Mechanical response of polyvinyl chloride under various stress triaxiality levels

Polyvinyl chloride is a thermoplastic material commonly employed in various engineering applications. The material properties of polyvinyl chloride have been observed to vary significantly with the applied loading conditions. A comprehensive knowledge of the deformation and failure characteristics of the material is necessary for evaluating its performance in engineering applications. In the present work, the stress response of the material is studied by subjecting flat and notched polyvinyl chloride specimens of various geometries to uniaxial tensile testing. The tests were conducted at room temperature and over a range of strain rates, namely 10⁻³, 10⁻², and 10⁻¹ s⁻¹. In addition, tests were also conducted for a range of loading rates from 0.2 to 1.4 mm/s to explore the combined effect of strain rate and stress triaxiality. The results of the experiments indicate a three-stage deformation process of the material: viscoelastic deformation, necking and plastic flow, and a hardening process due to cavitation. An increase in the rate of strain results in an increase in the elastic modulus, yield strength, ultimate strength, and strain at fracture. The geometry of the test specimen also has a strong influence on the results. The effects of stress triaxiality and reduced ductility are related to the radius of curvature of the test specimen. The larger the radius of curvature of the test specimen, the more deformable the material. In addition, these results highlight the interaction between strain rate and stress state on the mechanical response and failure of polyvinyl chloride, providing a solid experimental basis for formulating models for the nonlinear elasto-viscoplastic response of the material.