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 pitch-based carbon fiber composites of [0-degrees/+/-45-degrees/90-degrees]3S laminate. It is found that full bearing strength is developed when the edge distance ratio, e/D, is equal to or greater than 3.0 and 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, and also with the longitudinal compressive strength of the unidirectional composites. No correlation is evident between the tensile strength of fiber and the bearing strengths. The first peak load in the load versus pin displacement curve is recommended for calculating the bearing strength.