大坝有限元分析应力取值的研究

提出了基于误差控制下的自适应网格的有限元应力取值标准:即给定一全局误差限作为自适应有限元网格剖分的准则,以此网格计算所得应力即为有限元应力取值。应用适用于工程计算的Z2后验误差估计方法以及h-型自适应策略,对一个典型的重力坝剖面进行了线弹性自适应有限元计算。计算结果表明:给定一个全局误差限,网格剖分调整若干次后即可满足误差要求,不会出现因角缘应力集中出现剖分不收敛的情况;存在一个全局误差限,使得当继续降低误差限时,坝踵和坝趾的角缘应力趋于稳定值。

STRESS EVALUATION IN FINITE ELEMENT ANALYSIS OF DAMS

The stress evaluation based on adaptive finite element method is discussed. An optimized mesh, which is generated under control of a given global error limit, is used to evaluate stresses. The Zienkiewicz-Zhu a posteriori error estimator and corresponding h-version adaptive strategy are employed. The linear elastic adaptive finite element analysis is applied to a typical gravity dam. Results indicate that error limit is satisfied after several mesh adaptation. There exists a global error limit, which make the stresses at dam heel and toe asymptotically keep stabilization rather than increase without limit. As a global error limit 3% is suggested.