The initial contact stress in aluminum compression connections with high temperature low sag conductors

Abstract:
In aluminum compression connections with high temperature low sag conductors the applied mechanical stress at the assembly determines the degree of metal forming of the connector and the conductor. Furthermore, the size of the formed conducting contact area and hence the quality of connections depend on the applied mechanical stress. The residual stress in the contact interface is established due to the elastic spring-back of the conductor and the connector after the release of the compression tool. Thereby, the extent of initial contact stress is influenced by several design factors of the compression connection such as materials and geometry of conductor, connector and compression tools. The initial contact stress decreases dependent on time and connection temperature. In order to clarify whether stress relaxation and creep could be a relevant ageing mechanism in compression connections with high temperature low sag conductors, the initial contact stress must be known at first. For this purpose, the metal forming of stranded conductor and connector resulting from the assembly is calculated by a FEM analysis. The initial stresses in the contact interfaces are investigated as a function of different design parameters.