Mechanics of dynamic debonding.

*(English)*Zbl 0726.73058Summary: Singular fields around a crack running dynamically along the interface between two anisotropic substrates are examined. Emphasis is placed on extending an established framework for interface fracture mechanics to include rapidly applied loads, fast crack propagation and strain rate dependent material response. For a crack running at nonuniform speed, the crack tip behaviour is governed by an instantaneous steady-state, two- dimensional singularity. This simplifies the problem, rendering the Stroh techniques [A. N. Stroh, J. Math. Phys. 41, 77-103 (1962; Zbl 0112.168)] applicable. In general, the singularity oscillates, similar to quasi-static cracks. The oscillation index is infinite when the crack runs at the Rayleigh wave speed of the more compliant material, suggesting a large contact zone may exist behind the crack tip at high speeds.

In contrast to a crack in homogeneous materials, an interface crack has a finite energy factor at the lower Rayleigh wave speed. Singular fields are presented for isotropic bimaterials, so are the key quantities for orthotropic bimaterials. Implications on crack branching and substrate cracking are discussed. Dynamic stress intensity factors for anisotropic bimaterials are solved for several basic steady state configurations, including the Yoffe, Gol’dshtein and Dugdale problems. Under time- independent loading, the dynamic stress intensity factor can be factorized into its equilibrium counterpart and the universal functions of crack speed.

In contrast to a crack in homogeneous materials, an interface crack has a finite energy factor at the lower Rayleigh wave speed. Singular fields are presented for isotropic bimaterials, so are the key quantities for orthotropic bimaterials. Implications on crack branching and substrate cracking are discussed. Dynamic stress intensity factors for anisotropic bimaterials are solved for several basic steady state configurations, including the Yoffe, Gol’dshtein and Dugdale problems. Under time- independent loading, the dynamic stress intensity factor can be factorized into its equilibrium counterpart and the universal functions of crack speed.

Reviewer: Reviewer (Berlin)

##### MSC:

74R99 | Fracture and damage |

74G70 | Stress concentrations, singularities in solid mechanics |

74S30 | Other numerical methods in solid mechanics (MSC2010) |

74E10 | Anisotropy in solid mechanics |

74B10 | Linear elasticity with initial stresses |

35Q72 | Other PDE from mechanics (MSC2000) |

15A23 | Factorization of matrices |