A mixed-enhanced finite-element for the analysis of laminated composite plates

This paper presents a new 4-node finite-element for the analysis of laminat ed composite plates. The element is based on a first-order shear deformatio n theory and is obtained through a mixed-enhanced approach. In fact, the ad opted variational formulation includes as variables the transverse shear as well as enhanced incompatible modes introduced to improve the in-plane def ormation. The problem is then discretized using bubble functions for the ro tational degrees of freedom and functions linking the transverse displaceme nt to the rotations. The proposed element is locking free, it does not have zero energy modes and provides accurate in-plane/out-of-plane deformations . Furthermore, a procedure for the computation of the through-the-thickness shear stresses is discussed, together with an iterative algorithm for the evaluation of the shear correction factors. Several applications are invest igated to assess the features and the performances of the proposed element. Results are compared with analytical solutions and with other finite-eleme nt solutions. Copyright (C) 1999 John Wiley & Sons, Ltd.