The Strength of Bolted Joints in Multi-Directional CFRP Laminates

Note The series of Current Papers (CP) of the Aeronautical Research Council will shortly be discontinued. The series of Reports and Memoranda (R&M) will continue to be published. Some papers which would otherwise have appeared in the CP Series will be published as R&Ms. SUMMARY Tests have been carried out on simple bolted joints in multi-directional CFRP for a range of laminate configurations and hole sizes. For single-hole joints the various modes of failure have been isolated and the corresponding strengths measured; the effects of variables such as ply orientation, laminate thickness and bolt clamping pressure are discussed in the light of the results. Multi-hole joints have been designed using the single-hole data and test results show that for normal bolt spacings there is little interaction between holes. The results also show that the specific static strengths of these joints can be significantly better than those in conventional materials such as aluminium alloy and steel.