An experimental and modeling study of the thermomechanical behavior of an ABS polymer structural component during an impact test

Abstract

An experimental and modeling study of the thermomechanical behavior of an ABS polymer structural component during an impact test is presented. The structural component was a heel of a woman's shoe made of ABS polymer material reinforced or not by a pin. Kinematics and thermal full field measurement techniques were used to observe the material and structural component during preliminary experimental tensile and impact tests. With the kinematic fields it was possible to identify the stress–strain response, which takes the necking localization into account. Positive volume variations were also observed during these tensile tests, which were associated with the crazing damage mechanisms in this type of polymer. The thermal fields measured during these tests showed high temperature variations (a few K to 25 K) in the zone where strain was localized. The associated thermal softening, estimated by the stress–strain responses at various imposed room temperatures, was taken into account in the Johnson Cook material model. This model was selected because it can easily include the strain, strain rates and temperature effects. A thermomechanical simulation was built. This weak coupled model is based on the assumption of both the adiabaticity of the problem and a fixed ratio (90%) of the local volume plastic power of the heat sources. The finite element model was restricted to the first impact test. A specific instrumentation of the machine was performed to validate the model. Displacements, linear and angular velocities and impact load were measured. In addition to these local data, kinematics and thermal full field measurements were proposed and provided a rich spatiotemporal database to compare the experimental and numerical results. A qualitative agreement for the strain distribution and an under-estimation of about 20% of the impact load was finally obtained by the model.