A 3-mm-thick composite specimen is tested, as shown in Figure 9.4a, and the compliance, \(s=u / P\), as a function of the half-crack length, \(a\), is shown in Figure 9.9. In a separate test, the critical load for self-sustaining crack propagation, \(P_{\mathrm{c}}\) is measured for different crack lengths, and the critical load corresponding to a crack length \(2 a=50 \mathrm{~mm}\) is found to be \(100 \mathrm{~N}\). Determine the critical mode I strain energy release rate, \(G_{\text {Ic }}\).

Figure 9.4a,

Transcribed Image Text:

(a) u P 2a.