Fatigue of low-cost carbon fibres

Introduction

Panex/vinylester was selected as 'most-promising' heavy-tow material in the 'Large CFRP Blades' project. Initial testing revealed lower fatigue properties than expected. Four additional material combinations have been tested in a limited test program.

Testing activities

Static compression tests and tension-compression (R=-1) fatigue tests have been accomplished on dogbone shaped and rectangular UD specimens. Although the slopes of the S-N curves of the various material combinations differ considerably, the fatigue strain at 10 million cycles is consistently 0.2%. This relatively low value is acceptable for economic application. Present fatigue results on Panex/epoxy give a much better performance.

Conclusions

The fatigue behaviour of Panex/vinyl-ester material is typical for a group of heavy-tow CFRP materials. Variations of parameters like fibre or resin choice and production technology have limited influence.