Determination of shear creep compliance of linear viscoelastic-plastic solids by instrumented indentation

This paper presents a convenient method which is referred to as “Revised Step-Hold” method for determination of shear creep compliance of linear viscoelastic-plastic solids using instrumented indentation. Its main idea is using the revised load-depth curve which does not contain plastic deformation to determine the shear creep compliance instead of using the measured load-depth curve. The revised load-depth curve can be obtained through a three-step procedure. Applications are illustrated on two typical viscoelastic-plastic solids, namely PMMA and UPVC. The shear creep compliance of PMMA and UPVC determined by the revised step-hold method has satisfactorily good agreement with the corresponding uniaxial tensile result. Therefore, it demonstrates that the revised step-hold method is a reliable method for determination of shear creep compliance of linear viscoelastic-plastic solids.