This work investigates the application of variable-density polymeric foams for energy absorption. The study is based on the possibility, developed within a PRIN research project, of controlling the density of a porous component with high flexibility through additive manufacturing technologies: a printing head equipped with a microfluidic nozzle deposits a biphasic “ink” consisting of a...
Contesto I laminati in lega leggera d’alluminio, come ad esempio quelli appartenenti alla serie 6000, mostrano una pronunciata anisotropia in direzione planare e normale, derivante dal processo di laminazione. Sebbene questo comportamento sia stato ampiamente investigato in condizioni di carico quasi-statico, risultano ancora limitate le informazioni riguardanti una possibile influenza dello...
Il lavoro presenta uno studio sperimentale e numerico del comportamento visco-plastico e dell’evoluzione del danneggiamento duttile della zona termicamente alterata (Heat-Affected Zone, HAZ) in lamiere di lega di alluminio AA6005-T6, utilizzate in applicazioni di crash ferroviario, con particolare riferimento alla deformazione a rottura (failure strain) e alla sua dipendenza dallo stato...
Periodic truss lattices are increasingly considered for lightweight impact-mitigation applications because their macroscopic mechanical response can be tailored through a limited set of geometric parameters. However, their practical design presents two main issues: the computational cost required to generate large and consistent simulation datasets, and the difficulty of solving the inverse...
Abstract
The polycarbonate exhibits a very special deformation mode in tensile tests, as the plastic strain firstly flows uniformly, then localizes at a neck section, then propagates all along the specimen until the necking vanishes, and finally flows again uniformly until failure.
This feature poses significant challenges in the characterization of the hardening of polycarbonate, as...
Long-rod kinetic penetrators, composed of high density materials such as tungsten heavy alloys (WHA), are designed to deliver large amounts of kinetic energy to an extremely concentrated area of the target, traveling at velocities exceeding 1000 m/s. Advanced multilayer protections with bulging effect are designed to counter this threat, disrupting the projectile by deforming in two opposite...
The inverse Finite Element Method (iFEM) is a robust and efficient technique for reconstructing full-field displacements from sparse strain measurements, requiring only structural geometry, boundary conditions, and sensor data—without relying on material properties or external load information. This load-independence makes iFEM attractive for Structural Health Monitoring (SHM) and Digital Twin...
Blast loading represents a challenging scenario for numerical modelling, as it involves highly non-linear, high-intensity and short-duration events, typically at scales that are too small to resolve with practical numerical discretization and further complicated by material behaviour and strain-rate effects. Even for relatively simple structural configurations, obtaining consistent agreement...
The strain rate- and stress state-dependent fracture behavior of high-strength AA6005-T6 aluminum sheet is characterized experimentally and numerically. Tests employed shear, hole tension, and notch tension specimens across strain rates of 10−310−3 to 500 s−1500 s−1. Positive strain rate sensitivity emerged in axial force responses for hole and notch tension specimens, with fracture limits...
The increasing demand for lightweight structures across various engineering sectors has driven a significant surge in the use of composite materials. However, predicting the behaviour of these materials under extreme conditions remains a critical challenge. Composite materials are inherently difficult to model due to their anisotropic behaviour, layered architecture, and complex damage...
Le esplosioni sottomarine (UNDEX, Underwater Explosions) rappresentano uno dei fenomeni fisici più complessi e allo stesso tempo rilevanti per l’ingegneria navale, offshore, civile e militare. Esse producono effetti dinamici che differiscono in modo sostanziale dalle esplosioni atmosferiche a causa delle proprietà fisiche dell’acqua, che presenta elevata densità e scarsa comprimibilità. Queste...
Il presente lavoro analizza in dettaglio il comportamento meccanico di una ghisa sferoidale, materiale di crescente interesse grazie ai numerosi vantaggi rispetto alle ghise tradizionali e alla limitata disponibilità in letteratura di dati relativi al suo comportamento ad elevate velocità di deformazione, in particolare in condizioni di carico non uniassiali.
La caratterizzazione sperimentale...
Lattice metamaterials are widely investigated as efficient lightweight energy-absorbing structures because their mechanical response can be tailored through geometry. Among them, out-of-plane extruded hexagonal lattices represent the bechmark configuration against which novel architectures for progressive collapse under compressive loading are evaluated. Most studies focus on periodic or...
L’obiettivo del seguente lavoro è quello di investigare sperimentalmente l’influenza della temperatura nello sviluppo dei meccanismi di danneggiamento del rame OFHC ad alte pressioni e velocità di deformazione. A tal fine, sono stati condotte prove di impatto simmetrico Rod-on-Rod (RoR) tramite un cannone a gas leggero a singolo stadio per diverse velocità e temperature controllate. Durante il...
Energetic materials are substances that undergo rapid chemical reactions when subjected to an appropriate stimulus, releasing substantial amounts of energy, heat, and gas. This class of materials finds various applications, including pyrotechnics, explosives, and rocket propellants. Energetics are intrinsically linked to shock wave propagation phenomena: while their chemical reaction often...
I serbatoi flessibili aeronautici richiedono elevata crashworthiness per prevenire perdite di carburante in caso di impatto. I materiali tradizionali, pur offrendo elevati carichi di rottura, presentano una ridotta deformabilità. Questo lavoro presenta lo sviluppo e la validazione sperimentale di una nuova generazione di tessuti gommati innovativi, funzionalizzati per massimizzare l'energia...
