Location

La Jolla, CA

Start Date

1981 12:00 AM

Description

The well-known J integral of elastic fracture mechanics has been related to potential energy-release rate associated with crack extension and has proved to be of great value in fracture testing. In particular, the path-independence of the J integral has been used to an advantage in performing acoustoelastic measurements along a closed contour surrounding a crack tip. In Mode I (opening mode) for example, the J integral depends essentially only on the corresponding stress intensity factor KIwhich can thus be determined.

Actually, J is the component of a vector in the plane of the crack and there exists a component of this vector normal to the crack plane, which, however, has not been interpreted properly in the past. It is one aim of this paper to supply a valid interpretation of this path-independent integral and to relate it to still another integral, also path-independent, which has been termed the L integral. It will be further shown explicitly that for a crack under mixed-mode loading this latter integral represents the energy release rate for rotation which can be used to determine both KI and KII .

Book Title

Proceedings of the ARPA/AFML Review of Progress in Quantitative NDE

Chapter

4. Coupling of NDE and Failure Models

Pages

32-37

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Energy Release Rates for a Plane Crack Subjected to General Loading and their Relation to Stress-Intensity Factors

La Jolla, CA

The well-known J integral of elastic fracture mechanics has been related to potential energy-release rate associated with crack extension and has proved to be of great value in fracture testing. In particular, the path-independence of the J integral has been used to an advantage in performing acoustoelastic measurements along a closed contour surrounding a crack tip. In Mode I (opening mode) for example, the J integral depends essentially only on the corresponding stress intensity factor KIwhich can thus be determined.

Actually, J is the component of a vector in the plane of the crack and there exists a component of this vector normal to the crack plane, which, however, has not been interpreted properly in the past. It is one aim of this paper to supply a valid interpretation of this path-independent integral and to relate it to still another integral, also path-independent, which has been termed the L integral. It will be further shown explicitly that for a crack under mixed-mode loading this latter integral represents the energy release rate for rotation which can be used to determine both KI and KII .