Global buckling of composite plates containing rectangular delaminations using exact stiffness analysis and smearing method

• Delaminated plates modelled using a smearing method.
• Solution by exact stiffness method and Wittrick–Williams algorithm.
• Computation time much faster than finite element analysis.
• Accuracy sufficient for preliminary aircraft design studies.

The global buckling of a composite plate with a single rectangular delamination is studied using a smearing method and employing exact stiffness analysis and the Wittrick–Williams algorithm. Computational efficiency is achieved by avoiding discretisation into elements and non-linear analyses, making the method suitable for parametric studies in preliminary aircraft design. Numerical results for longitudinal compressive loading show the level of reduction in buckling load with increasing length and width of delamination. Global buckling strength is increased as the delamination is moved towards the plate surface, but is relatively insensitive to its widthwise and lengthwise location. The results are validated by finite element analysis.