Testing and assessment of fatigue life prediction models for Indian PHWRs piping material under multi-axial load cycling

摘要

In the present paper, experimental and analytical fatigue studies on primary piping material of Indian PHWRs, have been carried out under multi-axial loading with an aim to assess the adequacy of currently used fatigue life models based on ASME B&PV Sec-Ⅲ procedure and plastic strain energy density. The experiments were conducted under axial, torsion and combined axial-torsion loading with different loading waveforms, phase angle and strain ratio (shear to axial). The tests under varying principal directions loading resulted in shorter fatigue lives. The orientations of crack initiation plane were measured and found dependent on the loading parameters which supports the idea of critical plane based fatigue models.