Experimental investigation and modeling of the rate-dependent deformation behavior of PMMA at different temperatures

Abstract

Numerical and experimental studies on the nonlinear mechanical properties of PMMA under uniaxial compression are conducted over the temperature range of −70°C to 120°C and the strain rate range of 10−4–103/s. The stress–strain curves of PMMA samples are obtained under different strain rates and temperatures, and compressive deformation characteristics of the materials are discussed. The variation law of the yield stress and yield strain with temperature and strain rate is analyzed. The experimental results show the mechanical properties of PMMA in finite deformation are strongly affected by temperature and strain rate. As the temperature increases, the yield stress of PMMA decreases linearly, and the yield strain decreased exponentially. The yield stress of PMMA obviously increases with the increasing of logarithmic strain rate, and shows the characteristics of bilinear relation. Based on the thermodynamic derivation methods, a thermo-viscoelastic constitutive model describing the nonlinear stress-strain behavior of PMMA is proposed in this paper. The model takes into account the coupling effects of strain rate and temperature. The experimental verification and error analysis show that the model is capable of accurately representing the nonlinear stress-strain behavior of PMMA at different strain rates and temperatures.