CREEP CONSTITUTIVE EQUATION AND EXPERIMENTAL DETERMINATION OF COMPOSITE MATERIALS PartⅡ:Experimental Determination

The constitutive equations of composite materials have been obtained in the first part of this paper.Based on the previous study, the modified form of constitutive equation of creep deformation is given in this part.The strain in two stages of creep and recovery are experimentally recorded,which is used to determine the parameters of the constitutive equation,In view of the complexity of the nonlinear equation,this paper proposed a method to determine the parameters,in which the least-square-error method is used in conjunction with the discreteness of variables.Then the theoretical formulas are modelled by data fitting and each kind of strains is separated.Finally,based on a few of available experimental data,the three parametric functions of stress in the constitutive relationship obtained.