Perturbation of a dynamic crack in an infinite strip
( 1 Department of Mathematical Sciences, University of Liverpool, Liverpool L69 3BX, 2 Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, Cambridge CB3 0WA )
** abm{at}maths.liv.ac.uk
This paper presents an asymptotic analysis of a dynamic problem of two-dimensional elasticity for a crack propagating in an infinite strip. The sides of the elastic strip are subjected to Dirichlet boundary conditions. The crack motion is considered as a steady, constant speed propagation, upon which is superposed a small dynamic perturbation of the crack path, in both horizontal and vertical directions. A WienerHopf problem is solved to evaluate the corresponding dynamic weight functions. Asymptotic representations for the stress-intensity factors are given in terms of the crack-path-perturbation function, the second-order asymptotics of the weight functions and the applied load. These results are then used in the analysis of the crack stability.
Received 20 April 2004. Revise 22 November 2004.