BEARING STRENGTH AND DAMAGE PROGRESS FOR PAN-BASED AND PITCH-BASED CARBON-FIBER COMPOSITES

Two bearing strengths are characterized for four PAN-based and four pi tch-based carbon fiber composites of [0-degrees/+/-45-degrees/90-degre es]3S laminate. It is found that full bearing strength is developed wh en the edge distance ratio, e/D, is equal to or greater than 3.0 arid the side distance ratio, w/D, is equal to or greater than 4.0. Bearing strength increases with an increase in die fiber strain to failure, a nd also with the longitudinal compressive strength of the unidirection al composites. No correlation is evident between the tensile strength of fiber and the bearing strengths. The first peak load in the load ve rsus pin displacement curve is recommended for calculating the bearing strength.