A combined analytical and experimental study is conducted to investigate the joint strength and failure behavior in the vicinity of bolt or pin joints in finite composite laminates. The effects of stacking sequence, clamping pressure and fastener stiffness are considered.
One of the major foci of the study is to predict the delamination onset failure strength of joints in finite composite laminates in conjunction with the accurate three-dimensional contact stress analysis via an efficient three-dimensional finite element procedure based on layerwise theory. The three-dimensional contact analysis is composed of a combination of total Lagrangian formulation using the layerwise theory and the Lagrange multiplier technique. The importance of stacking sequence and fastener elasticity for assessment of the localized regions of mechanically fastened joints in composite laminates is quantitatively evaluated in detail. The accuracy and applicability of the proposed procedure are confirmed by comparison to referenced experimental data and computational results from the other previous investigations.
Another major focus of the study is to investigate failure behavior including delamination in the vicinity of bolt and pin joints in finite composite laminates using AE(acoustic emission) test technique. The delamination onset failure strengths of joints in finite composite laminate specimens are measured and the effects of stacking sequence and clamping pressure for the failure behavior of joints in finite composite laminates are investigated and quantitatively evaluated in detail.
The delamination onset failure strengths of joints are predicted using the modified Ye-delamination failure criterion based on the previous layerwise finite element analysis. This prediction is found to be in an good agreement with the results from the experiment using AE technique, and therefore the procedure is confirmed to be an effective methodology for assessing the delamination strengths of mechanically fastened joints in composite laminates.
