Predictive modeling of rubber-oil toughened epoxy resin using FEM

Abstract

In the present investigation, an Epoxy Resin (ER) was first modified by varying concentrations of a novel liquid Rubber-Oil (RO). RO modified epoxy (ROE) was cast into dogbone shaped samples and tensile test was conducted on them. The RO Es were machined to Three -Point Bending (3PB) specimens and subjected to fracture toughness test. Fractured surfaces subjected to Field Emission Scanning Electron Microscopy (FESEM) exhibited biphasic morphology with phase-separated RO particles distributed in epoxy domain. Predictive modeling of the RO Es was then carried out through FEM by considering a Representative Volume Element (RVE) assuming Body-Centered Cubic (BCC) distribution of RO particles in epoxy domain. Effect of rubber-oil volume fraction (RO VF) on effective properties of RO Es was studied through a novel elastic stiffness tensor based homogenization scheme coupled with the FE model. Results show that, the effective Young’s and shear moduli decrease with ROVF with subsequent increase in bulk modulus and Poisson’s ratio. When subjected to stress analysis, the FE model revealed that high triaxiality associated with crack tip favours the cavitation of RO particles. Both the von-Mises as well as the hydrostatic stresses were observed to be unique functions of RO particle bulk modulus. The predicted values of Young’s modulus as a function of RO VF were observed to be in good agreement with experimentally obtained values.