Issue 35

S S. El Kabir et alii, Frattura ed Integrità Strutturale, 35 (2016) 64-73; DOI: 10.3221/IGF-ESIS.35.08 68 1 s G and 2 s G are the critical values of the energy release rate in each mode respectively. They are parameters depend your material characteristics. The factor k is the mixed mode ratio equal to 1 in the present work. According to equation (7), the crack growth process obeys to the three different cases:  Crack growth initiation f < 1  Crack growth stability f = 1 and 0 f a     Crack growth instability f > 1 and 0 f a    where a is the crack length. N EW SPECIMEN DIMENSIONS AND CRACK GROWTH STABILITY Design and geometry n order to prove the efficiency of new specimen, various size and thickness parameters of MMCG are presented in Fig. 4 for mixed loading mode at 45°. Figure 4 : Geometric definition of MMCG specimen for: (a) : different size coefficients a, (b) : different thicknesses coefficients b and (c) : a combination of both. I