Validation of present model

The predictions for stress and strain values of the cross ply models (14, 28 and 56 layered) for 60 N load form a close set (19.06, 19.38 and 19.60 MPa and 1321, 1344 and 1356 μ) and are definite improvement over the analytical results obtained by Guirguitiu et al [2001]. Hence, the present numerical analysis gives a quick convergence of stress and strain values. In the analysis, a crack like initial delamination of 2 mm has been assumed to propagate when the weakest ply is subjected to more than critical stress for that ply. Griffith's criterion for brittle fracture has been used as the matrix is causing propagation of delamination and epoxy is fairly brittle in nature. These results are presented in Figures 34.2, 34.3, 34.4. Some more result are present in Figures 34.5 and 34.6 . Summry is presented in Table 34.2.

Figure 34.2 Convergence of longitudinal stress results on the beam surface under maximum load condition as predicted by various models

Figure 34.3 Convergence of longitudinal strain results on the beam surface under maximum load condition as predicted by various models