โ Scribed by Heping Xie; David J. Sanderson
No coin nor oath required. For personal study only.
Crack extension paths are often irregular, producing rough fracture surfaces which have a fractal geometry. In this paper, crack tip motion along a fractal crack trace is analysed. A fractal kinking model of the crack extension path is established to describe irregular crack growth. A formula is derived to describe the effects of fractal crack propagation on the dynamic stress intensity factor and on crack velocity. The ratio of the dynamic stress intensity factor to the applied stress intensity factor K(L(D, t), V)/K(L(t), 0), is a function of apparent crack velocity Vo, microstructure parameter d/Aa (grain size/crack increment step length), fractal dimension D, and fractal kinking angle of crack extension path O. For fractal crack propagation, the apparent (or measured) crack velocity Vo, cannot approach the Rayleigh wave speed Cr. Why Vo is significantly lower than Cr in dynamic fracture experiments can be explained by the effects of fractal crack propagation. The dynamic stress intensity factor and apparent crack velocity are strongly affected by the microstmcture parameter (d/Aa), fractal dimension D, and fractal kinking angle of crack extension path O. This is in good agreement with experimental findings.
๐ SIMILAR VOLUMES
In this paper, analytical and numerical simulations of the crack-tip stresses are presented. Analytical calculations are performed utilizing modified Rice and elastic equations. 2D finite element analyses (FEA) are conducted in parallel using ANSYS. Results from both methods are compared and discuss
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