BRIDGING MULTI-SCALE METHOD TO CONSIDER THE EFFECTS OF LOCAL DEFORMATIONS IN THE ANALYSIS OF COMPOSITE THIN-WALLED MEMBERS

Thin-walled member composed of fibre-reinforced polymer composite laminates that have one dimension relatively large in comparison to their cross-sectional dimensions are conventionally modelled by one dimensional beam-type finite elements. Due to the rigid cross section assumption in the formulation of this class of elements, only beam-axis-related deformations can be considered, including flexural, torsional and lateral buckling. However, local deformations such as local buckling of web and flanges, which might have significant effects on the global response of the member, are ignored. In order to model these types of deformations, shell-type elements are used throughout the domain of the member. While the former lacks accuracy in some cases, the latter creates oversized models that are computationally uneconomical. The purpose of the current study is to develop a finite element model to consider the local effects by a multi-scale overlapping decomposition method. In this method, beam-type elements are used as a basis for the whole domain of the member while shell-type elements are placed in critical regions only to incorporate the local effect on the global behaviour. Therefore, it allows considering the local deformations in the numerical analysis without using shell-type elements throughout the domain. Numerical examples are provided in which the results are compared to the full-shell-type model, indicating the efficiency and accuracy of the proposed technique.