Composite materials applied to automotive structures have been developed in the last few years, due mainly to the introduction of new technologies for manufacturing them and the well known advantages of composites versus traditional materials. One of these new processes of manufacturing of textile preforms lead to 3D warp knitted composite sandwich structures.
The application of this process of manufacturing achieves significant reduction of labour and processing cost, in comparison with typical construction of composite parts.
In this paper, this manufacturing process of 3D composite sandwich preforms is described. A tipical composite sandwich structure is composed of skins and core. However, 3D composite sandwich structures are characterised by the existence of transversal fibers which join one skin to the other.
Resultant preforms have the mechanical advantages of classical composite sandwich structures, as a high specific stiffness versus bending. Moreover 3D composite sandwich structures possess high strength versus delamination and peeling due to the transversal fibers. Therefore, these 3D sandwich structures are very interesting for a great number of applications of automotive parts subjected to out and in plane stresses. In the present work, the characteristics of 3D composite sandwich structures for application to automotive parts are described in detail.
Finally, a set of automotive applications of these 3D sandwich structures are shown, ie., a hood, a floor structure and a shock energy absorber. Different experimental tests were carried out in order to obtain the behaviour of 3D composite sandwich structures, at the same time, numerical simulations by means of Finite Element Method were taken into account and correlations were obtained.