拱坝破坏分析的自适应算法

Adaptive arithmetic of arch dam cracking analysis

本文着重研究拱坝裂纹扩展过程模拟中的有限元分析技术,提出一种高精度和高效率有限元计算的网格动态重新划分策略。在有限元前处理过程中,利用自适应单元把可能破坏的三维单元分为8个和它完全相似的体子单元,把面单元分为4个和它完全相似的面子单元,通过形函数有效地解决自适应剖分过程中的悬点问题,并给出相应的算法和形函数表达式。根据裂缝位置的精度要求,可再次利用自适应单元在细分后的单元基础上再次细分,直至达到工程要求的精度。在有限元计算过程中,通过动态调整荷载步长,使每一荷载步正好有一个单元破坏,从而追踪出拱坝在荷载作用下的破坏位置,实现破坏过程追踪的自适应。最后以某拱坝为例,对裂缝位置和裂缝扩展过程进行了描述。结果表明,本文自适应剖分后的单元规整,计算精度高,稳定性好,可应用于研究拱坝的坝踵应力以及破坏过程研究。

A new dynamic meshing strategy of FEM was proposed to improve the calculation accuracy and efficiency for simulating the crack propagation process in arch dam.In the process of dividing the dam structure and foundation rock into an appropriate amount of discrete finite elements,the adaptive elements were used to divide the original 3-D elements into 8 son-elements analogical to their father-element entirely.The 2-D elements were divided into 4 son-elements analogical to their father-elements entirely too.Th...