Research On The Application Of Thermal Elastoplasticity Constitutive Equations In Tensor Function

Because of its excellent high temperature resistance,alloy materials have been widely applied in aerospace,navigation,nuclear power generating units and other high temperature environments.Thermal elastoplastic constitutive relationship of materials has become an important issue in the application of alloy materials.The internal structure changes of alloy materials at different deformation temperatures are different,leading to a great difference in their stress strain curves.At present,the approximate exponential and hyperbolic nonlinear constitutive equations are established in some form of deformation,and their usability and accuracy are not satisfactory.The polynomial constitutive equation based on tensor function representation theorem plays an important role in the study of deformable body mechanics.Due to the symmetry of isotropic,transversely isotropic and orthotropic materials,the constitutive equations expressed by tensors have special forms.It is necessary to study the number and type of the coefficient of the nonlinear constitutive equation with symmetric characteristic material,as the coefficient of the constitutive equation expressed by a polynomial requires the completeness of the irreducibility.In this paper,the ElastoPlastic constitutive equations of isotropic materials represented by Tensor function polynomials are applied to the study of high temperature ElastoPlastic deformation of isotropic alloy materials.Inconel600 alloy and AZ31 magnesium alloy were selected to carry out high temperature tensile(compression)experiments.The experimental data were replaced in the unidirectional tension(pressure)constitutive equation,and the elastoplastic coefficient at different temperatures was calculated.After analysis,it is found that for different types of deformation,the number of elastic plastic coefficient is not zero,but the number of the thermal elastoplastic coefficient is the same for the same deformation at different temperatures.And for the same type of thermal deformation,the elastoplastic coefficient of two temperatures in the narrower temperature range is known.By linear calculation,the elastoplastic system value at any temperature in the temperature range can be estimated,and the degree of bonding is higher by comparing with the experimental data.