多维量化记忆本构模型及其验证

【作者】 许艳林；

【导师】 迟世春；

【作者基本信息】 大连理工大学 ， 水工结构工程， 2004， 硕士

【摘要】 一维量化记忆模型(SM)以经典的弹塑性模型为基础，将土体在单调加载情况下应力应变曲线的非线性剪切模量变换成量化模量在几何空间上的分段线性分布，这种变换建立了剪切模量与量化模量的映射关系。再以Masing准则为基础，在循环加载情况下，对这种简化后的几何分布进行变化调整，生成分段线性的量化模量。在进行土工结构动力计算时，可根据应力条件通过线性插值确定量化模量，再运用映射关系确定非线性的剪切模量。从而将剪切模量的非线性问题转化为量化模量的分段线性问题来处理，大大简化了非线性计算的复杂性。 本文将一维量化记忆模型中的记忆点对扩展为偏平面上的记忆面，将量化模量定义为当前应力点与破坏面之间距离的函数，构造了多维量化记忆模型(MDSM)，推导了多维应力条件下的本构关系。采用与一维量化记忆模型相同的映射函数来计算过程中塑性模量的变化。 在本构关系的数值实施中，利用大型非线性有限元软件ABAQUS提供的用户自定义接口平台，编写子程序UMAT，实现了多维量化记忆本构积分模块。最后对某大三轴试验进行了有限元模拟，得到的计算曲线与试验结果一致。因此，本文提出的多维量化记忆模型及其算法是可行的及合理的。更多还原

【Abstract】 In this thesis, one-dimensional scaled memory(SM) model is introduced comprehensively for dynamic nonlinear analysis of soil structure. The SM translate the nonlinear variation of tangential modules during monotonic loading into a piecewise linear distribution geometrical relationship, which can easily be modified to simulate hysteretic characteristics of soil behavior during cyclic loadings, it also can simulate the dynamic stress-strain response of arbitrary cyclic loadings. The SM is applied to eliminate artificial ratcheting in bounding surface plasticity, and to produce closed stress-strain loops during cyclic loadings, without introducing a single material constant.A multi-dimensional scaled memory (MDSM) model for pressure-dependent materials, based on the concept of scaled memory, is constructed. The constitutive relationship is deduced. In this thesis, the each dipole of memory points in one-dimensional SM would be generalized as a memory surface in multi-dimensional stress space for MDSM, the scaled modulus is defined as a function of distance between the current stress point and failure surface, and the mapping function of one-dimensional stress-strain relationship is adopted in the MDSM.The constitutive integration module is completed through the user subroutine UMAT in numerically implementing of the proposed constitutive model, which based on the big nonlinear FEM software ABAQUS, and it will be applied for the dynamic nonlinear analysis of soil structure under multidimensional stresses. To simulate the dynamic triaxial test process with 300mm diameter’s specimen, the dynamic stress-strain curves were agreement between calculation by MDSM and test results. It is demonstrated that the dynamic stress-strain relationship could be simulated commendably by multi-dimensional scaled memory model and its arithmetic.更多还原