Energy Absorption Capacity of Agglomerated Cork Under Severe Loading Conditions

Abstract

Understanding the mechanical behavior of materials in working conditions is a current problem in transport industries. In this article, we demonstrate why the temperature and the strain-rate are first-order parameters when studying the mechanical behavior of polymeric cellular materials with a glass transition temperature Tg in working temperatures. Compressive tests in quasi-static until a 0.5 hencky strain were conducted at several temperatures on agglomerated cork. Compressive tests were then conduted along a large range of strain rates, from 4.2 10−5 s−1 to 250 s−1 at room temperature (24 °C). Both parameters influence strongly the overall mechanical behavior with an opposite effect because of the polymeric nature of the constitutive materials. However discrepencies in the variation were observed between materials parameters of the two conditions (temperature and strain rate). In order to separate the dynamic effects from the modification of the stiffness of the constitutive materials with temperature or strain rate, a specific apparatus was designed to achieve high-strain rate tests in temperature. Compressive tests in dynamic regime were then conducted at −20 °C on agglomerated cork as a proof-of-concept. The experimental results (stress/strain curves and materials parameters) showed a great influence of the strain-rate and the temperature combined. Such apparatus will provide results allowing a more in-depth characterisation of the local mechanisms that will be precious for future simulations.