Development and optimization of the structure of a commercial vehicle for last mile deliveries

Nowadays, the automotive sector is going through a phase of continuous evolution, driven by technological innovation and new requirements for sustainable mobility. In this context, the issue of door-to-door delivery management is assuming an increasingly important role, due to the expansion of e-commerce. This thesis work is part of a project in collaboration with a major car manufacturer, which aims to develop a last-mile delivery vehicle with a modern and sustainable design. The commercial vehicle in question will feature an innovative, modular structure and an optimized arrangement of packages inside it. The vehicle will be powered by a battery propulsion system and could feature autonomous driving technology, to improve the efficiency and sustainability of delivery operations. The central point of the research activity developed in this thesis is the structure of the commercial vehicle. The topics covered are the development, the analysis and the optimization of the structure. It has been designed with the goal of achieving the best possible efficiency not only in terms of weight and cost, but also in terms of occupant protection and cargo safety. Following trends in the automotive industry in recent years, the structure considered has been made for a battery electric vehicle and in the continuation of this thesis work an increasingly widespread material for vehicle structures has been used, namely a specific aluminium alloy, which is not the only possible option for creating the vehicle structure. The advantages of this material will be highlighted in the simulations carried out, such as light weight, high mechanical strength and good energy absorption capacity due to its ductility. The research presented in this thesis aims to develop a vehicle chassis optimized not only in terms of materials, using a high-performance aluminium alloy, but also through an accurate design of the beam sections, to obtain the right compromise between weight and structural stiffness. After this initial optimization process, the structure has been defined in more detail at CAD level and consequently a non-linear FEM model of the vehicle structure has been created to perform impact analyses, in compliance with commercial vehicle regulations. Furthermore, specifically to perform impact analyses, research has been conducted to evaluate the use of an innovative material for the design of a cutting-edge frontal structure for vehicle safety. The material in question is the aluminium foam, which is an emerging material used in various fields, including the automotive industry, thanks to its outstanding properties, that are energy absorption, lightness, acoustic and thermal insulation. The research has led to obtaining a model to represent the aluminium foam, and more generally the entire front part of the vehicle, which will then be inserted into the complete vehicle structure.