Multiaxial low cycle fatigue behavior and life prediction of CP‐Ti under non‐proportional stress‐controlled mode

Abstract

Multiaxial low cycle fatigue tests under non‐proportional stress (NPSS) controlled mode were performed on commercial pure titanium (CP‐Ti). Strain responses of axial and torsional channels under highly applied stress amplitudes show an initial hardening phenomenon. Non‐proportional hardening coefficient of CP‐Ti is independent of the controlled mode. The critical plane of CP‐Ti under NPSS controlled mode is aligned with the maximum principal stress plane proved by optical microscopy observation. Optimized FSM model and KBM‐PM model with mean axial and torsional strain are established. These models are further integrated into equations related to multiaxial stress ratio with high accuracy of life prediction for CP‐Ti under NPSS controlled mode.

Fatigue life prediction of notched components under size effect based on strain energy density gradient

“…In this regard, Ronchei et al 24 also presented a new criterion for engineering components, which is applicable to different metals with two different non‐proportional sensitivities. Ma et al 25 used commercial pure titanium as the research object to perform fatigue experiment under stress‐controlled conditions, and the results suggested that the additional strengthening of the material and the control model are independent.…”