ON IMPLEMENTATION OF A NONLINEAR 4 NODE SHELL FINITE-ELEMENT FOR THINMULTILAYERED ELASTIC SHELLS

A simple non-linear stress resultant four node shell finite element is presented. The underlying shell theory is developed from the three di mensional continuum theory via standard assumptions on the displacemen t field. A model for thin shells is obtained by approximating terms de scribing the shell geometry. In this work the rotation of the shell di rector is parameterized by the two Euler angles, although other approa ches can be easily accomodated. A procedure is provided to extend the presented approach by including the through-thickness variable materia l properties. These may include a general non-linear elastic material with varied degree of orthotropy, which is typical for fibre reinforce d composites. Thus a simple and efficient model suitable for analysis of multilayered composite shells is attained. Shell kinematics is cons istently linearized, leading to the Newton-Raphson numerical procedure , which preserves quadratic rate of asymptotic convergence. A range of linear and non-linear tests is provided and compared with available s olutions to illustrate the approach.