Safety of aircraft structures in the context of composite element connection

Abstract

– Recently, there has been a growing trend towards an ever greater use of composite materials in aircraft structures. This necessitates a search for effective ways of joining these materials. The desirable characteristics of such joints are predominantly high strength and low mass, both of which are features offered by rivet nuts. The study was conducted on one type of glass fabric material, from which two types of composite specimens were prepared. Each specimen used the same type of fibre of the same number of 3 layers, yet of different lay-up. Specimens were joined with aluminium alloy and steel rivet nuts to produce single and multi-row parallel models of riveted joints for further testing and analysis. The specimens were clamped in the grips of tensile machine and subjected to a tensile strength test. In the work, the course of the forces in the rivet nuts joint and the failure modes and effects of joint failure were analysed. The distribution of vertical displacement was examined according to the joint material and two fibre orientation variants. To determine the distribution of displacements, the FE (Finite Element) method was used. Upon completion of the experimental stage, the obtained results were subjected to comparative analysis.