Prediction of Shape Change for Fatigue Crack in a Round Bar Using Three-Parameter Growth Circles

Abstract

The conventional method for predicting the shape change of a surface crack in a round bar simply utilizes the Paris-Erdogan law with the least squares method using a certain shape assumption with excessive constraints. In this paper, a three-parameter model for a round bar subjected to tension is developed with fewer shape assumption restraints by employing a fatigue crack growth circles method. The equivalent stress intensity factor Δ K e based on both stress intensity factors along the current and new crack front is used to reduce the total number of increments. The results show that the proposed method has a good convergence speed and accurate prediction of crack shapes. The present method is validated by comparing the solution with other simulation solutions and experimental data.

Experimental and Numerical Investigation of Crack Propagation in Spherical Porous Cylindrical Specimen under Mixed Mode Loading

“…To investigate the SIF under mixed mode I/III loading conditions, some studies were performed experimentally and numerically. Yang et al studied prediction of shape change for fatigue crack and validated by comparing the solution with other simulation solutions and experimental data [2]. Lin et al examined the fatigue growth of surface, internal and multiple cracks in both notched and unnotched round bars subjected to remote tension or bending loads [3].Van et al investigated the problem of crack propagation behaviour under tensile or bending fatigue loads.…”