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Determination of Crack Propagation Direction Using IP Theory

Ashish K G Saran1, V G Ukadgaonker2, and
1.Department of Mechanical Engineering, Quantum School of Technology, Roorkee.
2.Department of Mechanical Engineering, Indian Institute of Technology, Bombay.

Abstract—Classical design assumes homogeneous, defect free material. But all materials inherently contain some defects such as a hole, a notch, a slot, slag inclusions, cracks in weldment or heat affected zones due to uneven cooling, presence of foreign particles etc. So the assumption of continuum is not valid and the effect of these discontinuities (Parker A P, 1981) is to be considered. A crack may initiate and grow during the use of the component which after reaching a critical crack length leads to the failure of the component. Thus the problem of crack initiation and extension in the elasto-plastic region is important. Several theories have been proposed to describe the manner in which a crack will propagate in mixed mode condition such as Griffith’s theory, Irwin’s theory, MTS criterion, G-criterion, S-criterion, T-criterion, R-criterion etc. Adding to these a new theory of crack initiation, called Ip theory (Theocaris and Andriopoulos, 1982), was proposed by Ukadgaonker and Awasare. In this report an attempt has been made for the stress analysis during crack extension initiation using ‘Ip theory of crack initiation’ with basic objective of determination of angular location of crack extension initiation.

Index Terms—Crack initiation, propagation, fracture mechanics, Ip theory, failure of component

Cite:Ashish K G Saran and V G Ukadgaonker, "Determination of Crack Propagation Direction Using IP Theory," International Journal of Mechanical Engineering and Robotics Research, Special Issue, Vol. 1, No. 1, pp. 219-226, January 2014.