bluuebunny/crossref_metadata_2025_split huggingface dataset:
Editorial
Authors: Furgiuele F. , Bonora N , Quaresimin M. , Meneghetti G. , Livieri P 
Published: February 2023

The Italian Association for Stress Analysis (AIAS) was founded in 1971 by researchers from academia, research centers, and industry. AIAS was intended as a community where to discuss, share, and develop scientific knowledge related to all technical aspects of stress analysis. In the years, from an initial focus on experimental techniques, AIAS contributed considerably to the development of modern numerical methods and computational techniques for mechanical engineering design. In 2015, AIAS turned in the Italian Scientific Society of Mechanical Engineering Design.
Today, AIAS is an institutional partner that supports the instances from academia in the subject area of mechanical engineering design. Every year, AIAS organizes a technical conference offering the possibility to present research updates, share new ideas, and foster collaborations. The AIAS conference has become a fundamental event for all those interested in current developments in mechanical engineering design and stress analysis, where to meet researchers, testing equipment, and software developers.
The 51st AIAS Conference edition was held in Padova, Italy again in presence after two years of online-only events due to the COVID-19 pandemic.
The response of researchers and students has been outstanding: over 200 oral contributions have been presented during the three days of the conference, with four parallel sessions. In addition to the thematic sessions on AIAS traditional subjects, special sessions on additive manufacturing, energy methods for structural analysis, circular design in mechanical engineering, and mechanical behavior under extreme conditions, have been successfully organized with the contribution of the AIAS technical committees.
Among all contributions presented at the conference, 48 have been selected to be published after peer review, in this volume. This was made possible thanks to the active participation of all AIAS members, to the work of the AIAS Scientific Committee and Conference Papers Review panel (Profs Giovanni Meneghetti, AIAS Scientific Coordinator, Luciano Afferrante, Francesco Bucchi, Filippo Cianetti, Enrico Armentani, Marco Sasso). Their outstanding contribution is gratefully acknowledged.

Disclaimer

AIAS2022 Conference was held in presence on Sept. 7-10, 2022. Presentations were arranged in four parallel sessions with a time slot of 15 min assigned to each presenter. Approximately 250 participants attended the conference during the three days event. All sessions have been continuously monitored by the organizers to provide technical support. The conference ran smoothly, and the participants’ feedback was very positive.
Vibro-Acoustic Modulation with broadband pump excitation for efficient impact damage detection in composite materials
Authors: Loi G , Marongiu G , Porcu M C , Aymerich F 
Published: February 2023

Abstract
In the past few decades, the need for efficient and reliable Structural Health Monitoring strategies has led to the development of several approaches for damage detection and characterization purposes. Among them, the Nonlinear Vibro-Acoustic Modulation (VAM) exploits the modulation arising from the interaction of two concurrently applied driving waves, namely the probe and the pump excitations, in the presence of nonlinear scatters such as cracks and defects. Therefore, the VAM provides information on the emergence of internal damage by extracting the nonlinear modulated components of the response of a damaged system. Originally proposed for granular media, the method has shown to be effective in detecting the presence of defects also in metals and composite materials. Nonetheless, its efficacy is highly affected by the excitation frequencies, which are usually chosen among the system resonances. The need for a preliminary modal analysis and, at once, the risk of selecting pump-probe frequency combinations with low sensitivity to damage may make the procedure time-consuming and not fully reliable, preventing the VAM technique from being widely accepted as a robust monitoring tool. To overcome these limitations, a broadband excitation may be used. This study assesses the effectiveness of the VAM technique when a combination of a frequency-swept pump excitation and a mono-harmonic probe wave is applied to drive the sample. Experimental tests were conducted on a composite laminated beam mounted on an electrodynamic shaker and tested in both pristine and damaged conditions. Low-profile surface-bonded piezoceramic transducers were used for both probe excitation and sensing. Barely visible impact damage (BVID) was introduced in the composite beam to examine the potential of the approach for the detection of very small, localized damage. The results show that the use of VAM with a broadband low-frequency excitation may be an effective option for identifying nonlinearities associated with typical damage occurring in composite structures.
Fatigue health monitoring of AISI 304 notched specimens by means of thermographic analysis and UT-based measurements
Authors: Panella F W , Pirinu A , Saponaro A , Nobile R , Rucco R , Renna V 
Published: February 2023

Abstract
The damage accumulation and the cracks development due to fatigue loads are the main failure mechanisms that occur in metal structures. Therefore, the prediction of structural damage is critically important for the safe and reliable operation of complex engineered systems. In the present work, the evolution of fatigue damage was monitored by infrared thermographic and ultrasonic measurements by means of piezoelectric sensors (PZTs) applied to a batch of notched specimens in AISI 304 stainless steel. Concerning the ultrasonic data, a linear and non-linear frequency study was carried out on the data acquired at various steps during the fatigue life through an appropriate MATLAB analysis algorithm based on the Fast Fourier Transform (FFT). In details, the proposed damage parameters related to thermal variations and the peak-to-peak signal voltage (Vpp) were considered to evaluate the fatigue damage process. Regarding the IRT technique, the thermographic monitoring inspection is implemented with measurements processed in MATLAB to estimate damage indices related to the fatigue damage of the same specimens. The results of the thermal analyses were finally compared with the data of the ultrasound measurements obtained to provide complementary information on the prediction of fatigue damage. The experimental results indicate an interesting increase in the proposed damage parameters that could be associated with an irreversible change due to fatigue damage at the notch tip. The final propagation phase of the crack, instead, is characterized by a quick data variation in agreement with the stiffness reduction. The applied Monitoring strategies has proved efficient for detecting damage induced by fatigue in metal materials.
An innovative experimental energy-based approach for the life prediction of notched details
Authors: Crisafulli D , Foti P , Santonocito D 
Published: February 2023

Abstract
Fatigue assessment of mechanical components can be very challenging due to the presence of macroscopic defects and notches. However, local approaches as the Stain Energy Density, have shown how the fatigue resistance is strictly related to the local stress field near the notch tip and not on the overall dimensions of the component. It is necessary to know some peculiar material’s parameters to apply those local approaches. A short way to obtain such parameters can be to apply Thermographic Methods, such as the Risitano’s Thermographic Method and the Static Thermographic Method, monitoring the energy release during stepwise fatigue and static tensile tests. In this work, experimental tests were performed on plain and double edge steel notched specimens. The SED method has been applied through finite element models, with the easy application of the volume-free procedure, to evaluate its trend at several stress levels. The analysis of the energy release and of the local averaged strain energy density during a static tensile test may be adopted as a novel approach to relate the local stress state with a macroscopic stress value that introduce in the material the first micro plasticization leading to the failure of the component.
An analysis of the dependence of the material length parameter a0 on the stress ratio
Authors: Atzori B , Rigon D , Meneghetti G 
Published: February 2023

Abstract
Safe life approaches in notch fatigue of metallic components rely on the knowledge of the material response to fatigue stresses at notches, which is typically quantified by a material-dependent length parameter. As a general material behaviour, such material parameter depends on several factors and one of the most important of them is the mean stress. The present study is focused on the El Haddad-Smith-Topper material length parameter a0 for analysing under which circumstances and to which extent it may vary with the applied mean stress or stress ratio. The analysis starts by considering the broader problem of the mean stress influence on the fatigue limit of plain material, blunt and sharp notches and cracks. Eventually, an analysis of previous sets of experimental data on wrought steels led to simple relations for estimating the a0 parameter at different stress ratios on the basis of the sole Vickers Hardness
Correlation between Preload and Geometric Characterisation of metal meshes for space antenna reflectors
Authors: Salvini P , Marotta E 
Published: February 2023

Abstract
The paper deals with digital image processing techniques to analyse the shape of the main voids in the metallic mesh of large deployable antennas. The shape of the holes in the mesh influences the electromagnetic performances as the working frequencies and the polarisation effects. The analysis compares two types of mesh subjected to a series of equal loads in two directions; for this task, a dedicated testing machine is used. The paper presents an approach to defining an effective and averaged repetitive pattern. Thus, a statistical point of view of the entire mesh is given, applicable to studying the behaviour of a full reflector, to avoid being affected by local texture defects.
Analysis of Wind Turbine Pitch 4-Point Contact Bearing
Authors: Porziani S , Biancolini M E , Brutti C 
Published: February 2023

Abstract
In the field of renewable energy source, the wind power is certainly one of the most important and therefore the industrial and research community are devoting increasing attention to the design, construction, management and maintenance of wind turbines. Due to the relevance, technical, economic and social of this type of installation the correct maintenance is actually a crucial challenge. As in all mechanical engineering applications, numeric models, FEM based, are widely used during both the design step and monitoring on site. In fact, in the frame of Structural Health Monitoring (SHM), the availability of a Digital Twin is fundamental to interpret the signals coming from the sensors and to check the state of wear and the progression of any damage. In general, this numerical tool must have a good accuracy and a great rapidity of response. For this reason it is essential to develop condensed and reliable models of the main elements able to represent the real behaviour of the component without excessively increasing of computational costs. One of the most important element is the pitch variation slewing bearing, which allows the optimal wing orientation. Unfortunately, a complete numeric model of the bearing requires very large dimension and so the real time reply, necessary to SHM, is difficult. In this paper, to overcome this problem, a new simplified model is proposed to represent the array of spheres and its contact condition with the rings of the bearing. The new approach is based on the adoption of a toroid-shaped element replacing the rolling elements. To study this solution, a full-detailed model of a typical slewing bearing for pitch variation has been used to properly set up the contact model and to tune the properties, geometrical and elastic, of the equivalent toroidal body. The main feature of this approach is that, with a relatively low calculation effort, the deformation behaviour and the stress state of the elements connected to the bearing is available in an easy and accurate way. Then, the comparison in real time of the numerical results with the corresponding experimental ones from the site allows to deduce initiation and growth of a damaging process.
Scooter Tire Pressure Influence on a Hard Braking Manoeuvre
Authors: Failli M , Fontanelli T , Paoletti E , Bartolozzi M , Berzi L , Savino G 
Published: February 2023

Abstract
The mortality of road accidents quadruples when, in addition to motorists, a motorcyclist is also involved. The higher mortality is influenced by the greater exposure of the rider to injuries during the impact. This problem can be mitigated by reducing, even slightly, the impact’s speed. Bench tests carried out by previous studies showed a considerable influence of the inflation pressure on the properties of motorcycle tires. It could therefore have significant effects on the deceleration achievable under braking. This study aimed to evaluate the effect of inadequate tire inflation pressure (excessive or insufficient) on the average deceleration achievable during a hard braking manoeuvre performed only with the rear wheel and with ABS intervention. Experimental tests were carried out on a Piaggio Beverly S 300 in a controlled road environment closed to traffic. Different inflation pressures of the rear braking tire were tested during multiple runs. The data were acquired through a smartphone used as an IMU. At the nominal pressure of 2.4 bar the measured average deceleration was 3.69 m/s2 (SD = 0.12 m/s2). When increasing the pressure to 3.0 bar and decreasing it to 1.8 bar the average deceleration was reduced respectively to 3.67 m/s2 (-0.8%, SD = 0.10 m/s2) and 3.59 m/s2 (-3.0%, SD = 0.16 m/s2). The reduction in achievable deceleration was partly mitigated by the reduced load transfer on the rear tire, which partially compensated for the reduction of the braking force coefficient. The results showed that a moderate inflation pressure variation on the rear braking tire modestly influences the achievable average deceleration.
Modelling, testing and validation of an innovative AEB control logic on a Hardware-in-the-loop test bench
Authors: Veneroso L , Alfatti F , Annicchiarico C , Capitani R 
Published: February 2023

Abstract
AEB, autonomous emergency braking, is an active safety system designed to prevent vehicle frontal collision. The most diffused AEB systems are based on simple Bang Bang control logic, which could often avoid, or at least mitigate collision effects, but their effectiveness can still be improved by increasing system repeatability. The aim of this study is to model and test an innovative AEB control logic that will increase system reliability by compensating for the non-immediate response of the braking system to braking requests. Using a hardware-in-the-loop test bench with two different braking systems implemented, the new controller was tested simulating the CCRs and CCRm scenarios, used by Euro NCAP for AEB system assessment. By compensating for the delay introduced by the response of two different braking systems, the innovative control logic stops the VUT, Vehicle Under Test, at the desired safety distance from the GVT, Global Vehicle Target.
Crack propagation in viscoelastic finite-sized solids: theory and experiments
Authors: Violano G , Carolis S De , Palmieri M E , Carbone G , Tricarico L , Demelio G P , Afferrante L 
Published: February 2023

Abstract
The problem of crack propagation in viscoelastic materials is of great interest given the numerous engineering applications of such materials. Due to viscoelasticity, even the study of the basic Mode I opening represents a tricky theoretical challenge. Indeed, existing theories adopt important approximations such as i) simplistic constitutive behaviour, ii) steady-state crack propagation, iii) infinite domain of the system. In this work, we revise the theory of Persson & Brener for systems of infinite domain; specifically, we propose a solution to take into account size effects in a viscoelastic plate. The theory allows to consider the realistic constitutive behaviour of viscoelastic materials and to predict the dependence of the energy release rate with the crack tip speed. Comprehensive experimental investigations are performed to corroborate our theoretical predictions. First, dynamic mechanical analysis (DMA) is performed to characterize the complex viscoelastic modulus of PolyTetraFluoroEthylene (PTFE). Second, tensile tests are carried out on cracked PTFE samples, and pictures are recorded with an image acquisition system. Moreover, a point tracking algorithm is developed to measure the crack length and opening displacement. Moving from small to high crack tip speeds, the fracture process becomes less ductile and an increase in the maximum load is observed. In addition, experimental data show that the inclusion of finite-size effects in the theory is crucial for accurately estimating the energy release rate.
Lifetime assessment of the rear axle for an off-road vehicle in a fatigue test bench by means of the Peak Stress Method
Authors: Pelizzari J , Salvagno P , Dengo C , Campagnolo A , Meneghetti G 
Published: February 2023

Abstract
In this study the Peak Stress Method (PSM) has been applied to the fatigue assessment of the welds of an axle equipped in an off-road vehicle. In the fatigue design of welded joints, the PSM is a FE-based method to rapidly evaluate the NSIFs relevant to the opening, sliding and tearing modes by means of the linear elastic peak stresses extracted from the FE model. First, an axle, which consists of a central body and two lateral branches composed by several plates welded to a tube, has been fatigue tested under a vertical load in a test bench designed to replicate the frame-axle interface. Then, an FE model of the axle has been calibrated to simulate the behaviour observed during the fatigue test, where the reaction forces and the strains at pre-defined locations have been considered. Once the FE model has been calibrated, the PSM has been applied to the welds of the axle, taking advantage of an automatic procedure, and the crack initiation location has been estimated. Finally, the theoretical estimations have been compared with the experimental datum.
Effective ways to compare two families of freight trains
Authors: Cantone L 
Published: February 2023

Abstract
The paper shows several use cases of the “relative approach” method, envisaged by international recommendations, for evaluating the safety of two families of freight trains. This is relevant when a decision is needed about a new technology or a new operating mode of freight trains to keep the same safety as existing trains. The paper discusses the heterogeneity of the database of trains and provides examples of the classic application of the “relative approach”, highlighting the effect of train operation. Furthermore, it shows the application to DAC and radio-controlled Traction Units. Finally, it introduces the “Iterative Proportional” algorithm to generate a freight train from an existing one just by changing the hauled mass of each wagon. This algorithm is helpful when the “relative approach” is applied to trainsets having articulated wagons and running with a similar braking regime.
Artificial intelligence based approach for categorization of COVID-19 ECG images in presence of other cardiovascular disorders
Authors: Chaitanya M Krishna , Sharma Lakhan Dev , Rahul Jagdeep , Sharma Diksha , Roy Amarjit 
Published: February 2023

Abstract
Coronavirus disease (COVID-19) is a class of SARS-CoV-2 virus which is initially identified in the later half of the year 2019 and then evolved as a pandemic. If it is not identified in the early stage then the infection and mortality rates increase with time. A timely and reliable approach for COVID-19 identification has become important in order to prevent the disease from spreading rapidly. In recent times, many methods have been suggested for the detection of COVID-19 disease have various flaws, to increase diagnosis performance, fresh investigations are required. In this article, automatically diagnosing COVID-19 using ECG images and deep learning approaches like as Visual Geometry Group (VGG) and AlexNet architectures have been proposed. The proposed method is able to classify between COVID-19, myocardial infarction, normal sinus rhythm, and other abnormal heart beats using Lead-II ECG image only. The efficacy of the technique proposed is validated by using a publicly available ECG image database. We have achieved an accuracy of 77.42% using Alexnet model and 75% accuracy with the help of VGG19 model.
Failure mode change and material damage with varied machining speeds: a review
Authors: Zhang Jianqiu , He Binbin , Zhang Bi 
Published: February 2023

Abstract
High-speed machining (HSM) has been studied for several decades and has potential application in various industries, including the automobile and aerospace industries. However, the underlying mechanisms of HSM have not been formally reviewed thus far. This article focuses on the solid mechanics framework of adiabatic shear band (ASB) onset and material metallurgical microstructural evolutions in HSM. The ASB onset is described using partial differential systems. Several factors in HSM were considered in the systems, and the ASB onset conditions were obtained by solving these systems or applying the perturbation method to the systems. With increasing machining speed, an ASB can be depressed and further eliminated by shock pressure. The damage observed in HSM exhibits common features. Equiaxed fine grains produced by dynamic recrystallization widely cause damage to ductile materials, and amorphization is the common microstructural evolution in brittle materials. Based on previous studies, potential mechanisms for the phenomena in HSM are proposed. These include the thickness variation of the white layer of ductile materials. These proposed mechanisms would be beneficial to deeply understanding the various phenomena in HSM.
Experimental investigation and process parameter optimization in cold metal transfer welding for SS304L using response surface method
Authors: Ainapurapu Sirisha Bhadrakali , Devulapalli Venkata Anantha Ramasastry , Theagarajan Ram Prabhu 
Published: February 2023

AbstractCold Metal Transfer (CMT) welding was used to join SS304L plates using SS308L MIG wire. The effects of current, the distance between nozzle and tip, welding speed on strength, hardness and surface roughness of welded zone in the CMT process using response surface methodology were investigated in the present study. The outcomes show that current is having a significant effect on the outputs. Also, current interacting with weld speed is showing its mark on the output variables like tensile strength, hardness and surface roughness. Finally, optimal results are found and the experimental values are in coincidence with the predicted values.
Nature-inspired metaheuristic optimization algorithms for urban transit routing problem
Authors: Li Qian , Guo Liang 
Published: February 2023

Abstract
Designing urban transportation networks is a technological and social reality defined as a decentralized polynomial NP-Hard problem. In order to efficiently resolve this issue, several nature-inspired metaheuristic approaches have been proposed. Although these methods are crucial to resolving urban transportation network challenges, no comprehensive study has been conducted to address these concerns. Thus, this study provides an in-depth examination of nature-inspired metaheuristic methods applied to urban transmission. The current study aims to demonstrate the significant benefits of optimization algorithms in solving the Urban Transit Routing Problem (UTRP).