基于等效损伤单元模型的高混凝土坝损伤开裂演化分析

Damage Simulation of High Concrete Dams Based on Equivalent Damage Element Model

基于宏观均质假定考虑混凝土细观非均质性的影响,推导了一种等效损伤单元,该单元具有类似于普通有限单元的均质特性但尺寸处于相对高坝的细观层次,采用最大拉应力与摩尔-库仑破坏准则作为损伤阈值,并发展增量形式的动力非线性迭代算法为计算分析工具;基于ANSYS平台,以UPFs为二次开发工具,在通用有限元软件中实现了考虑混凝土非均质特性的高坝损伤开裂演化模型的嵌入;通过Koyna重力坝的典型损伤破坏形式验证了所开发计算模型的可靠性和良好的工程实用性,并通过单元网格尺寸的优化分析,提出了适用于工程应用的最佳方案。

Based on the macroscopic homogeneous assumption,the dynamic performance of the high concrete dam can be simulated effectively by considering the influence of mesoscale heterogeneity of concrete,which can be implemented by finite element method.So it has great practical value that generalizes the method to engineering application.Firstly,ED element was used to disperse high concrete dam,and concrete heterogeneity characteristics were considered by adopting Weibull distribution of material parameters.Meanwhile,maximum tensile strain criterion and Mohr-Coulomb criterion were chosen as the damage threshold,and incremental dynamic nonlinear iterative algorithm was used as calculation and analysis tools.Secondly,a damage evolution model of high concrete dam was presented with considering the heterogeneity of concrete,which is based on UPFs for establishing the ED element within commercial finite element software ANSYS.Finally,to justify the applicability and correctness of the proposed method for engineering purpose,seismic response analysis of Koyna Gravity concrete dam was presented.In addition,the optimum design scheme was given through the optimization analysis of unit grid size.