基于XFEM的钢筋混凝土梁开裂数值模拟

Numerical simulation of crack growth of reinforced concrete beam based on XFEM

将扩展有限元法应用于钢筋混凝土简支梁开裂过程的数值模拟,采用三维实体单元与三维杆单元分别模拟混凝土与钢筋,在开裂区域预设与实验值相同间距的初始裂缝,并利用非线性弹簧单元来考虑钢筋与混凝土间的黏结滑移作用,得到了加载过程中裂缝的扩展情况、黏结滑移对裂缝扩展的影响、裂缝宽度与外荷载的关系以及纯弯段内裂缝处混凝土和钢筋中应力的分布.分析结果表明:计算得到的裂缝宽度与实验值吻合较好,黏结滑移会使得同样荷载水平下的裂缝更宽,钢筋和混凝土的应力分布与实际情况相符,扩展有限元不用重划网格、不用预设裂纹扩展路径,能有效地进行钢筋混凝土梁的开裂数值模拟.

The cracking process of a simply supported reinforced concrete beam was simulated by the extended finite element method（XFEM）.The concrete and rebars were simulated by the 3-D solid elements and 3-D truss elements respectively.Initial cracks which kept a same space with the experimental result were predefined.The bond-slip effect between concrete and rebars was considered by the nonlinear springs elements.Based on this,the crack growth state during the loading process,the influence to the crack extension by the bond-slip,the relationship between crack width and external force,as well as the stress distribution of the concrete and rebars in pure bending region were obtained by simulation.The analysis showed that the calculated crack width was in good agreement with the experimental value,bond-slip would make the cracks wider at the same load level,and the calculated stress distributions of the concrete and rebars were consistent with the actual situation.XFEM is an efficient method to simulate the crack of reinforced concrete beam without remeshing and predefining the crack propagation path.