Finite Element modelling of thermal deformations in composite aeronautical structures

Abstract

A comparative study of four different finite element (FE) models is presented, to determine the thermal deformations in a typical aeronautical structure. A detailed FE model with solid elements is used as a reference to determine the accuracy given by three FE model with shell elements. The component consists in four planar laminates with (relatively small) curved zones at the joints. The analysis shows that a correct modelling of the curved laminates is needed for obtaining accurate results. If the FE model with shell elements ignores the existence of the curved zones, as is typically done in models used for stress calculations under pressures and loads, unsatisfactory results are obtained. Precision is not significantly increased if the curved zones are modelled in detail and the properties of the shell elements are defined as in the planar zones. For this reason, a technique for modifying the in-plane thermal properties of the elements modelling the curved laminates, that forces them to follow the same shape changes observed in the real curved laminates is presented. The FE model with shell elements obtained with this technique provides the same accuracy than the FE model with solid elements, with a significantly lower computational cost.

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