An iterative method for laser scanning path was presented to induce and control a crack propagating along a predetermined asymmetric trajectory in a brittle plate, and the effects of control parameters on the convergence were investigated. Based on PID control theory, an iterative formulation for laser scanning path was developed, which is composed of the deviation of crack from the predetermined trajectory and its integral and differential. The deviation of crack was evaluated by the crack propagation angle calculated from the simulation of enforced crack growth along the predetermined line, which avoiding the adaptive crack propagation analysis and the corresponding finite element remeshing. Path iterative analysis for typical examples was carried out by choosing various control parameters of proportion, integral and differential. Results show that the proportion parameter has obvious influence on the convergence, and the relative greater value is advantageous, while the differential control parameter needs to be small enough. Furthermore, adaptive crack propagation simulation shows that the crack propagation can be induced and controlled along a predetermined trajectory as the laser scanning along the converged path, which demonstrates the validity of the present method．
YANG Xin-Wang, BI Guo-Li, ZHANG Xue, et al. Path iterative method for laser-controlled crack propagation and its convergence. J4, 2009, 43(11): 2043-2047.
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