Sand Constitutive Modeling And Its Application In LS-DYNA

This dissertation discusses simple anisotropic sand model and cyclic mobility sand model and compares the advantages and disadvantages in simulating monotonic and cyclic loading problems. The experimental results of Toyoura sand and Fuji Sand are used to compare with those of numerical results under drained and undrained stress path in monotonic and cyclic test. By introducing SMP failure criterion, Transformed Stress method is implemented to extend the model into multiaxial space. The experimental results of Ottawa sand and Hostun Sand are used to compare with those of numerical results simulated by transformed stress method and g ?? ? method. Simple anisotropic sand is improved by fabric tensor. The original unique critical state line is modified into non-unique critical state line. This modification is verified by comparison between experimental results of Toyoura, Fuji, Ottawa and Hostun sand and numerical results. The modified constitutive model is planted in general finite element program, LS-DYNA, using numerical algorithm. The single element tests are employed to validate the correctness of model under drained, undrained, monotonic and cyclic stress path. The implementation of the model is achieved by simulating the static and dynamic problems using LS-DYNA. This model reflects the small-strain characteristics in static excavation problems and contributes to analyses of excavation in industrial building. The numerical results are agreed with the observations. Meanwhile, this model analyzes the liquefaction by comparison with pore water pressure and displacement of experiment and numerical process.