Multidimensional Scale Memory Constitutive Model And Its Validation

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.