Context sensitive design of provincial road Galliera SP4.

In the past centuries and before the invention of automobile, roads consisted mainly of unpaved paths connecting only few cities. Later, in the beginning of the twentieth century, the automobile was introduced and a new type of the transportation system was born. Therefore, it was necessary to change the condition of roads to fit with the automobiles. With the spread and the development of the automobiles, roads also have developed and increased all over the world. That caused negative effects on the environment and humans’ life quality. Thus, highways associations and communities had to take some steps to reduce these effects and care about environmental and cultural issues with the traditional commitment to safety and mobility, and that is known as context sensitive design. The aim of this thesis is to use the concepts of context sensitive design to reduce the negative environmental impacts of provincial road Galliera, which connects via Colombo in city of Bologna to provincial road 3 in Argelato city. Some solutions were proposed in this thesis to reduce traffic noise, fragmentation, fauna mortality and to improve the aesthetics of the road.

Computer aided design and finite element modeling to predict bulk mechanical properties of bone scaffolds using triply periodic minimal surfaces (progettazione assistita al calcolatore ed analisi con il metodo degli elementi finiti per predire il comportamento meccanico di scaffolds ossei creati con l'uso di superfici minime periodiche in tre direzioni)

The aim of Tissue Engineering is to develop biological substitutes that will restore lost morphological and functional features of diseased or damaged portions of organs. Recently computer-aided technology has received considerable attention in the area of tissue engineering and the advance of additive manufacture (AM) techniques has significantly improved control over the pore network architecture of tissue engineering scaffolds. To regenerate tissues more efficiently, an ideal scaffold should have appropriate porosity and pore structure. More sophisticated porous configurations with higher architectures of the pore network and scaffolding structures that mimic the intricate architecture and complexity of native organs and tissues are then required. This study adopts a macro-structural shape design approach to the production of open porous materials (Titanium foams), which utilizes spatial periodicity as a simple way to generate the models. From among various pore architectures which have been studied, this work simulated pore structure by triply-periodic minimal surfaces (TPMS) for the construction of tissue engineering scaffolds. TPMS are shown to be a versatile source of biomorphic scaffold design. A set of tissue scaffolds using the TPMS-based unit cell libraries was designed. TPMS-based Titanium foams were meant to be printed three dimensional with the relative predicted geometry, microstructure and consequently mechanical properties. Trough a finite element analysis (FEA) the mechanical properties of the designed scaffolds were determined in compression and analyzed in terms of their porosity and assemblies of unit cells. The purpose of this work was to investigate the mechanical performance of TPMS models trying to understand the best compromise between mechanical and geometrical requirements of the scaffolds. The intention was to predict the structural modulus in open porous materials via structural design of interconnected three-dimensional lattices, hence optimising geometrical properties. With the aid of FEA results, it is expected that the effective mechanical properties for the TPMS-based scaffold units can be used to design optimized scaffolds for tissue engineering applications. Regardless of the influence of fabrication method, it is desirable to calculate scaffold properties so that the effect of these properties on tissue regeneration may be better understood.

Laser shock peening treatment to control and moderate fatigue crack growth in aircraft structure based on residual stress engineering approach

Laser Shock Peening (LSP) is a surface enhancement treatment which induces a significant layer of beneficial compressive residual stresses of up to several mm underneath the surface of metal components in order to improve the detrimental effects of the crack growth behavior rate in it. The aim of this thesis is to predict the crack growth behavior in metallic specimens with one or more stripes which define the compressive residual stress area induced by the Laser Shock Peening treatment. The process was applied as crack retardation stripes perpendicular to the crack propagation direction with the object of slowing down the crack when approaching the peened stripes. The finite element method has been applied to simulate the redistribution of stresses in a cracked model when it is subjected to a tension load and to a compressive residual stress field, and to evaluate the Stress Intensity Factor (SIF) in this condition. Finally, the Afgrow software is used to predict the crack growth behavior of the component following the Laser Shock Peening treatment and to detect the improvement in the fatigue life comparing it to the baseline specimen. An educational internship at the “Research & Technologies Germany – Hamburg” department of AIRBUS helped to achieve knowledge and experience to write this thesis. The main tasks of the thesis are the following: •To up to date Literature Survey related to “Laser Shock Peening in Metallic Structures” •To validate the FE model developed against experimental measurements at coupon level •To develop design of crack growth slowdown in Centered Cracked Tension specimens based on residual stress engineering approach using laser peened strip transversal to the crack path •To evaluate the Stress Intensity Factor values for Centered Cracked Tension specimens after the Laser Shock Peening treatment via Finite Element Analysis •To predict the crack growth behavior in Centered Cracked Tension specimens using as input the SIF values evaluated with the FE simulations •To validate the results by means of experimental tests

A comparative analysis of seismic design strategies for R.C. frame structures

Negli ultimi anni sono state sviluppate varie soluzioni tecniche per la progettazione sismica di strutture. Questa ricerca sviluppa un metodo di confronto basato sull'analisi di costi di costruzione e danni causati dal sisma. Il metodo viene applicato al caso di studio della scuola di Bisignano (CO, Italia). L'edificio è stato progettato conformemente alle NTC 2008 con approccio tradizionale e combinando il contributo di dissipatori viscosi e dissipazione isteretica. Le strutture vengono poi analizzate sotto diverse condizioni sismiche al fine di calcolare i costi di riparazione attesi e comprendere quale soluzione tecnica risulti più economicamente vantaggiosa a parità di azione sismica di progetto.

Environmental impact assessment of the School of Engineering and Architecture (Lazzaretto) - A pathway towards LEED certification

The current work has for object the improvement and the maintenance of the School of Engineering and Architecture in Via Terracini 28 (Bologna), with the prospective to maximize the operative efficiency reducing to the minimum the environmental impact and the costs. In order to realize this work the LEED certification has been used. LEED (Leadership in Energy and Environmental Design) is a certification system of the buildings. It was born in United States by the U.S. Green Building Council (USGBC)

Design and implementation of the ESEO spacecraft simulator

The thesis work is developed under the European Student Earth Orbiter (ESEO) project supported by the European Space Agency (ESA) in order to help prepare a well-qualified space-engineering workforce for Europe's future. In the following chapters we are going to analyse how to simulate some ESEO subsystem. First of all, the Thermal Subsystem that evaluates the temperature evolution of on-board instruments. For this purpose, simulating also the orbital and attitude dynamics of the spacecraft, it is necessary in order to evaluate external environmental fluxes. The Power Subsystem will be the following step and it models the ability of a spacecraft to produce and store electrical energy. Finally, we will integrate in our software a block capable of simulating the communication link between the satellite and the Ground Station (GS). This last step is designed and validated during the thesis preparation.

Application of the Equivalent Static Analysis method to the design of a steel frame structure with added viscous dampers

All the structures designed by engineers are vulnerable to natural disasters including floods and earthquakes. The energy released during strong ground motions should be dissipated by structural elements. Before 1990’s, this energy was expected to be dissipated through the beams and columns which at the same time were a part of gravity-load-resisting system. However, the main disadvantage of this idea was that gravity-resisting-frame was not repairable. Hence, during 1990’s, the idea of designing passive energy dissipation systems, including dampers, emerged. At the beginning, main problem was lack of guidelines for passive energy dissipation systems. Although till 2000 many guidelines and procedures where published, yet most of them were based on complicated analysis which was not so convenient for engineers and practitioners. In order to solve this problem recently some alternative design methods are proposed including 1. Lopez Garcia (2001) simple procedure for optimal damper configuration in MDOF structures 2. Christopoulos and Filiatrault (2006) trial and error procedure 3. Silvestri et al. (2010) Five-Step Method. 4. Palermo et al. (2015) Direct Five-Step Method. 5. Palermo et al. (2016) Simplified Equivalent Static Analysis (ESA). In this study, effectiveness and differences between last three alternative methods have been evaluated.