论文标题
开裂元素方法的基于直接耗散的弧长方法
Direct dissipation-based arc-length approach for the cracking elements method
论文作者
论文摘要
耗散的能量代表非线性断裂力学中单调增加的状态变量,可以用作追踪耗散的限制,而不是结构响应的弹性卸载路径。在这项工作中,与使用内部能量和外部载荷完成的其他基于能量的方法相比,提出了一种新型的弧长方法。它利用了裂纹元件的全局/扩展方法,直接基于裂纹的开口和裂纹(位移跳跃和凝聚力)直接提取消散的能量(位移跳跃和凝聚力)。它的线性化形式是开发的,并且通过Sherman-Morrison公式自然获得了弧长约束的刚度因子。一旦出现了粘性裂纹,就可以采用所提出的方法,直到大部分断裂能消散为止。介绍了几个数值测试的结果,其中介绍了弧长控制和自传播裂纹的结果。他们证明了所提出的方法的鲁棒性,该方法捕获了带有多个裂纹的负载结构的全局和局部峰值载荷以及力 - 置换响应的所有扣子。
Dissipated energy, representing a monotonically increasing state variable in nonlinear fracture mechanics, can be used as a restraint for tracing the dissipation instead of the elastic unloading path of the structure response. In this work, in contrast to other energy-based approaches that use internal energy and the work done by the external loads, a novel arc-length approach is proposed. It directly extracts the dissipated energy based on crack openings and tractions (displacement jumps and cohesive forces between two surfaces of one crack), taking advantage of the global/extended method of cracking elements. Its linearized form is developed, and the stiffness factor of the arc-length restraint is naturally obtained by means of the Sherman-Morrison formula. Once cohesive cracks appear, the proposed approach can be applied until most of the fracture energy is dissipated. Results from several numerical tests, in which arc-length control and self-propagating cracks are jointly used, are presented. They demonstrate the robustness of the proposed method, which captures both global and local peak loads and all snap-back parts of the force-displacement responses of loaded structures with multiple cracks.