Issue 43

L.C.H. Ricardo, Frattura ed Integrità Strutturale, 43 (2018) 57-78; DOI: 10.3221/IGF-ESIS.43.04 69 Figure 7 : Center Crack Panel, Newman [29]. Figure 8 : Finite Element Model of Center Crack Panel Newman [29]. mesh K T  a ( mm ) elements Nodes I 7.2 0.64 398 226 II 14.4 0.16 533 300 III 20.9 0.08 639 358 Table 3 : Mesh at Crack Tip (W = 460.0 mm and a  28.0 mm). Figure 9: Constant Amplitude Crack Extension [29]. Fig. 9 displays how is obtained the stabilization of opening stress during crack propagation. The best agreement with experimental results was mesh II, although mesh III provides also good results. Nowadays, with the computer facilities, the time to evaluate this mesh is reduced, and the size of the element and the increment are mostly used today to evaluate