TY  - JOUR
AB  - Purpose Crack tip stresses are used to relate the ability of structures to perform under the influence of cracks and defects. One of the methods to determine three-dimensional crack tip stresses is through the J-Tzmethod. The J-Tzmethod has been used extensively to characterize the stresses of cracked geometries that demonstrate positive T-stress but limited in characterizing negative T-stresses. The purpose of this paper is to apply the J-Tzmethod to characterize a three-dimensional crack tip stress field in a changing crack length from positive to negative T-stress geometries.Design/methodology/approach Elastic-plastic crack border fields of deep and shallow cracks in tension and bending loads were investigated through a series of three-dimensional finite element (FE) and analytical J-Tzsolutions for a range of crack lengths ranging from 0.1⩽a/W⩽0.5 for two thickness extremes of B/(W − a)=1 and 0.05.Findings Both the FE and the J-Tzapproaches showed that the combined in-plane and the out-of-plane constraint loss were differently affected by the T-stress and the out-of-plane size effects when the crack length changed from deep to shallow cracks. The conditions of the J-Tzdominance on the three-dimensional crack front tip were shown to be limited to positive T-stress geometries, and the J-Tz-Q2D approach can extend the crack border dominance of the three-dimensional deep and shallow bend models along the crack front tip until perturbed by an elastic-plastic corner field.Practical implications The paper reports the limitation of the J-Tzapproach, which is used to calculate the state of three-dimensional crack tip stresses in power law hardening materials. The results from this paper suggest that the characterization of the three-dimensional crack tip stress in power law hardening materials is still an open issue and requires other suitable solutions to solve the problem.Originality/value This paper demonstrates a thorough analysis of a three-dimensional elastic-plastic crack tip fields for geometries that are initially either fully constrained (positive T-stress) or unconstrained (negative T-stress) crack tip fields but, subsequently, the T-stress sign changes due to crack length reduction and specimen thickness increase. The J-Tzstress-based method has been tested and its dominance over the crack tip field is shown to be affected by the combined in-plane and the out-of-plane constraints and the corner field effects.
VL  - 10
IS  - 5
SN  - 1757-9864
DO  - 10.1108/IJSI-04-2019-0031
UR  - https://doi.org/10.1108/IJSI-04-2019-0031
AU  - Yusof Feizal
AU  - Leong Karh Heng
PY  - 2019
Y1  - 2019/01/01
TI  - Elastic-plastic J-Tzdominance in bending and tension loadings
T2  - International Journal of Structural Integrity
PB  - Emerald Publishing Limited
SP  - 644
EP  - 659
Y2  - 2024/04/25
ER  -