A thermo-mechanical cohesive zone formulation for ductile fracture
A thermo-mechanical cohesive zone formulation for ductile fracture
复制标题
DOI：
10.1016/j.jmps.2008.06.002
复制
发表时间：
2008-10
影响因子：
5.3
通讯作者：
M. Fagerström;R. Larsson
中科院分区：
文献类型：
--
作者：
M. Fagerström;R. Larsson
本文讨论了将与断裂过程区有关的机械现象和热现象都投射到粘合区中的可能性。因此，对内聚区概念的更广泛解释建议不仅包括由于微裂纹引起的应力退化，还包括热量产生和能量传输。根据我们的经验，这种扩大内聚区的概念允许更有效的塑性断裂有限元模拟。该公式的关键特征涉及热-机械内聚区模型，该模型在热-超弹塑性连续体中演化，允许同时模拟由于断裂过程产生的热量和穿过断裂过程区域的热量传递。这是通过热力学参数来实现的，得到运动控制方程、能量方程和本构方程的耦合。因此，根据位移场的独立连续部分和不连续部分来定义变形图。此外，作为位移运动学的扩展，为了表示与断口界面上的不连续热流相关的温度场，提出了一个包含界面（或带）温度的匹配的不连续温度场。在第一个数值例子中，关于热超弹塑性材料的动态准脆性裂纹扩展，我们捕获了由于能量耗散断裂过程而导致裂纹表面附近温度的初始升高。在第二个例子中，考虑了韧性断裂模拟在高速（绝热）切削过程中的新应用，其中观察到一些随切削速度变化的一般趋势。
The paper addresses the possibility to project both mechanical and thermal phenomena pertinent to the fracture process zone into a cohesive zone. A wider interpretation of the notion cohesive zone is thereby suggested to comprise not only stress degradation due to micro-cracking but also heat generation and energy transport. According to our experience, this widening of the cohesive zone concept allows for a more efficient finite element simulation of ductile fracture. The key feature of the formulation concerns the thermo-mechanical cohesive zone model, evolving within the thermo-hyperelastoplastic continuum, allowing for the concurrent modelling of both heat generation, due to the fracture process, and heat transfer across the fracture process zone. This is accomplished via thermodynamic arguments to obtain the coupled governing equation of motion, energy equation, and constitutive equations. The deformation map is thereby defined in terms of independent continuous and discontinuous portions of the displacement field. In addition, as an extension of the displacement kinematics, to represent the temperature field associated with the discontinuous heat flux across the fracture interface, a matching discontinuous temperature field involving the interface (or band) temperature is proposed. In the first numerical example, concerning dynamic quasi-brittle crack propagation in a thermo-hyperelastoplastic material, we capture the initial increase in temperature close to the crack surface due to the energy dissipating fracture process. In the second example, a novel application of ductile fracture simulation to the process of high velocity (adiabatic) cutting is considered, where some general trends are observed when varying the cutting velocity.