A SIMPLIFIED IMPROVED BEAM ANALYSIS OF THE DCB SPECIMEN

Large deviations from the simple cantilever beam model have been observed when analysing double cantilever beam tests in composite materials. In the present paper a simplified improved beam model is proposed. The cracked part of the specimen is analysed by means of shear-corrected classical beam theory. The uncracked part is analysed by considering Saint Venant effects and deformation of a beam on an elastic foundation. Superposition of compliances results in a simple closed form expression which can be used to isolate the effects of different material parameters and analytical simplifications. Crack length corrections are discussed as well as the corrections that have to be made when calculating the strain energy release rate. An extensive numerical comparison is made with the more elaborate solutions of Whitney and Williams. Finally, a discussion is made on the relevance of one-dimensional analysis as compared with two- and three-dimensional analyses. The discussion is supported by numerical comparisons.