用连续-非连续方法分析混凝土梁的破坏过程

CONTINUOUS-DISCONTINUOUS METHOD FOR FAILURE PROCESS OF CONCRETE BEAM

采用有限元形函数作为单位分解函数,位移间断用富集节点的附加自由度表示,建立了允许在单元内部位移间断的连续、非连续模型。非连续位移的扩展路径完全与网格结构无关。不同于以非协调应变为基础的嵌入非连续模型,对单元的类型没有限制而且间断位移可以贯穿单元边界,与扩展有限元方法在构造上也有本质的区别。结合粘结裂纹模型,对混凝土梁在剪切作用下的断裂过程模拟说明了该方法的有效性。

Using finite element shape function as partitions of unit, the displacement jump across a crack is represented by extra freedom degree of enriched node. Continuous-discontinuous displacement model allowing the displacement of internal element discretion is developed. The expansion path of discontinuouos displacement is completely independent of the mesh structure. Unlike so-called embedded enhanced discontiniuity model, which is based on incompatible strain, there is no restriction on the type of underlying solid finite element that can be used and displacement jumps are continuous across element boundaries. Physical concept of the model is also different from that of the extended finite element method. Combined with cohesive crack model, the effectiveness of the proposed approach is demonstrated by simulating the fracure process of concrete beam under shear loads.