On the Extension of The Jr Concept to Significant Crack Growth

A possible method of estimating the extra work required in real elasto-plastic fracture as compared with a hypothetical non-linear elastic specimen is discussed. It is shown how the extra work term can be used to calculate the specific essential work, R., from J r obtained by the standard ASTM method. Although the method presented apparently underestimates the extra work, it points a way forward to obtain the true crack growth resistance.