Analytical Solution for Flexural Response of Epoxy Resin Materials

Abstract

A piecewise linear parametric uniaxial stress-strain approach has been used to obtain the closed form nonlinear moment curvature response on the basis of strain compatibility in bending for epoxy resin materials. The stress-strain curves, consisting of a bilinear ascending curve followed by strain softening and constant plastic flow in tension and compression, are described by two main parameters, with an additional five nondimensional tensile and seven nondimensional compressive parameters. The main parameters are the modulus of elasticity and strain at the proportional elastic limit point in tension. Parametric studies show that ultimate tensile stress and compressive yield stresses and tension and compression flow stresses have the highest effects on flexural load carrying capacity. Moment curvature equations, in conjunction with softening localization and static equilibrium conditions, were used to simulate the flexural load-deflection response of a beam under three-point bending (3PB) conditions. The simulations and experiments reveal that the direct use of uniaxial tensile and compressive stress-strain curves underestimates the flexural response caused by the stress gradient and the differences in the effective volume of the body subjected to critical stresses.