The Effects of Shot Peening Highly Loaded Compression Springs

The compression spring in this test study is typical of one used in a demanding off-road vehicle suspension. The cyclic loads applied during fatigue tests were severe enough to cause failure in approximately 11,000 cycles without shot peening. The objectives of this study were the following: (1) Design a compression spring similar to those used in the off-road recreational industry. (2) Design & manufacture a fatigue test stand that could withstand high loads for months of testing. (3) Generate a matrix of shot peening treatments to produce different amounts of residual compressive stress. (4) Measure the shot peening residual compressive stress via X-Ray Diffraction (XRD). (5) Correlate the residual stress to fatigue life performance. (6) Evaluate the effects of a post shot peening bake cycle on fatigue performance.