Finally the applications of CGS method to fracture mechanics are presented in detail,which not only include the optical control equations of variety of crack tip stress singularities for mode I crack,mixed mode crack,V-notch in isotropic material and gradient material,but also show the corresponding simulated and experimental CGS fringe images. The CGS governing equation represents the optics-mechanics relation of the singular yield at crack tip.
By using a complex function method, the complex form of mode I crack tip Jintegral for linear elastic anisotropic fiber composite plate is deducted. The pathindependent of this Jintegral is proved. The concrete computing formula of this Jintegral is obtained.
Based on Eshelby equivalent inclusion theory, a general appromimate solution for predicting the interaction forces of model I crack and an inclusion of arbitrary shape was developed, from which, a set of simplified form of the general solution was also proposed for several special inclusion shapes.
The method in which the whole solution and the local solution is contrasted is applied to deduce the stress intensity factor solution for the model I crack of the orthotropic materials,and then the influence of the materials on the stress intensity is investigated briefly.
Various formulas are used to carryout both corrected and uncorrected calculations on the stress intensity factor K_Ⅰboth of the crack of mode Ⅰ in an infinite plate and of the semielliptic surface crack, correction dimensions of the plastic zone being r_y ≤ 0.08a.