Modeling the stress field in laminated composite plates near discontinuities

A structural model is developed using Reissner's variational principle to analyze stress gradient problems in laminated composite plates. A statically admissible stress field, which has explicit dependence on the thickness coordinate, is selected for each layer. Both interlaminar traction and displacement continuity are enforced between layers. This model is similar to an earlier one developed by Pagano, but has four dependent variables less per layer than Pagano's model. It is shown that the model can duplicate Pagano's results for the same number of subdivisions through the thickness. The uniform axial extension of a [0/90]_s laminate is used as the example problem for comparison to Pagano's theory and to illustrate the methodology.