粘聚裂纹扩展的强化有限元h型网格自适应模拟

非连续变形分析和非规则节点处理是基于单元细划的粘聚裂纹扩展网格自适应模拟的关键。首先,利用强化有限单元法中数学单元和物理单元分离的特点,通过引入过渡单元,将适用于非连续变形描述的数学模式覆盖法和方便处理非规则节点的物理模式重构法结合,提出了强化有限单元法的统一关联法则,并导出了相应的单元列式。其次,基于数学裂纹尖端影响域和裂尖单元尺寸,提出了基于强化有限单元法的粘聚裂纹扩展过程模拟的h型网格自适应策略。最后,通过两个算例验证了本文方法的合理性和有效性。

Modelling of cohesive crack propagation using enhanced finite element method via h-adaptive technique

Representation of discontinuities and handling of hanging nodes are two key points of numerical simulation of cohesive crack propagation via h-adaptive technique such as element subdivision.Firstly,a unified correlation rule for enhanced finite element method,as a combination of coverage of mathematical mode,suitable for representing discontinuous displacement field,and reconstruction of physical mode,suitable for dealing with hanging nodes,is proposed by introducing a transitional element between mathematical element and physical element.The corresponding finite element formulas are then derived.Secondly,a scheme for h-adaptivity,with two indexes,i.e.,the influencing radius of mathematical crack tip and the crack-tip mesh size,is put forward for modeling of cohesive crack propagation.The reasonability and effectiveness of the proposed approach is validated against two examples.