Analytical Solution for Flexural Response of Epoxy Resin Materials

A multilinear parametric uniaxial stress strain approach has been used to obtain the closed form nonlinear moment curvature response based on 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 in addition to five non-dimensional tensile and seven non-dimensional compressive parameters. The main parameters are modulus of elasticity and strain at the proportional elastic limit point in tension. Parametric studies show that ultimate tensile stress and compressive yield stress as well as tension and compression flow stresses have the highest effects on flexural load carrying capacity. Moment curvature equations in conjunction with deformation localization and static equilibrium conditions were used to simulate the flexural load deflection response of a beam under three-point bending condition. The simulations reveal that the direct use of uniaxial tensile and compressive stress strain curves underestimates the flexural response due to the differences in the effective volume of the material subjected to critical stresses.