A ply drop-off element for analysis of tapered laminated composites

A novel ply drop-off element has been developed for the analysis of tapered laminated composites. The element has the capability to accommodate the drop-off within the element. Therefore, drop-off need not lie along the nodal lines. As a result, drop-off location is independent of the mesh division. This facilitates the use of a coarse mesh at the ply drop location even when the stagger distance is very small. This element can be used in the global model without increasing the size of the global structural matrices. The stiffness matrix is developed by superimposing the stiffness matrices of all layers. Since the size of the dropped layer is different from the size of the element a special integration technique has been adopted for developing the stiffness matrices of dropped layers. In addition, a degenerated 1D drop-off element has been discussed. The 1D element can be used when the lateral dimension of the plate is high in comparison to longitudinal dimension. The validation of the proposed drop-off element has been carried out with the help of numerical examples. (C) 1997