Formation of Tubular Crimp Connections: Elementary Considerations

Laboratory performance tests on aluminum splices for power conductors

“…Since r E % 1 for an aluminum solid conductor attached to an aluminum tubular splice, a crimp connection is achieved in this case only for r Y > 1. In this case, the compressive contact stress increases with increasing r Y , that is, the contact pressure increases with increasing conductor yield strength and thus with increasing conductor hardness [11]. Basically, the above result states that a hard solid conductor can undergo more elastic deformation, and thus store more elastic energy than the barrel before being deformed plastically, if its yield strength is larger than that of the barrel.…”

“…Using a simplified elastic-fully plastic model of a tubular compression connection, Timsit [11] has shown that crimping of a cylindrical solid conductor by a tubular barrel depends crucially on a ratio S YE defined as…”

“…An acceptable compression (i.e., crimp) connection is achieved only if the elastic springback of the conductor (if considered free) is larger than the barrel springback (also if considered free) on release of the mechanical compression load [9][10][11]. Using a simplified elastic-fully plastic model of a tubular compression connection, Timsit [11] has shown that crimping of a cylindrical solid conductor by a tubular barrel depends crucially on a ratio S YE defined as…”

“…Thus, a hard conductor is capable of storing sufficiently more elastic energy than a soft conductor to spring back and generate a compressive contact at the interface with the barrel. It is clear that the results of the analysis in Reference [11] cannot apply directly to stranded conductor compression connections (particularly with uncompacted strands) since interstrand motion will affect conductor springback. Nevertheless, the results suggest that the superior performance of compression splices with hard conductor in the work reported in References [1,2] stems in part from the same effect with stranded conductor where r Y > 1.…”

“…One interesting result of the analysis reported by Timsit [11] relates the magnitude of the residual mechanical stress in a tubular crimp to the barrel thickness. Figure 7 reproduces earlier data [11] and shows the dependence on barrel thickness of the mechanical compression stress in an all-aluminum tubular crimp. The data indicate a monotonic increase in compression stress with increasing barrel thickness.…”