Improved analysis of unidirectional composite delamination specimens

摘要

Generally, the delamination testing of composite specimens involves the analytical determination of the compliance and the energy release rate for the actual configuration. In this work an improved analysis for unidirectional composite delamination specimens is presented, which is based on the results of the last 30 years. The main goal of the present model is the improvement of the global mode decomposition method including four mechanical deformations apart from simple beam theory: Winkler-Pasternak foundation, transverse shear, Saint-Venant effect and crack tip shear deformation, respectively. These effects are investigated separately using a general loading scheme and at the final stage their results are superimposed. The derived model is applied to the mixed-mode Ⅰ/Ⅱ single-cantilever beam, the single-leg bending and the universal mixed-mode bending specimens. Beside the present solution three other ones are adopted to compare the results for the compliance and energy release rate of the mentioned specimens. Although the present model shows similar results to the most accurate finite element model, it is simpler and helps us to understand better the mechanisms of the delamination process.