Construction of 3-D realistic representative volume element failure prediction model of high density rigid polyurethane foam treated under complex thermal-vibration conditions

Abstract

The mechanical failure behaviors prediction model of rigid polyurethane foam (RPUF) treated under complex thermal-vibration conditions was constructed by experiment of tensile properties and numerical simulation for the further analysis of the failure progress and mechanism of RPUF. On the basis of scanning electron microscope (SEM) observation, a realistic representative volume element (RVE) of RPUF was firstly established by means of Voronoi-spherical tessellations. Tensile properties of RPUF treated under different thermal-vibration conditions were measured subsequently. Results of the tensile properties characterization of RPUF suggested that the thermal and vibration treatment on RPUF reduced its tensile strength and fracture elongation decrease due to the chemical degradation of polyurethane (PU) matrix and physical breaking of the foam structure. The tensile constitutive relationship derived from the tensile experiments was assigned to the realistic RVE, and the thermal-vibration failure prediction model of RPUF was further constructed in the ABAQUS software. The numerical simulation results revealed that the stress concentrations appeared and extended along with the weakness regions of RPUF structure under the external load. The stress-strain curves of thermal-vibration treated RPUF obtained from the prediction model were in well agreement with the experimental results, and the average computation error was less than 3%. It indicated that the prediction model can accurately describe the failure progress of thermal-vibration treated RPUF. This work provides ideas for the design of the foam materials with high thermal-vibration aging resistance by numerical simulation in the future.