Dynamic characterisation and modelling of Electric Cables under representative load conditions

Electric high voltage (HV) cables are commonly used in automotive applications and very prominently in electrified vehicles. These cables are potential flanking transmission paths for structure-borne sound in a broad frequency range and must therefore be included in the NVH design process. Electrical high voltage cables exhibit non-linear mechanical characteristics, when exposed to significant bending the internal geometry of the cable will change and a curvature dependent bending stiffness will result. The electrical cables envisaged in the current publication feature a helically wound stranded aluminium wire core. This conductive core is covered by, in sequence, a silicone rubber insulation, a braided aluminium wire shield with aluminium foil to minimize electromagnetic interference and a silicone rubber outer sheath. An extensive measurement campaign was carried out to dynamically characterize cable specimen of different lengths and cross sections in terms of multi-degree of freedom transfer stiffnesses from 20 to 2000 Hz. In order to investigate possible temperature dependences this dynamic characterisation was carried out for temperatures ranging from -30 until +60 °C. Moreover, additional measurements on bent cable specimen allowed to assess the dependence of the bending stiffness on the cable curvature. It is shown that suitable results can be obtained by modelling the conductive core using an isotropic multi-layer continuum model and by using corrected material characteristics to account for curvature effects. Temperature effects are shown to be negligible within the tested range.