J-Integral Analysis of the Compact Tension Specimen

A J-integral solution is presented for the compact tension specimen. The solution allows analysis for crack lengths greater than 20 percent of the specimen width. Unlike previous solutions that were based on the assumptions of full ligament yielding, deeply cracked specimen, or limit load, this paper derives a J solution that does not require such assumptions. Solutions are presented for both the deformation theory J and modified J, JM. These solutions are suitable for J-resistance curve development. A relationship between the plastic and the elastic η factor is presented. A comparison of the present solution with earlier solutions indicates that the J for those solutions is underestimated for a/W below 0.5. Numerical results show that Jd and JM resistance curves are closer than previously obtained. A criterion for extrapolating J-resistance curve is proposed. A relationship for scaling load-displacement curves suitable for key curve analysis is also presented.