Nonlinear bending behavior of unidirectional EMC laminates

A study was performed on the nonlinear bending behavior of unidirectional fiber-reinforced elastic memory composite (EMC) laminates above the glass transition temperature of its resin (T_g). A series of multi-constraint bending experiments about EMC laminates were firstly introduced. According to the experimental results, the shape function of microbuckled fibers was proposed. Different strain energies of EMC laminate under bending were then analyzed. Finally, the bending moment as functions of curvature and equivalent bending strain was deduced based on the principl of virtual work. The results show that the neutral strain surface of EMC laminates rapidly approaches the outer surface during the bending process. The neutral strain surface location and bending behaviour of EMC laminates are very sensitive to the in-plane shear modulus. At the initial stage, the traditional linear elastic plate theory can describe the deformation response. However, with further increase of the bending curvature, the nonlinear model presented in this study must be considered. The theoretical predictions are agreeable with experimental results of EMC laminates under four-point pure bending.