Section 9.10 - Unified Disturbed State Constitutive Models

Abstract

The disturbed state concept (DSC) is a unified approach for constitutive modeling of materials and interfaces and joints under thermomechanical and environmental loading. It allows one to consider, in a hierarchical framework, various behavioral features of materials, such as elastic, plastic, and creep strains, microcracking leading to degradation or damage, and stiffening or healing. Degradation and stiffening are incorporated by using the idea of disturbance. The DSC and its specialized versions are found to provide a satisfactory characterization of a wide range of materials, such as geologic, concrete, asphalt concrete, ceramics, metals, allows (solders), and silicon. The DSC model allows for the flexibility to choose specialized versions, such as the elastic, elastoplastic, viscoplastic, and disturbance. Hence, the user needs to specify parameters related to the version chosen for agiven material and application need. The basic parameters are linear elastic, plasticity, creep, disturbance, thermal effect, yield function, growth function, creep, and temperature dependence. The DSC model is implemented in linear and nonlinear finite element procedures for the solution of problems under static, dynamic, and repetitive loading, and involving dry and porous saturated materials.