Design,manufacture, mechanical testing and numerical modelling of an asymmetric composite crossbow limb

This paper considers the design, manufacture, mechanical testing and numerical analysis of a crossbow beam (limb). The limb should be lightweight and permit a high deflection of the beam’s tip in order to achieve a good ballistic performance. Consequently, fibre-reinforced polymer matrix composites are suitable candidate materials. However, carbon fibres were considered too brittle for this application. Aramid fibres combine low density and high stiffness but are weak in compression. E-glass fibres are relatively flexible but are of high density. The optimised design developed here uses aramid fibres on the tension face with E-glass fibres on the compression side. This component was manufactured using resin infusion, modelled using a commercial finite element code (Abaqus^®) and the model was validated by mechanical testing. A good correlation was found between the experimentally measured deflections and the numerical results.