Abstract

Abstract

Abstract

The present work presents a preliminary study on the development of a tubular chassis design for automotive industry manufactured with ultraviolet (UV) 3D pultrusion. The use of straight profiles for energy absorption elements and the advantages and feasibility of using curved profiles in other structural areas have been analysed. For the straight profiles, the energy absorption cabability of the material (specific energy absorption, SEA) has been evaluated performing quasi-static compression tests, showing high energy dissipation values, over 50 kJ / kg. On the other hand, the manufacturing of curved profiles by UV pultrusion have been analysed, evaluating the influence of the processing parameters (emitting intensity and pulling speed) and the influence of the reinforcement type on the geometry of the profile. It has been observed that the roving reinforcement allows an easier manipulation and allows to obtain curves without wrinkles with complex sections, due to the free movement between yarns; while the tape reinforcement may present wrinkles during the curving stage. In addition, based on a design with straight profiles, it has been shown that using non-rectilinear profiles, a significant reduction of the necessary connection nodes can be achieved, reducing up to 75% the number of connection nodes based on the analyed design.

Abstract

The catastrophic failure of structures due to the impact of high energy waves or high speed projectiles can occur in a wide range of situations, including ballast impacts on high speed trains, manmade terrorist acts or accidental industrial events. High energy absorbing materials are therefore essential for the protection of both the hardware as well as personnel. One common requirement in all applications is the development of materials with reduced weight whilst guaranteeing high energy absorption levels. The aim of this work has been the investigation of lighter weight metallic composite systems with suitable properties aimed primarily at withstanding high-velocity projectiles and high energy impacts. (E≈ 100 J or v ≈ 120 m/s). Metallic hybrid test panels have been designed and manufactured using both aluminum and aluminum foam layers. To evaluate their efficiency in the case of a high energy impact the panels have been tested under simulated high-velocity projectile impact conditions by means of a pneumatic air cannon.. The tested panels have been assessed using visual inspection as well as X-ray tomography and IR thermography. The panel deformation as well as the delamination between structural layers has been assessed for the different proposed solutions.