Local Metal Hybridization of Composite Bolted Joints

Composite technologies have been proven to be advantageous in allowing for the development of aircraft and spacecraft structures which feature highly integral design concepts. However, structural joining using conventional mechanical fastening techniques still remains an indispensable issue within the design of advanced composite structures. Crucial challenges facing structural joining are the inherent complexity of the stress state at the bolt locations on the one hand and the multifaceted fracture mechanics of composite material on the other. The aerospace industry’s increasing requirement for weight reductions and a more efficient use of composites demands not only an accurate understanding of this material’s mechanics and its damage behavior at composite joints but the development of advanced joining techniques as well in order to be able to fully exploit the outstanding capabilities of composite material. The use of a local hybridization with metal represents a suitable and technologically feasible means to increase the mechanical efficiency of highly loaded composite bolted joints which allows for a significant improvement of the overall structural efficiency of real composite structures. This chapter presents the hybrid reinforcement concept and addresses some fundamental topics of this technology’s mechanical behavior.