Influence of Through-Thickness Pinning on Composite Shear Properties

This paper describes results from tests to examine the influence of through-thickness pinning on in-plane shear behaviour, measured by tensile loading of +/- 45A degrees specimens. Samples were produced by both aeronautical and marine manufacturing processes. As few previous studies have investigated pinning of marine composites these were also subjected to out-of-plane shear delamination tests. For both carbon/epoxy laminates the pins reduce the apparent in-plane shear modulus and strength. Pins modify the strain field measured by full-field image analysis, and slow damage development. A new damage mechanism, transverse pin cracking, was observed.