Filament winding of composite tubes

Composite tubes outperform traditional pipe materials in applications requiring low weight, corrosion resistance and high strength. However, the lack of simple and reliable end fittings have limited their use. A new end fitting design for composite tubes have been designed, produced and tested. The end fitting consist of two main parts, a bolted connection with radially placed bolts and a custom made composite tube. The tube is reinforced in the ends with fiber mats to achieve a layup suitable for a bolted connection. In addition a production method involving filament winding and fiber mats has successfully been developed. Two tests of the produced tube were performed: an internal pressure test and a tensile test. During the pressure test, the tube leaked at a low pressure and the quality of the end fitting could not be determined. Axial strength was tested with a tensile test and a very good result was obtained. The linear load limit was found to be 67,2 kN and the maximum axial load was 96,2 kN. This is in good agreement with the predictions. It was concluded that this new end fitting design is a promising solution for composite tube junctions