Constitutive Equations in Differential Form for Multiaxial Tension States

4 CONSTITUTIVE EQUATIONS IN DIFFERENTIAL FORM FOR MULTIAXIAL TENSION STATES 

If the dilational and deviatoric components are separated, reasoning similar to that used in the case of integral representation leads to the equations (5, p. 78) 

As Eqs. (5.84) and (5.87) indicate, the tensile modulus and the Poisson ratio are related to the shear and bulk relaxation moduh by the formulae 

Equations (16.32) suggest that these relationships for a viscoelastic material under multiaxial stresses can be written as 

Note that equations similar to Eq. (16.33) hold for the dynamic functions, that is. 

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