Revisiting the micro-buckling of carbon fibers in elastic memory composite plates under pure bending

Abstract

Elastic memory composites (EMCs) consisting of carbon fibers embedded in a shape memory polymer (SMP) matrix are receiving substantial interests in deployable space structures. Their favourable ability to be packaged to a much high folding curvature is due to that the soft SMP matrix allows the fibers to micro-buckle without breaking. This paper studies the buckling mechanics of fibers embedded in a thin EMC plate at finite strain under pure bending. The analytical expressions of three key parameters, namely the locations of neutral strain surface and critical buckling surface, the half-wavelength of buckling fibers, are determined by energy method. The fiber is modeled as 3D linear elastic solid, and its size effect on the shear strain of matrix is considered. Detailed discussions and comparisons are provided between the results obtained from this work and the ones without considering the fiber size effect. It is shown that considering the size effect of fibers has an influence on the half-wavelength and could reasonably predict the scope of the model, but it produces little differences on the variation trend of locations of neutral strain surface and critical buckling surface.