review
GABE TOCZYNSKI
OverviewRelevant Rules
Requirements
Location on Car
Force Calculations
Design Iterations/FEA
Cost Report/ Comparison to previous design
Relevant RulesT6.1 Suspension
T6.1.1 The car must be equipped with a fully operational suspension system with shock absorbers, front and rear, with usable wheel travel of at least 50.8 mm (2 inches), 25.4 mm (1 inch) jounce and 25.4 mm (1inch) rebound, with driver seated. The judges reserve the right to disqualify cars which do not represent a serious attempt at an operational suspension system or which demonstrate handling inappropriate for an autocross circuit.
RequirementsMaximum Stress Experienced by part to be less than 200 MPA.
Allow for adequate clearance of shock absorber.
Location on CarX-18 Top Level Mock-up with F-260 Shock and Bell Crank
Clearance requirement met
Force Calculations
The loading situation represented is equal to roughly 70% of vehicle and driver mass focused on front corner.
Design Iteration 1FEA Setup
2156 N
Blue line represents simulated connector rod between shock and mount.
Surfaces are fully constrained to represent welds to frame.
Maximum stress is 255 MPA
Design uses 1010 steel in the form of 12 gauge (0.1 inch thickness) sheet metal.
Design Iteration 2
Material Removed to reduce mass. Angle made more obtuse in attempt to lower stress.
NX Model FEA Results
Design change failed. Maximum stress increased to 383 MPA.
Design Iteration 3NX Model
Mass reduced by changing design to 2 plates rather than single bent piece. Elbow angle changed to curve in order to distribute stress more evenly.
FEA Results
Curved part distributes stress more evenly. Maximum stress reduced to 278 MPA.
Design Iteration 4 (Final)NX Model
Mass reduced further by removing material that had low stress in previous iteration. Small amount of material added to some areas to reduce stress.
FEA Results
Maximum stress reduced to 191 MPA. Stress requirement met. Maximum deflection is insignificant at .15 mm.
Type of steelused
Factor ofSafety
1010 1.6
1025 1.9
Cost Report
Vehicle Mass per part Cost per part
F-260 0.20 kg $5.51
X-18 0.07 kg $5.32
Difference 0.13 kg $0.19
Questions?