FSAE Spool Statics Suite
MATLAB statics suite for LR21 drivetrain — chain tension, bearing reactions, Von Mises checks, and diff-mount bolt torque specs.
项目方向
机械设计
Key Features
Five-script statics pipeline
Chain back-tension per tooth
Bolt clamping and install torque
Scope of work
Deliver a repeatable statics toolchain for Lehigh Racing LR21 rear drivetrain decisions before FEA became the default path:
- Resolve chain tension from engine torque and sprocket geometry
- Split bearing reactions across asymmetric bracket standoffs
- Build shear and moment diagrams along the spool shaft
- Model roller-chain back-tension decay around sprocket wrap
- Check Von Mises stress and static safety factor at critical sections
- Output friction-based bolt clamping and installation torque for diff mounts
Out of scope: dynamic lap simulation, tire model coupling, full bracket FEA (handled in separate workflows).
Timeline
| Phase | Window | Milestone |
|---|---|---|
| Problem framing | Fall 2020 | Identify spool/bracket weak-link questions from prior-season reports |
| Force scripts V1 | Winter 2020–21 | LR21_Drivetrain_Forces_V1.m — tension, reactions, V/M diagrams |
| Bracket extension | Spring 2021 | LR21_Drivetrain_Forces_V2.m — 2D link geometry from CAD |
| Chain tooth model | Spring 2021 | LR21_Drivetrain_Backtension_V1.m |
| Stress + fasteners | Apr 2021 | Stress check and LR21_Drivetrain_TorqueSpecs.m |
| Handoff | Apr 2021 | Repo published; used for LR21 hardware sign-off |
Stack & BOM (software)
| Item | Role |
|---|---|
| MATLAB R2020b+ | Script runtime and plotting |
| LR21 CAD exports | Link lengths, bracket hard points (mm) |
| X49/X50 drivetrain notes | Inherited torque and layout assumptions |
GitHub spool-static-calcs | Versioned script suite (5 .m files) |
Deliverables
- Documented MATLAB scripts with LR21 naming convention
- Bearing reaction and spool shear/moment outputs for design reviews
- Per-tooth chain force plot for sprocket engagement review
- Von Mises stress summary with static safety factor
- Bolt torque specification worksheet for diff mounts
- GUI linkage editor (deferred — repo README still marks unfinished)
Outcomes
- Gave the team numbers tied to CAD geometry instead of symmetric beam approximations
- Surfaced left/right bearing load imbalance that easy FBD sketches missed
- Supported bracket and bolt decisions on LR21 without waiting on full FEA turnaround
Constraints & assumptions
- Static analysis only — no transient engine ripple or wheel lift modeled in this suite
- Material properties and section moduli entered manually per review
- Scripts assume validated CAD link lengths; garbage-in breaks reaction magnitudes fast
Completed on: 2021年4月15日