Stress analysis of laminated structures from fiber-reinforced composite materials

Kurzfassung

In the open literature a tremendous number of models and procedures for stress analysis of laminated structures is available. With respect to the assumptions across the laminate thickness, theories with Cz1-continuous functions are to be distinguished from layerweise approaches, where for the latter the functional degrees of freedom can be dependent or independent of the number of layers. Transverse shear and normal stresses are more accurate when obtained by locally evaluating the equilibrium conditions. Guide-lines are needed as to which model is suitable for what task. Especially for layerwise models a fair judgment is missing. To ease up this deficiency a number of models are evaluated concerning three different aspects: the accuracy as compared to 3D elasticity results, the effort necessary to reach certain accuracy, and the suitability for developing finite elements. It turns out that the FSDT with improved transverse shear stiffness is the first choice for standard application. At extremely low slenderness ratios or in cases of abrupt changes of load or geometry higher order theories may be useful. However, their field of application is limited; engineering judgment is needed to find out whether full 3D modeling is more appropriate in such cases