Z-pin reinforcement in sandwich structures.
In sandwich structures, two layers of composite material are kept at a mutual distance by a lightweight, thick core. To improve the mechanical properties of sandwich structures, carbon pins are inserted in the core material in the z-direction (right through it). The pins prevent cracking (delamination) in the relatively soft core material and realise a more rigid connection between both layers of composite material, which increases the stiffness considerably. This technique is called pin reinforcement, the application of which is becoming more and more widespread.