基于扩展有限元的地质聚合物混凝土断裂过程研究

扩展有限元法是基于常规有限元框架分析裂纹等不连续力学问题的一种有效数值方法,在常规的有限元位移表达式中,增加了能够反映位移不连续性的跳跃函数和渐进缝尖位移场函数来对不连续结构附近的节点自由度进行局部加强。本文介绍了扩展有限元法及粘聚力模型的基本原理,给出了基于扩展有限元法的地质聚合物混凝土断裂过程分析方法。分别采用四种不同的软化曲线对I型缺口地质聚合物混凝土梁从裂纹萌生、扩展直至断裂破坏的全过程进行了模拟,并基于双K断裂准则分析了其断裂韧性。结果表明,Petersson模型与试验结果吻合较好,最后基于模拟结果进一步揭示了断裂过程区的演化过程。

Investigation of fracture process in geopolymer concrete using the extended finite element method

The XFEM (Extened Finite Element Method) is an effective numerical Method for analyzing discrete mechanical problems such as cracks based on the conventional Finite Element framework.In the conventional finite element displacement expressions,jump function and progressive tip displacement field function are added to enhance the degree of freedom of the nodes near the discontinuities.The XFEM and CZM (Cohesive zone Model) are introduced and a fracture process analysis method of GPC (Geopolymer concrete) based on the XFEM is proposed in this study.Four different softening curves were used to simulate the whole process of the GPC beam from crack initiation,to expansion till fracture failure,and its fracture toughness was determined based on the double-k fracture criterion.The results show that the Petersson model was in good agreement with the experimental results,and the evolution process of FPZ (Fracture Process Zone) was finally revealed based on the simulation results.