Crimson Racing Wiki

Actuation Tab (Front)

Subteam: SuspensionSubsystem: ArmsAssembly: Front A-ArmsCars: CR22

Purpose

CR22 tab on the front upper A-arm that the pullrod attaches to.

Function

Welded on CR22; machined into the bearing holder from CR26I, which removed the welding jig setup and most of the build time.

Design Process

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.

Manufacturing Process

Waterjet or laser cut, then TIG welded to the frame in the welding jigs.

Full Material List

Steel.

Reoccuring issues

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.

Still to document

Nothing in CrimsonStorage covers these yet.