【摘要】 Ⅰ-Ⅱ复合型裂纹扩展问题是工程断裂问题中常见的问题,也是断裂力学研究中重要的问题之一。基于复合型裂纹尖端附近等σθεθ线包围区内的体积应变能变化,建立了Ⅰ-Ⅱ复合型裂纹等σθεθ线体积应变能断裂准则,提出了裂纹开裂角公式和断裂扩展条件。应用该断裂准则分别研究了纯Ⅰ型、纯Ⅱ型和Ⅰ-Ⅱ复合型裂纹的开裂角及断裂韧度比随着泊松比的变化规律。此外,给出了复合型裂纹荷载临界比值随裂纹初始角β的变化规律。最后将研究结果与理论预测值和实测值进行了对比,对比结果表明提出的复合型断裂准则物理意义明确,且具有较好的精度。更多还原

【Abstract】 The propagation of I-II mixed mode cracks is a typical one in the engineering fracture problems and a key topic in the fracture mechanics. In the paper a volume strain energy fracture criterion for theⅠ-Ⅱ mixed mode cracks is established based on the changes of the volume strain energy around the crack tips surrounded by isoline σθεθ. Also,the formula of crack initiation angles and crack extension conditions are proposed. The fracture criterion is applied to the investigation of the variation of crack initiation angles of the cracks of ModeⅠ,Mode ⅡandⅠ-Ⅱ mixed mode and the changing rules of fracture toughness ratio with the poisson’s one. In addition,the variations of the load critical ratio with the different initial propagation angle β of cracks are provided. Finally,the comparations of the research results with the theoretical predictions and the measured values are carried out,which shows that the fracture criterion proposed in the paper has the definite physical meaning and the higher accuracy.更多还原