Damage Accumulation in a Novel High-Throughput Technique to Characterize High Cycle Fatigue

Abstract

Abstract A multiple-insert carrier plate assembly has been developed to increase the throughput of vibration-based fatigue testing. Typically, in vibration-based fatigue testing, a cantilevered rectangular plate is excited in a high-frequency resonant mode until failure. In this manner, an S-N curve for bending fatigue can be constructed. The concept behind vibration-based fatigue testing has been improved by employing a U-shaped carrier plate and fastening multiple smaller specimens into the channel of the carrier plate, such that fatigue tests can be conducted in tandem. However, because of the presence of a variable stress field over the surface of the assembly, the strain in the specimens is unequal. To account for this unequal strain distribution, a framework is provided for estimating how damage accumulates within each specimen. Using this framework, the efficiency gained by adopting a multi-insert approach is evaluated. By optimizing the strategy with which specimens are replaced as they fail, a throughput 5.49 times greater than sequential testing is shown to be feasible.