Application of Linear Viscoelastic Continuum Damage Theory to the Low and High Strain Rate Response of Thermoplastic Polyurethane

Background Understanding the mechanical response of elastomers to applied deformation at different strain rates and temperatures is crucial in industrial design and manufacture; however, this response is often difficult to measure, especially at high strain rates (e.g. > 100 s(- 1)), and more predictive methods to obtain constitutive relationships are required. Objective The objective of the research described in this paper is to develop such methods. Method The paper outlines a novel approach combining quasi-static monotonic tests in tension and compression, quasi-static cyclic tests in tension, and high strain rate tests in compression, with dynamic mechanical analysis and time-temperature superposition. A generalized viscoelastic model incorporating continuum damage is calibrated. Results The results show that a model calibrated using data from quasi-static compression and dynamic mechanical analysis can be used to adequately predict the compressive high strain rate response: hence, this paper provides an important step in the development of a methodology that avoids the requirement to obtain constitutive data from high strain rate experiments. In addition, data from FE models of the dynamic mechanical analysis experiments are provided, along with a discussion of data obtained from tensile and cyclic loading. Conclusions The paper demonstrates the effectiveness of 'indirect' predictive methods to obtain information about high rate behaviour of low modulus materials.