Experimental design of the bearing performances of flax fiber reinforced epoxy composites by a failure map

This paper represents the first effort aimed to the investigation of the pin/hole contact stress and failure mechanisms of epoxy composites reinforced with woven flax fabrics, underwent to tensile bearing tests. In particular, the maximum loads and failure modes are evaluated at varying the laminate geometrical configuration. In order to optimize the use of polymer composites reinforced with flax fibers in structural applications, an experimental failure map, identifying main failure modes of mechanically fastened joints, is obtained as function of hole diameter, distance of the hole from the free edge of the laminate and laminate width. Moreover, a theoretical approach based on the observation that a particular fracture mechanism occurs when its threshold fracture load is lower than the loads of the other competitive ones, is proposed. Main goal of this paper is to give a simple experimental methodology to support the joining design of natural composite laminates reinforced with woven flax fabrics.