symmetry / strain energy density / free energy density / strain energy density acts / strain-energy function / mechanical energy balance equation / scalar-valued energy function / energy function / strain-energy density / metal plasticity / elastic strain energy density / strain-energy density function / free energy function / elastic law / free energy / elastic constitutive law / internal energy density / energy functions / non-convex energy functions / numerical solutions / strain energy function / energy / strain energy increases / /
4 Constitutive Equations The kinematic equations introduced in Chapter 2 are essential to describe motion and deformation of a body, whereas the local balance equations of Chapter 3 are the differential equations that determine the time evolution of the wanted fields. Altogether