Pin and bolt bearing strength of fibreglass/aluminium laminates

Under bolt-bearing conditions, the features of the load-displacement curve allowed for the individuation of two bearing strengths, labelled as 'damage-bearing strength' and 'failure-bearing strength', respectively. The damage-bearing strength was substantially unaffected by the bolt torque, and was up to 20% higher than the pin-bearing strength. The failure-bearing strength slightly increased with increasing the clamping pressure, achieving values up to 85% larger than the pin-bearing strength. From the microscopic failure modes observed, a possible explanation for the two bolt-bearing strengths recorded was given.