Failure of glass/polyester filament wound pipe

Filament wound pipes were fabricated using a terephthalic polyester resin with fibres wound at the ‘ideal angle’, 54°44′. The pipes were tested to failure using closed-end (Mode 2) and unrestrained end (Mode 3) internal pressure tests. The elastic properties and the stress levels associated with different failure processes in the pipe were measured, and found to be consistent with current theories for filament wound angle-ply composites. The failure processes in the two testing modes were significantly different. In Mode 2, resin cracking produced a non-linear stress/strain response and at high pressures the pipes behaved as though complete resin/fibre decoupling had occurred. Final burst in Mode 2 involved large scale fibre fracture whereas in Mode 3 resin shear predominated. The results are discussed in terms of composite theory and failure processes in composite materials.