Experimental and numerical investigation of ratcheting behavior of SS316L seamless straight pipe under cyclic internal pressure and in-plane cyclic bending

Abstract

In this paper, the ratcheting behavior of SS316L seamless straight pipes under cyclic internal pressure and in-plane cyclic bending is investigated experimentally and numerically. In order to applying the simultaneous cyclic bending and cyclic internal pressure, a special fixture was designed that can be mounted on the gripers of fatigue machine and so ability to apply cyclic pressure to inside pipe specimen and apply in-plane cyclic bending on pipe specimen simultaneously. According to experimental fatigue data, increasing the cyclic bending load and cyclic pressure, increases the accumulation of ratcheting strain in hoop and axial directions. So axial ratcheting strain creates due to cyclic bending and hoop ratcheting strain creates due to cyclic pressure inside pipe specimen. Finally, the finite element analysis was performed by ABAQUS software base on the nonlinear kinematic/isotropic hardening model and the experimental fatigue data were compared with the numerical results and it was found that the numerical results are in good agreement with experimental data.