基于隐式梯度公式各向异性混凝土损伤研究.pdfVIP

28 卷 2 期 Vol.28 No.2 工 程 力 学 20 11 年 2 月 Feb. 20 11 ENGINEERING MECHANICS 159 文章编号：1000-4750(2011)02-0159-06 基于隐式梯度公式的各向异性混凝土损伤研究 * 汪忠明，牛晓玉，杨伯源 (合肥工业大学土木与水利工程学院，安徽，合肥 230009) 摘 要 在空间复杂应力状态 ，混凝土损伤表现出强烈的应力方向相关性，隐式梯度公式中标量形式的损伤变 量，不能精确描述混凝土在复杂应力状态 失效问题。该文引入空间有效损伤矩阵，构造一种基于隐式梯度公式 的各向异性的非局部损伤模型，证明了其率平衡方程在损伤过程中类型保持不变，给出空间应力状态 基于该模 型的有限元程序，并将该模型应用于空间复杂应力状态 的混凝土损伤和应变软化的数值模拟。数值计算表明模 型对避免软化损伤模拟时的病态网格依赖性和零能量损耗有非常好的效果。 关键词 损伤；隐式梯度公式；网格依赖性；各向异性；有效损伤矩阵 中图分类号：O346.5 献标识码：A STUDY ON ANISOTROPIC DAMAGE OF CONCRETE MATERIAL BASED ON IMPLICIT GRADIENT MODEL * WANG Zhong-ming , NIU Xiao-yu , YANG Bo-yuan (School of Civil Hydraulic Engineering, Hefei University of Technology, Hefei, Anhui 230009, China) Abstract: In a complex spatial stress state, the concrete damage generally exhibits strongly the dependence of the stress direction. The damage variable in a scalar quantity in the implicit gradient model can not describe accurately the invalid question of concrete in a complex spatial stress state. A new anisotropic nonlocal damage model based on the implicit gradient model is constructed by introducing an effective damage matrix. It is proved that the rate equilibrium equations remain elliptic. The finite element program based on the model is presented in a complex spatial stress state. The model is applied to numerical simulation of damage of concrete in a complex spatial stress state. The numerical results show that the model can overcome the pathological mesh dependence and zero energy consuming when the strain-softening phenomenon of concrete material is simulated. Key words: damage; impli