bluuebunny/crossref_metadata_2025_split huggingface dataset:
Micro-scale modeling of Lithium-ion battery
Authors: Clerici D , Mocera F 
Published: March 2021

Abstract
Good energy density, long lifetime, high capacity and high voltage make Lithium-ion batteries the most widespread energy storage systems, suitable for several fields of application. Nevertheless, usage leads to cell degradation which mainly results in capacity and power fade. Degradation phenomena are the result of the interaction between mechanical and electro-chemical mechanisms, which are reviewed in this paper. Lithium-ion batteries store and deliver electric energy by means of ions transport between anode and cathode through the electrolyte. The active material of the electrodes consists of micrometer particles which can host lithium ions through insertion/extraction processes. These processes are modelled as diffusion-mechanical problem, since the lithium concentration gradient within the particle due to ions diffusion generates internal stresses in analogy with a temperature gradient. The model in this work, usually referred as diffusion induced stress (DIS), can predict the stresses in the active material particles which are the driving force for damage, pulverization, exfoliation and crack propagation. Indeed, the damage induced by the insertion/extraction processes explains the capacity reduction over charge/discharge cycles: a critical issue for batteries lifetime.
The future of the Autonomous Emergency Braking for Powered-Two-Wheelers: field testing end-users’ acceptability in realistic riding manoeuvres
Authors: Marra M , Lucci C , Huertas-Leyva P , Baldanzini N , Pierini M , Savino G 
Published: March 2021

Abstract
Motorcycle Autonomous Emergency Braking system (MAEB), is a technology that introduces also on Powered-Two-Wheelers (PTWs) the autonomous braking, which is able to apply autonomously a braking force to reduce impact speed in emergency situations. This system was shown to be possibly effective in reducing numbers of deaths and serious injuries resulting from motorcycle crashes. However, its safe applicability on standard vehicles and the acceptability among end-users has still to be proven. The goal of the study presented in this paper is to assess the acceptability and the controllability of automatic braking events deployed in realistic riding manoeuvres. Field tests were conducted involving 55 common riders as participants on three test vehicles: a naked motorcycle, a sport touring motorcycle and three-wheels scooter. The automatic braking was tested in four riding manoeuvres (straight-lane, lane-change, slalom, and curve) deployed remotely by an investigator at a travelling speed of 35-50 km/h. The system was tested with the higher levels of interventions tested so far by common users and more than 1100 interventions were recorded. The results of this study will allow having a new understanding on the limits of MAEB system.
Analysis of the resistance of adhesively bonded joints with rigid-flexible substrates
Authors: Dicosta F , Morano C , Alfano M , Furgiuele F 
Published: March 2021

Abstract
Hydrogen, as an energy source, appears as a valid alternative to traditional fossil resources and supports the required reduction of CO2 emissions. The most recent hyperbaric tanks built for hydrogen storage (type IV) are made of composite material. For the manufacturing of these tanks, an adhesive layer is being used to join the flexible internal polymeric core, the liner, with the external composite shell. This work aims to study the strength of the liner-composite joint using the Floating Roller Peel (FRP) test. To this purpose, finite element analyses of the peeling process are carried out using the cohesive model. In order to establish a framework for the investigation of the joint properties as a function of manufacturing parameters (e.g., adhesive type and surface preparation), this paper describes a potential procedure that can be used for the identification of joint properties.
Functional safety and reliability for innovative vehicle braking system and integration with electric traction units
Authors: Favilli T. , Delogu M. , Pugi L. , Berzi L. 
Published: March 2021

Abstract
Newly electric vehicle architectures require intensive virtual and physical testing for safety assessment, due to the increasing relevance of By-Wire systems and the presence of innovative control algorithms for ordinary driving scenario, potential emergency situations or Advanced Driver-Assistance Systems implementation purpose. To reduce the development time while increasing system reliability and the a priori knowledge about its safety requirements, the evaluation of such aspects should be performed. In accordance to ISO26262 standard, authors propose a systematic approach based on Virtual FMEA, in order to assess the functional safety level of hybrid brake plant. Plant modification and securing strategy as been presented and implemented in target vehicle model, evaluating their performances in simulation environments, in order to met required Automotive Safety Integrity Level. This work is developed in the ambit of OBELICS European Project.
Single-lap joints of similar and dissimilar adherends bonded with a polyurethane adhesive used in the automotive industry
Authors: Ciardiello R , Boursier Niutta C , Di Sciullo F , Goglio L 
Published: March 2021

Abstract
The mechanical performances of single-lap joints between similar and dissimilar adherends bonded with a bi-component polyurethane adhesive have been studied in the present work. The substrate materials include both carbon fibre reinforced composite material (CRFP) and painted metal substrates (PMS). The following substrate combinations were tested: CFRP/CFRP, PMS/PMS, and CFRP/PMS. Two adhesive overlaps, 12 mm and 24 mm, with a fixed thickness were studied to assess the mechanical behaviour of the adhesive joints. The experimental results have been used to construct a finite element model of the single lap joint tests. The objective is to determine the material cohesive properties, in particular the maximum shear stress and the corresponding energy release rate, of the adhesive layer for each retained combination of substrates. An optimization scheme based on transient nonlinear finite element analysis has been here considered, where cohesive parameters of the adhesive layer are handled as design variables. Material parameters are firstly identified for the 12 mm overlap, minimizing the discrepancy between the experimental and numerical force-displacement curves. Then, to validate the obtained properties, results of the 24 mm overlap single lap joint tests are used. The comparison between the experimental and numerical results shows a very good agreement.
Design of a non-destructive test for validating models of hydrogen migration
Authors: Beghini M , Bertini L , Macoretta G , Monelli B D , Valentini R 
Published: March 2021

Abstract
High-strength steels, despite their excellent mechanical properties in normal conditions, can be susceptible to hydrogen embrittlement. Due to the service loads or residual stresses, hydrogen migrates within the component and accumulates in the regions where the highest tensile hydrostatic stress occurs. As a consequence, component brittle failure can occur even if the initial or mean hydrogen concentration is lower than the critical value. The availability of models predicting the hydrogen diffusion within the component is a crucial task for the design. Several diffusive models have been presented in the literature and some general-purpose finite element codes have already implemented some of them. However, the validation of those models is still an open issue due to the difficulty in performing accurate local measurements of the hydrogen concentration. This study deals with the design of a test potentially able to validate hydrogen migration models. In the test, a four-point bending configuration is applied to a properly shaped hourglass specimen, previously charged with hydrogen, extracted from thin high-strength steel sheets. The specimen geometry and the loading configuration were designed to obtain a central region in which the stress and strain field is uniform in plane and exhibits a quasi-uniform gradient in the thickness direction. As a consequence, it is expected a large enough central region of the specimen in which the Hydrogen can migrate only in the thickness direction during the typical duration of the test. The local hydrogen concentration is evaluated by measuring the flux leaving the tensile surface of the specimen by a solid-state hydrogen sensor.
Development of a wearable device for the early diagnosis of neurodegenerative diseases
Authors: Avalle M , Belotti V , Frascio M , Razzoli R 
Published: March 2021

Abstract
The progressive evolution of information and sensing technologies is giving pulse to the development of wearable mobile devices in search of life quality improvement. A relevant field of application is healthcare, with the development of wireless unobtrusive wearable solutions for the continuous remote health monitoring of patients. These wearable devices are particularly important for neurodegenerative diseases due to the possibility of early stage diagnoses through continuous monitoring to collect earlier significant data. Discovering specific symptoms and early defining medical treatments can delay, if not stop, the pathology progress whereas, once major symptoms like restricted or impaired mobility has appeared, the patients already underwent relevant and irreversible brain damage. The aim of this work is to show the development of the Neuroglass, a wearable smart glasses device for early stage diagnosis and monitoring of Parkinsonian-type neurodegenerative diseases. The designed frame is compliant to the standards and in order to embed the sensors to collect data from head and eyes movements since one of the early symptoms of Parkinson’s disease has proven to be eye tremors. Preliminary laboratory tests, e.g. head accelerations measurements for different body movements, were carried out in order to choose properly the characteristics and positioning of the sensors; afterwards the device’s frame was designed by means of a 3D parametric CAD and built by additive manufacturing. The design was validated by first experimental test on monitoring eye movements and blinks.
A statistical study on long freight trains equipped with radio communication within Shift2Rail
Authors: Cantone L , Laghi D , La Rovere S 
Published: March 2021

Abstract
Paper reports the main results of a systematic study on longitudinal train dynamics (LTD) of long freight trains equipped with radio communication. It is divided in two parts: the first addresses the global sensitivity analysis aiming to find the most relevant parameters that, with their associated uncertainty, mainly affect the LTD of coupled trains, independently by the train length or train operation. The second part studies the LTD of classic freight trains in Germany (i.e. with one Traction Unit -TU- at the beginning of the train), considering the variation of the parameters identified during the sensitivity analysis. Finally, several train-consists with two up to four TU and having train length up to 1500 m are found to be as safe as the classic trains and therefore can put in service, as long as the LTD is concerned, allowing a relevant increase of efficiency.
Friction dissipation in reciprocating internal combustion engines: cam tappet contact
Authors: Sansone P , Lavella M 
Published: March 2021

Abstract
The interest towards fuel consumption reduction in reciprocating internal combustion engines has achieved a key role starting from the first energy crisis during the 70’s. Even if in alternate phases, such interest had further increased during the following years assuming a fundamental role in the last years. The reason lies in the introduction of regulations that limit the emissions of carbon dioxide, as it belongs to the family of greenhouse gasses. A reduction of the friction dissipation reflects directly on consumption reduction and consequently in an improvement of emissions. The main goal of this research is to model the friction dissipation at the cam tappet interface. In this research an analytic model is proposed, it allows to estimate the dissipation due to friction with a complexity appropriate to that of the design phase and which allows to select between different design solutions in order to optimize the efficiency of the cam tappet interfaces. Model results are coherent with experimental results reported in literature.
Multiscale three-dimensional stress analysis of voids clusters for the modelling of degenerated graphite in cast iron
Authors: Rizzoni R , Livieri P , Tovo R 
Published: March 2021

Abstract
We propose a multiscale three-dimensional model for the stress analysis of a cluster of degenerated graphite in spheroidal cast iron. The model allows to study the effect of graphite microstructure on the average stress distribution inside the cluster. At the microscale, precipitates of degenerated graphite are modelled as spheroidal voids. At the mesoscale, clusters of degenerated graphite are viewed as spheroidal inclusions made of equivalent porous elastic material. The equivalent elastic properties of the porous material are calculated using an approach proposed by Tandon and Weng and based on Eshelby’s equivalent principle and the Mori-Tanaka’s estimate. FE simulations at the microscale and at the mesoscale are performed in order to numerically validate the multiscale model.
Fatigue crack-growth predictions for a railway axle under material data variability
Authors: Giannella V 
Published: March 2021

Abstract
This document reports a probabilistic approach for residual fatigue life predictions of a cracked railway axle with allowance for variability of the input data. A NASGRO formulation was used for such a purpose, with its main parameters considered as uncorrelated random variables varying in given ranges. A load spectrum was considered in order to take into account of the actual loading conditions that these components undergo. The presented approach aimed to perform residual fatigue life predictions in terms of both mean value and dispersion around it. The results were also used to drive deterministic approaches in calculating conservative crack-growth assessments.
Influence of coil contact on static behavior of helical compression springs
Authors: De Crescenzo F , Salvini P 
Published: March 2021

Abstract
Large deformations of helical springs are affected by coil contact, but most available spring modelling techniques only account for nonlinear vertical motion, and Finite Elements (FE) nonlinear analysis that considers contact between coils can be very expensive. A 2D model based on equivalent beam and penalty-based contact algorithm is developed for efficient yet realistic prediction of non-uniform spring deflection. The proposed model is tested versus FE, where the helical wire is modelled using beam elements. Two scenarios are taken into account: a cylindrical spring in compression/bending and a progressive conical spring under simple compression. It is shown that the proposed model matches FE at a very low computational cost.
Amplification of laser diode-induced photoacoustic signals for non-destructive testing of mechanical components
Authors: Gulino Michelangelo-Santo , Banelli Luca , Vangi Dario 
Published: March 2021

Abstract
The present work highlights that the laser diode, acting as an ultrasonic source by photoacoustic effect, can be successfully employed for defect detection in mechanical components; the performed investigation specifically involves a railway axle with cracks on the body and fillets, respectively 13 mm-deep and 2 mm-deep. To ease the inspection process, a methodology for amplification of the ultrasound is introduced which is based on the appropriate choice of the TTL signal modulating the diode; amplification is achieved by constructive interference between two ultrasonic signals: the first is induced by the dilation resulting from the laser ignition, the second conversely derives from the contraction obtained when the laser is powered off. The proposed amplification methodology allows ultrasonic energy to be focused in a narrow range of frequencies, promoting the use of traditional detection devices like narrowband probes. The developed inspection system, which takes advantage of a 20 W source, enables the identification of the ultrasonic pattern and defect detection regardless of the application of post-processing techniques on the acquired signals: allowing for excitation of high-amplitude ultrasound without directly contacting the component, the laser diode represents a suitable source for the non-destructive inspection of the axle while it rotates (i.e., during operation). Thanks to the cost reduction achieved in comparison with the use of more traditional pulsed lasers, the diode lends itself to large-scale application in the field of non-destructive testing on mechanical structures.
Magnetostructural assessment of DEMO TF coils with ENEA Winding Pack configuration
Authors: Giorgetti F , Mercuri A , Boso D , Calabrò G , Corato V , Fanelli P , Muzzi L , Stefanini C 
Published: March 2021

Abstract
The present paper deals with a multiphysics study of the DEMO Toroidal Field (TF) coils with Winding Pack (WP) layout proposed by the Italian agency ENEA. The latest WP configuration, so far designed adopting the Wind&React technique, is composed of 202 Nb3Sn rectangular conductors, with steel jacket thickness progressively increased from the plasma-facing side, arranged in 6 double layers. Each conductor is designed to carry an operative current of 73.4 kA (14.8 MAt for one TF coil) and to ensure the requirement of 12 T of magnetic peak field. The electromagnetic (EM) Lorentz forces have been preliminary evaluated with a magnetostatic 3D analysis at different instants of plasma scenario and then used to perform the 3D structural assessment of the TF coil. For both models (i.e., electromagnetic and mechanical), the WP has been represented as a homogenized material with the cyclic symmetry boundary conditions, allowing to reduce the computational effort. In the structural model, a preliminary design of outer inter-coil structures and gravity support have been included allowing them to identify critical locations in a reliable way. In addition to the EM loads at different plasma scenario instants also the cooling down has been considered as loading condition. The stress assessment on the steel Casing was performed, exploiting the stress linearization along several paths chosen in the most critical locations.
Experimental setup for the evaluation of large displacements in the inflected beams sustained to ground
Authors: Marotta E , Iandiorio C , Salvini P 
Published: March 2021

Abstract
In engineering practice, it often occurs to tackle structures with systems of forces such as to induce displacements beyond the linear response. If the material remains in the elastic field, the behaviour is generally addressed as geometric non-linearity. Taking into consideration beam structures subjected to distributed and concentrated loads, the differential equations that describe the structural behavior need to be solved with numerical methods (e.g. Runge-Kutta algorithm or F.E.M.) or analytical perturbative approaches. This work presents experimental results concerning a beam, sustained to the ground, loaded to own weight and lifted by concentrated loads at the free-end. The loads are such as to cause very large displacements. The work describes some useful tricks to carry out the tests with good precision and repeatability. Several experimental data are compared with numerical results.
Analysis of the blast wave – structure interface phenomenon in case of explosive events
Authors: Lomazzi L , Giglio M , Manes A 
Published: March 2021

Abstract
Several structures need their response to blast loads to be investigated to grant an acceptable survivability level. To this purpose, experimental campaigns are complex, but some numerical methods are commonly exploited. The explosion pressure-time history is typically estimated characterizing the detonation of an energetically equivalent explosion involving the detonation of a specific amount of TNT. The pressure-time history at a point, fixed in space, involved by the blast wave is described by the Friedlander equation. A specific approach to modelling the complex blast wave–target structure coupling is reported in the UFC 3-340-02. This method, although consolidated and valid for aerospace, civil and mechanical structure, is not adopted in predictive simulations, which involve naïve methods for characterizing that interface phenomenon. This work aims to give an insight on the blast wave–structure interaction event. A methodological approach combining the Friedlander equation and the theory reported in the UFC 3-340-02 is presented, which confidently characterizes the effects of explosive loads on common structures. This fully analytical method may be implemented into numerical codes to perform simple, but effective, preliminary characterizations of the structural response to explosive loads. Finally, a possible application of the proposed method to thin-walled structures is shown.
Different roles of stacking fault energy and diffusivity in the creep performance of nickel-based single-crystal superalloys
Authors: He Chuang , Huang Taiwen , Yang Wenchao , Wang Xiaojuan , Zhang Jun , Guo Min , Liu Lin 
Published: March 2021

Abstract
Two nickel-based single-crystal (SC) superalloys (designated T6 and T13) were investigated in order to reveal the effects of stacking fault (SF) energy and diffusion on their high-temperature creep behavior. In this study, the effect of dislocation spacing on creep was the same between T6 and T13. The microstructure and deformation rate attained prior to 1% creep were investigated in detail. Several differences were detected in the two superalloys, the reasons for these differences were discussed. The results suggested that the SF energy of the γ matrix was the key factor affecting development of the dislocation network. Because the matrix of the T6 superalloy has lower SF energy than T13, the cross-slipping of dislocation was more difficult in the early stages of creep, which resulted in lower levels of dislocation propagation and of formation of the dislocation network. When creep had entered the steady stage, the key process controlling high-temperature creep was atomic migration in the γ matrix, and the creep rupture life was lengthened by reducing the penetration of dislocations into the γ′ raft and slowing down its topological inversion.