Experiments have been carried out to quantify theeffects of rubber content and strain rate on the elastic and plasticdeformation behaviour of core-shell rubber-modified epoxies.Both the Young's modulus and the yield stress were found to beslightly dependent on strain rate, but very sensitive to the volumefraction of rubber particles. Finite element analyses have also beenperformed to determine the influences of rubber content on thebulk elasticity modulus and the yield stress. By comparing withexperimental results, it is found that the Young's modulus ofrubber-toughened epoxies can be accurately estimated using theMori-Tanaka method, provided that the volume fraction of rubberparticles is appropriately evaluated. A yield function is proposed toquantify the effects of hydrostatic stress on the plastic yieldingbehaviour of rubber-modified epoxies. Agreement withexperimental results is good. Also, a viscoplastic model isdeveloped to simulate the strain-rate-dependent stress-strain relations.
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