CD-04 Campbell Downs
Project 04 · CAD + Analysis

Pull-Up Bar Fatigue Optimization

Static and fatigue analysis of a cyclically loaded consumer fitness component.

Fatigue Material choice Cost focus
Original von Mises stress plot of the pull-up bar
Original static stress under a 250 lb user load with both bar ends fixed.

Evaluated a pull-up bar under a 250 lb user load, then modified geometry and material selection to reduce cost and material usage while preserving long-term durability.

250 lbUser load
10 yrUse target
1MOriginal life cycles

Original study

1112 N downward load, both bar ends fixed, zero-based fatigue loading, 208,572 cycle design target.

Original pull-up bar CAD model
Original model.
Original static stress plot
Original static stress.
Original fatigue life plot
Original fatigue life plot.

Cost and weight-conscious redesign

The original design was overbuilt, leaving room for material and cost reduction.

Improved pull-up bar geometry
Improved geometry.
Improved static stress plot
Improved static stress.
Improved fatigue life plot
Improved fatigue life.

284,160

Minimum fatigue cycles after redesign. Above 10-year target.

Optimization choices

Increased inner diameter, reduced handle outer diameter, and changed material from AISI 1020 steel to A36 steel to improve manufacturability and reduce cost.