Damping properties of non-conductive composite materials for applications in power transmission pylons

This study aims to characterize the fibre direction dependent damping properties of non-conductive composite materials to be used in newly designed electrical power transmission pylons, on which the conducting cables will be directly connected. Thus, the composite structure can be designed both to insulate and to act as a damper to avoid for example conductor line galloping. In order to predict the damping of the composite materials, a comprehensive analysis on a representative unidirectional laminate was carried out. The fibre direction dependent damping analysis of glass and aramid reinforced epoxy and vinylester, partly reinforced with nanoclay or fibre-hybridized, was investigated using a Dynamic Mechanical Thermal Analysis and a Vibrating Beam Testing procedure for five different fibre orientations (0°, 30°, 45°, 60° and 90°). The focus was on damping behaviour evaluation at low temperatures (−20°C and 0°C) and low vibration frequencies (0.5 Hz, 1 Hz and 2 Hz), in order to represent the environmental conditions of vibrating conductor lines during. The prediction of the damping behaviour for coupon-level-specimens with three balanced laminates was successfully carried out with a maximal deviation of maximal 12.1%. </jats:p

Non-linear bending compliance of thin ply composite beams by local compression flange buckling

Passive spanwise bending shape-adaption has the potential to increase the efficiency and manoeuvrability of vehicles with wing-like structures. By utilisation of compression flange buckling, the in-plane stiffness can be tuned to design beams with contrasting pre-buckling and post-buckling bending stiffness. The investigated concept is experimentally validated using a thin-ply laminated composite four-point bending beam, which is designed to experience compression flange buckling in the span with constant moment. The bending stiffness was reduced by more than 41% after the onset of buckling which shows the effectiveness of compression flange buckling for non-linear bending compliance.ISSN:0263-8223ISSN:1879-108