Case Study 3 – Integrated Engineering Approach

Component Fatigue Analysis and Redesign

A nickel super-alloy axle was exposed to multiple load scenarios. These loadings can include but are not limited to torsion, bending and direct compression axial loading.

The part was experiencing premature in service failure. After investigation, the fracture surface of failed components identified fatigue as failure mode.

The approach outlined in this case study was used as a complete engineering approach to analyse and replicate the failure and then design and verify new solutions to eradicate the failure.

Stage 1 – Failed component forensic review to establish failure mechanisms / modes / patterns.

Stage 2 – A first principles approach was applied. Classical stress analysis and FE stress concentration study carried out. Analysis demonstrated potential failure under the operating loading conditions.

Stage 3 – Fatigue model created for life prediction. Full scale physical combined load testing executed. Failure occurred in line with the FE predications.

Stage 4 – Through refinement of material grain structure and the reduction (and relocation) of critical stress concentrations, a new component was designed with infinite fatigue life under the same operating conditions.