A Finite Element Procedure for Analysis of Laminated Composite Plates
Final rept. 1 Jul 1985-30 Jun 1990,
OHIO STATE UNIV RESEARCH FOUNDATION COLUMBUS
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A variational formulation and finite-element implementation of the well-known discrete laminate theory of laminated composite plates is presented. To allow for varying properties of different layers with respect to the fixed reference frame used in the analysis, a linear variation of in-plane displacements over each layer is assumed. The rate of variation can be different for each layer. The coupling between in-plane and transverse deformation is allowed for as is deformation due to shear. The mathematical model essentially assumes the laminated plate to be a stacking of Mindlins orthotropic plates allowing for interfacial continuity of displacement. A finite element scheme implementing the foregoing concepts is described. Through the thickness, nodal points are used to reduce the problem to one of two-dimensional geometry. Three different interpolation schemes viz., the eight-point serendipity, the nine- point Lagrangian and the four-point Lagrangian are used in the isoparametric elements and their effectiveness is compared. The numerical procedure is verified against available solutions and then applied to analysis of stresses in a multi-ply free-edge delamination specimen. The procedure does not satisfy the traction-free edge condition and, therefore, the approach cannot be used to predict delamination and its growth.
- Laminates and Composite Materials
- Numerical Mathematics
- Structural Engineering and Building Technology