Laminated joints joint efficiencies

It may be noticed that adhesively bonded joints and laminated joints appear to have similar maximum loading densities, i.e. load per unit width, as indicated in Figure 4, while the joint efficiencies of laminated joints are typically higher than those of adhesively bonded joints (Figures 5 to 7). One possible explanation of this behaviour is that in laminated strap joints the bond surface of the strap had a woven roving surface layer, while in adhesively bonded strap joints a laminate having a mat surface layer was used as straps. 

Figure 6 Joint efficiencies of laminated joints with A300 HL adherents.

The effect of the adhesives and resins on the joint efficiency is shown in Figure 9. A possible explanation for the better performance of laminated Joints compared to adhesively bonded joints is the one given above concerning the strap lay-up sequence. However, that does not explain the behaviour of the laminated single-lap joint. 

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