House the outboard spherical bearing of the rear lower A-arm.
A machined part providing the interface between the component and the structure, positioning it accurately enough that the designed geometry is what the car actually has.
No part-specific design process is documented. The Arms subsystem design process applies: 1. Take the geometry points from kinematics and the wheel loads from the load cases: CR26I front outside cornering 648.691 lbf vertical and 786.094 lbf lateral, braking 585.523 lbf vertical and 763.26 lbf longitudinal, combined 768.095 / 785.550 / 444.124 lbf. 2. Resolve loads into each member with Altair HyperWorks MotionView. 3. Size the tubes in the calculator against buckling and yield. CR26I front upper 0.375 in OD / 0.305 in ID at minimum FoS 1.946; rear upper same tube at 2.581; front lower 0.625 / 0.527 at 2.49; rear lower 0.5 / 0.402 at 2.62. 4. Analyse the spherical bearing holder with two FEA setups so the boundary conditions are cross-checked: bearing fixed with loads at the pullrod bolt and arms, then arms and pushrod bolt fixed with a remote load at bearing centre. Validate the tab stress against a hand calculation for a hole centred in a wall (calculated 18.95 ksi against 22 ksi FEA). 5. Weld in the jigging assembly, then measure the finished arm.
Rear lower spherical bearing holder FEA: AISI 4130, peak stress 21.74 ksi, FoS 3.069.
2D design for waterjet. Explicitly outside the CR26I scope to redesign.
AISI 4130 steel. From the cost report drawings and CAD: From the cost report drawings: AISI 4130 Alloy Steel (CR25_SUS_RearLowerSBH).
None recorded. This part has no entry in Knowledge_Transfer/Issue Logging/Fault Vault.xlsx, in either Issue Log.xlsx, in CR22/Issue Tracking/Shakedown 7-15-23.xlsx, or in any design review issue list found in CrimsonStorage or Box.
Dimensions called out on the cost report drawings. These are the figures printed on the drawing, not a labelled specification; open the drawing itself for what each one refers to. CR25_SUS_RearLowerSBH (as drawn): 11.52, R1.15, 59.80, 5.98, 6.35, 0.64 CR26I_RearLowerBearingHolder (mm): TRUE R15.9, TRUE R11.5, 59.8, 63.4, 6.4 Source: Cost report drawings: CR25/Suspension/Management-Comp/Cost Report/Drawings/Sus Shocks - Rear A-Arms/CR25_SUS_RearLowerSBH.pdf; CR26i/Suspension/Competition/Cost Report Drawings/Suspension and Shocks/Rear A-Arms/CR26I_RearLowerBearingHolder.pdf Quantity per car, as costed: 2
Nothing in CrimsonStorage covers these yet.