Novel fatigue life prediction approach combined with rain‐flow cycle counting process for random multiaxial non‐proportional loading
Lei He, Le Xu, Takamoto Itoh
Abstract
Abstract This study extends an existing fatigue life prediction approach for constant multiaxial non‐proportional loading, which is based on a material constant and non‐proportional factor of the loading path, to random amplitude loading waveforms and combines it with the rain‐flow cycle counting method. To validate the accuracy of the extended fatigue life prediction approach, fatigue tests under constant and random uniaxial and non‐proportional loading conditions were conducted. Moreover, fatigue limit reduction under constant non‐proportional loading was investigated through crack and dislocation structure observations. Then, fatigue lives under random multiaxial non‐proportional loading conditions were evaluated using the extended approach. According to the results, almost all evaluated failure data were distributed within two‐factor band lines, indicating that the extended approach could accurately evaluate the fatigue life of the study material.