混凝土的一种梨形边界面本构模型  

A pear-shaped bounding surface constitutive model for concrete

作　　者：张静[1] 王哲[1] ZHANG Jing;WANG Zhe(School of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China)

机构地区：[1]北京交通大学土木建筑工程学院,北京100044

出　　处：《哈尔滨工业大学学报》2018年第8期142-149,共8页Journal of Harbin Institute of Technology

基　　金：国家自然科学基金(51279003;51078024)

摘　　要：为研究混凝土材料在多轴循环荷载作用下的非线性特性,基于经典塑性力学理论和边界面模型理论,提出一个改进的边界面模型.模型中,屈服面为封闭、光滑曲面,在子午面内为梨形;边界面与屈服面的形状相似;选择应力的第一不变量和应变偏量作为屈服面函数中的自变量;相应的加卸载判据中的微分变量也是上述两种变量;根据屈服面和边界面形状的相似性,通过比例关系定义映射法则;对于处在屈服面上的任意一个当前应力点,根据此法则,都能够找到与之对应的处在边界面上的映射点,两个点对应的曲面法线方向相同;采用非相关流动法则描述塑性变形.对沿着偏平面上的压缩方向,对混凝土试块分别进行单调加载和循环加载时的试验结果,用本构模型进行模拟,模型计算结果与试验结果吻合.模型能够统一地描述应力-应变曲线的上升-下降段,能够描述剪胀现象.To investigate the nonlinear properties of concrete under multiaxial cyclic loading,an improved bounding surface model was presented for concrete within the framework of elastoplastic and bounding surface theory. The yield surface is closed and smooth,and in tensile and compressive meridan planes,the yield surface is a pear shape. The shape of bounding surface is similar to yield surface. The first stress invariant and the strain deviation were adoped as the independent variables in the yield function and as the differential variable in the loading and unloading criteria. Based on the similarity of the shape between yield and bounding surfaces,the mapping relations were determined by proportional relations. According to the mapping rules,there always was an image stress point on the bounding surface for a current stress point on the yield surface. The two points had the same normal direction for corresponding surfaces,and a nonassociated flow was adopted to describe the plastic deformation. For the experimental results of concrete specimens under monotonic and cyclic loading along the compression direction in the deviatoric plane,the proposed model was used to simulate the results numerically. The calculated results agree well with experimental data. The model can describe the pre-failure and post-failure stress-strain curve and describe the shear dilatancy of concrete.

关 键 词：循环荷载 边界面模型 映射法则 剪胀 偏平面 

分 类 号：O344.3[理学—固体力学] TU528.01[理学—力学]