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Over braiding of superconducting Rutherford cable was used for fibre reinforcement in the composite insulation in this research. Braiding was a suitable alternative to fabric tape winding for achieving ultrathin insulation with required electrical breakdown voltage. A brief overview of the superconducting magnets, their application and requirements of insulation has been covered in order to bridge the literature gap between braiding and the superconducting magnet field of studies. Organic size coating on the fibre leaves carbon residue during high temperature treatment of the cables and hence glass fibre was desized before braiding. Braiding difficulties with desized glass fibre and possibility of braiding using compatible size coating has been discussed. The requirement of ultrathin braided layer was achieved with sufficient surface coverage with a suitable braid angle and fibre. As part of the study braid cover factor variation on the surface of the cable was investigated and it was discussed using image analysis.

This paper presents the tensile response of thin-walled composite tubes with multi-axial fibre architecture. A hybrid braid-wound layup has the potential to optimise the composite tube properties, however, stacking sequence plays a role in the failure mechanism. A braid-winding method has been used to produce stacked overwound braid layup [(±45°/0°) 5 /90°4] T. Influence of stacking sequence on premature failure of hoop layers has been reported. Under tensile loading, a cross-ply composite tube with the alternate stacking of hoop and axial fibre show hoop plies splitting similar to the overwound braided composite tube. However, splitting has been restricted by the surrounding axial plies and contained between the adjacent axial fibre tows. This observation suggests hoop layers sandwiched between braid layers will improve structural integrity. A near net shape architecture with three fibre orientation in a triaxial braid will provide additional support to prevent extensive damage for plies loaded in off-axis. Several notable observations for relatively open braid structures such as tow scissoring, high Poisson's ratio and influence of axial tow crimp on the strain to failure have been reported. Digital Image Correlation (DIC) in conjunction with surface strain gauging has been employed to capture the strain pattern.

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