Nonlinear Static/Dynamic Analysis Of The Viscoelastic And Viscoplastic Structures With Damage Effects

By considering geometric nonlinearity of the structures, plasticity and viscoelasticity of the material, and damage effect synthetically in the process of the nonlinear static and dynamic analysis for composite material plate, reinforced concrete plate and rockfill dam, a better revealment of the mechanics behaviors of these structures will be obtained. Therefore, the research works of them not only have high theory values, but also mean a lot for engineering applications.In this thesis, based on the Schapery's 3-D constitutive relationship and Kachanov's damage evolution equations, the constitutive model for viscoelastic symmetric cross-ply laminated plates with transverse matrix crack is founded. Then according to the Boltzmann's superposition principle and Von Karman's nonlinear plate theory, the nonlinear dynamic governing equations of the laminated plates considering damage effect are derived. In addition, on the basis of irreversible thermodynamics principle, the damage constitutive relationship and the corresponding damage evolution equations of the anisotropic elastic-brittle materials are established directly from the invariable theory in mathematics. Then according to the Von Karman's nonlinear plate theory, the nonlinear static and dynamic governing equations of the reinforced concrete plates on the two-parameter foundation are gained. What's more, base on the Shen's double yield surfaces model and Merchant's rheological model, the viscoplastic constitutive equations for the rockfill body of the rockfill dam with reinforced concrete surface are founded. Then, considering the coupling effect of the rockfill and the surface, the nonlinear governing equations are founded.Based on the work above, by using the finite difference method and Newmark scheme, the variable functions are separated and these equations are iterated to seek solutions. The nonlinear dynamic responses, the nonlinear amplitude-frequency responses and the chaotic phenomenon of the laminated plate with damage are analyzed. Furthermore, the effects of damage on the nonlinear static and dynamic response of the reinforced concrete structures are also discussed, the research result of which indicate that the value of stiffness coefficients vary with the damage, which result in the distinct change of the nonlinear dynamic response of the structure. In addition, the displacement of the rockfill body and the damage evolution process of the reinforced concrete surface are analyzed. And the contour charts of the vertical displacement and horizontal displacement are drawn respectively, which may provide...