This paper generalizes one-dimensional constitutive equations for rate-sensitive plastic materials to general stress states. The dynamic yield conditions for elastic, visco-plastic materials are discussed, and new relaxation functions are introduced. Solutions of the relaxation equations for such materials are provided. The paper begins by introducing the constitutive equations for rate-sensitive plastic materials, which are derived from the statical yield function and involve the strain rate. The equations are generalized by replacing the original terms with a function Φ(F), which depends on the yield function F. The resulting equations describe the relationship between strain rate and stress, considering both elastic and visco-plastic components. The paper then discusses the relaxation process for general stress states, introducing a boundary value problem that models the relaxation of stress and strain. The relaxation equations are derived, and their solutions are presented using iterative methods. The equations are shown to describe the behavior of materials under dynamic loading, with the yield condition depending on strain rate. The paper also considers special forms of the function Φ(F), such as Φ(F) = F^δ and Φ(F) = exp(F) - 1, which lead to different constitutive equations for materials. These equations are shown to describe various strain rate laws, including the Cowper-Symonds-Bodner law and Sokolovskii's strain rate law. The paper concludes by discussing the generalization of the constitutive equations to materials with more complex yield functions, such as those involving the third invariant of the stress deviation. The solutions of the relaxation equations are presented in terms of iterative methods, and the results are shown to be consistent with experimental data. The paper also references several previous works and experiments that support the theoretical developments presented. The author acknowledges the contributions of other researchers and provides a bibliography of relevant literature.This paper generalizes one-dimensional constitutive equations for rate-sensitive plastic materials to general stress states. The dynamic yield conditions for elastic, visco-plastic materials are discussed, and new relaxation functions are introduced. Solutions of the relaxation equations for such materials are provided. The paper begins by introducing the constitutive equations for rate-sensitive plastic materials, which are derived from the statical yield function and involve the strain rate. The equations are generalized by replacing the original terms with a function Φ(F), which depends on the yield function F. The resulting equations describe the relationship between strain rate and stress, considering both elastic and visco-plastic components. The paper then discusses the relaxation process for general stress states, introducing a boundary value problem that models the relaxation of stress and strain. The relaxation equations are derived, and their solutions are presented using iterative methods. The equations are shown to describe the behavior of materials under dynamic loading, with the yield condition depending on strain rate. The paper also considers special forms of the function Φ(F), such as Φ(F) = F^δ and Φ(F) = exp(F) - 1, which lead to different constitutive equations for materials. These equations are shown to describe various strain rate laws, including the Cowper-Symonds-Bodner law and Sokolovskii's strain rate law. The paper concludes by discussing the generalization of the constitutive equations to materials with more complex yield functions, such as those involving the third invariant of the stress deviation. The solutions of the relaxation equations are presented in terms of iterative methods, and the results are shown to be consistent with experimental data. The paper also references several previous works and experiments that support the theoretical developments presented. The author acknowledges the contributions of other researchers and provides a bibliography of relevant literature.