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中文核心期刊

动态裂纹扩展中的分形效应

FRACTAL EFFECTS OF DYNAMIC CRACK PROPAGATION

  • 摘要: 假设裂纹顶端沿着分形轨迹运动,建立了裂纹扩展的分形弯折(kinking)模型来描述裂纹的动态扩展。根据这个模型,我们推导了分形裂纹扩展对劝态应力强度和裂纹速度的影响.动态应力强度因子与表观应力强度因子之比K(l(t),V)/K(L(t),O)是表观裂纹速度V_O,材料微结构参数(d/Δa),分维D和裂纹扩展路径的弯折角θ的函数。本文研究结果表明:在分形裂纹扩展中,表观(或量测)的裂纹速度V_O很难接近Rayleigh波速C_r.动态断裂实验中V_O明显低于C_r的原因可能是分形裂纹扩展效应所致。材料的微结构,裂纹扩展路径的分维和弯折角均很强地影响动态应力强度因子和裂纹扩展速度。

     

    Abstract: Crack extension paths are often irregular, producing rough fracture surfaceswhich have a fractal geometry.In this paper, crack tip motion along a fractal crack trace isanalysed. A fractal kinking model of the crack extension path is established to describe ir-regular crack growth. A formula is derived to describe the effects of fractal crack propagationon the dvnamic stross intensity factor and on crack velocity. The ratio of the dvnamic stressintensity factor to the applied stress intensity factor,K(l(t),V...

     

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