Study On A Kind Lagrange Form Of Infinitesimal Deformation Elastic-plastic Model For Singular Yield Surface And Application

The situation of singular yield surface are very common in the research on constitutive relation of Engineering Materials, for example, two-yield-surface soil model, the four-parameter concrete model. .But the theory of elastic-plastic s constitute relation is generally suitable for regular yield surface. but is not suitable for singular yield surface .This paper discusses the Lagrange finite def ormation elastic-plasticity theory. at situation of infinitesimal strain These work s are introduced as follows:1. This paper discusses basic theories of constitutive model of the Lagrange finite deformation elastic-plasticity. and we chiefly derive the yield function,loading unloading criterion,constitutive equation of constitutive models of elastic-plasticity for singular yield surface at situation of infinitesimal strain, then introduces the special constitutive models of isotropic elastic-plasticity, and all calculating formula of elastic-plasticity is derived on finite element calculating. Finally, all the software about finite element is designed by matlab and an example is calculated, proficiency testing of Anasys Engineering Software. The theoretical results can describe the special constitutive models of isotropic elastic-plasticity, and can describe the stress response of material.2. Elastic-plasticity constitutive model of geo-materials is generally based on p-q space coordinate system. The p-q space coordinate system is transformed to the principal stress space coordinate system, and the principal stress space coordinate system is transformed to the rectangular space coordinate withπplane and normal line by linear transformation. In the next, The geo-materials double yield constitutive model assembled by the geo-materials of D-P cap model and the geo-materials of Modified Cambridge Model. Within the classical elastic-plastic theory system, constitutive equation of Geo-materials double yield constitutive model is derived by constitutive models of elastic-plasticity for singular yield surface at situation of infinitesimal strain...