Abstract

This work summarizes the recent developments of a numerical framework to predict the mechanical behaviour of thermoplastic composites. It supports the design of a next generation thermoplastic multi-functional fuselage which uses advanced joining techniques such as thermoplastic welding to reduce both weight and cost by limiting the amount of mechanical fasteners required. At the lower end of the testing pyramid the framework is able to accurately predict typical preliminary design allowables such as laminate, open-hole and welded joints strength through a high-fidelity modelling approach. This information is then passed on to the structural level in a validated building-block approach to efficiently virtual test the compression strength of fuselage panels during post-buckling while also taking into account the influence of damages at the skin-stiffener interface.

Abstract

Abstract

Metamaterials research and, moreover, their obtaining by additive manufacturing is trendy because of their potential industrial applications, since lattice structures can save weight when integrated in larger parts. For this reason, it is important to draw these new material properties in order to compare them with traditional structures obtained by classic manufacturing methods. In this work we present a numerical procedure to determine the mechanical properties of a metamaterial based on periodic cells. To date, for these materials there are no standard procedures to test and validate their structural properties, and specifically to determine their mechanical bending behaviour. We apply a virtual testing procedure using finite elements to determine the homogeneous elastic modulus, Young's modulus and shear modulus, using a set of modified bending virtual test, based on the three point bending and the four point bending test [1]. Theses physical testing procedures are common in sandwich composite materials [2], and can be apply to metamaterial testing taking into account some geometrical and material aspects to determine the proper parameters for testing. The results obtained are macroscopically independent on the number of elemental cells used in the metamaterial, and permit us to consider the intrinsic defects that may appear in the 3D additive manufacturing materials.