In the current scientific context, Basalt Fibres have been proposed as sustainable alternative to synthetic reinforcements in polymeric matrices, thanks to their relatively low cost, good mechanical properties and reduced environmental impact. The aim of this work is to assess the possibility of replacing Glass Fibre with Basalt Fibre Reinforced Composites for structural application. For this purpose, several static tests have been performed in basalt-vinylester and glass-vinylester specimens, and a comparison of the failure behaviour has been conducted. Additionally, the two different failure mechanisms have been analysed with IR Thermography. Results demonstrate that Basalt Fibre composites failure behaviour is advantageous for design purposes, highlighting their potential to replace fibreglass in the near future.

The design of mechanical components in recent years has been experiencing a series of innovative processes which, in addition to the classic methodologies, also support topological and structural optimization considering the product life cycle (LCA). These innovative aspects make it possible to reduce the weight of the components and the impact on the environment, both during production and during operation. The purpose of this work is to create a tool for the "intelligent design" of automotive components through optimization algorithms called "Smart Design". The final intent is to create a multidisciplinary methodology for mechanical design that combines topological optimization techniques and product life cycle analysis. The single studies, from the creation of the CAD and the finite element analysis, up to the topological optimization and the LCA analysis, are managed by a single code generated in the Matlab (R) environment. The work is carried out in collaboration with Ferrari S.p.a.

Thanks to the development of additive manufacturing techniques, prosthetic surgery has reached increasingly advanced levels, revolutionizing the clinical course of patients with joint arthritis. 3D printing has made it possible to obtain customized prostheses based on patient needs, using high-performance materials. However, wear caused by regular gait activities such as walking, sitting, or running, leads to the deterioration of the material used in the joint. Thus, the use of traditional materials has gradually been replaced with more performing ones which have made it possible to obtain customized devices based on patient needs and, therefore, more effective. Numerical techniques have recently been adopted, such as the Finite Element Method (FEM), to support the experimentation, allowing the calculation of the useful life and the optimization of the prostheses’ functionality to accurately evaluate the distribution of the load on the prosthesis. The present work aims to develop an algorithm that optimizes hip replacement mechanically using a machine learning algorithm coupled with multi-body and finite element model simulations.

High Density Polyethylene (HDPE) represents one of the best choices for water and gas distribution pipeline thanks to its light weight and good mechanical performance. One of the strengths of this plastic material is the possibility to join it via welding adopting a procedure according to the standard. However, the welding procedure can severally alter the mechanical performance of the material under service loads. In the present work comparison between virgin and welded HDPE specimens is carried out adopting rapid approaches, such as the Risitano’s Thermographic Method and the Static Thermographic Method, monitoring the evolution of the specimen’s superficial temperature under static tensile and fatigue tests. Mechanical performance has been compared, as well as the fatigue limit obtained with traditional fatigue tests, showing good agreement. Reliable fatigue data have been obtained in a very short amount of time and with few specimens by adopting Energy Methods.

Background and aim:Healthy patellofemoral (PF) joint mechanics are critical to optimal knee joint function. Patella plays a vital role in distributing quadriceps load during the knee extension. Patellar tracking, not physiological tracking, causes an increase of strains in PF ligaments, peaks of localized stress of soft tissues and articular cartilage and bony parts, and knee pain; these problems lead to complications such as bone abnormalities and osteoarthritis. This research aimed to develop a Finite Element (FE) model to evaluate patellar instability due to the medial retinaculum asymmetric loading effect. Methods:A numerical model of the knee was obtained by matching nuclear magnetic resonance (MRI) for soft tissues and computerized tomography (CT) for bones, carried on a normal adult. Loading setup was chosen by using literature data. The intensity of the muscle forces was calculated by a static optimization taking into account ground reaction and knee flexion/extension during walking. The effect of patellar instability was obtained by gradually unbalancing this symmetry, one side was unloaded till 90 N, and the other loaded till 110 N. Results:Unbalanced forces of 10 N acting on the retinaculum alone can produce a real difference in displacements of about 7 mm, and an increment of about 44% on patellar contact forces. Conclusion:This research demonstrated how an unbalanced forces acting on the retinaculum can produce significant patellar instability. Patellar instability starts at 25-30° of the knee flexion angle but tends to appear at 15° when the unbalanced muscular loading conditions are acting.

Additive Manufacturing (AM) allows the creation of mechanical components and biomechanical devices with low weight and reduced material consumption compared to traditional manufacturing techniques. Despite design opportunities increase, on the other hand, also the process parameters to consider when dealing with AM are relevant on the mechanical performance. It is of fundamental importance to assure the structural integrity and reliability of such components. Energy release could give relevant information on the mechanical performance of the material; hence the Static Thermographic Method (STM) has been proposed as a rapid test procedure to assess the initiation of damage within the material monitoring the temperature evolution during static tensile tests. The aim of the present work is to compare the energy release of a stainless steel during static tensile tests. Specimens made of AISI 316L were produced with the same geometry, both with traditional and AM techniques. A comparison on the microstructure has been also performed in order to assess the possible cause of failure under static loads.

The aims of this study were to evaluate the impact of the COVID-19 pandemic on emergency and elective hand surgery in four Italian regions that had either a high (Lombardy and Piemonte) or a low (Sicilia and Puglia) COVID-19 case load to discuss problems and to elaborate strategies to improve treatment pathways. A panel of hand surgeons from these different regions compared and discussed data from the centers they work in. The COVID-19 pandemic had an enormous impact on both elective and emergency surgery in Italy, not only in highly affected regions but also - and paradoxically even at a higher extent - in regions with a low COVID-19 case load. A durable and flexible redesign of hand surgery activities should be promoted, while changing and hopefully increasing human resources and enhancing administrative support. Telematics must also be implemented, especially for delivering rehabilitation therapy. (C) 2020 Published by Elsevier Masson SAS on behalf of SFCM.

Static Thermographic Method is a rapid test procedure able to predict the fatigue limit of the material evaluating the end of the thermoelastic phase during a static tensile test. In order to investigate the energetic release of the material, experimental tests have been carried out on double edge steel notched specimens. During the test, the surface temperature was monitored with an infrared camera and the true stress-strain curve of the material was retrieved. Numerical simulations have been carried out to predict the temperature evolution of the material under monotonic load. The relationship between the elasto-plastic behavior and the energetic release has been investigated comparing numerical and experimental data. The rise of irreversible plastic deformation severally affects the temperature trend introducing an additional heat amount that leads to a deviation from the linearity of the thermoelastic effect. The analysis of the temperature evolution 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.

Structural S355 steel is widely applied in various sectors. Fatigue properties are of fundamental importance and extremely time consuming to be assessed. The aim of this research activity is to apply the Static Thermographic Method during tensile tests and correlate the temperature trend to the fatigue properties of the same steel. The Digital Image Correlation (DIC) and Infrared Thermography (IR) techniques have been used during all static tests. The Digital Image Correlation technique allowed the detection of displacements and strain, and so the evaluation of the mechanical properties of the material. Traditional fatigue tests were also performed in order to evaluate the stress-number of cycles to failure curve of the same steel. The value of the fatigue limit, obtained by the traditional procedure, was compared with the values predicted by means of the Static Thermographic Method (STM) obtained from tensile tests. The predicted values are in good agreement with the experimental values of fatigue life.

Topological optimization is a fairly innovative numerical technique that makes it possible to reduce the mass of mechanical components. It is an alternative to the optimizations of shape or geometry that allow to highly improve the efficiency of products. The recent development of metal additive manufacturing technologies allows the production of pieces that were not feasible before, permitting the use of topological optimization in many fields. In the biomedical field, for example, the reduction of prosthetic and orthotic materials allows to save weight, to the advantage of comfort, and to minimize the invasiveness of these systems. In this paper, an optimization of a system consisting of a femoral nail and two screws is carried out. The pieces were obtained by 3D scanning of prostheses, so as to obtain the true geometry. The femur is the standard one in literature. Following topological optimization, a new nail, with a mass of 60% of the previous one, was obtained, without limiting the functionality or the reliability of the product. Results and methodological problems are discussed.

Since its introduction in pipe applications more than 40 years ago, polyethylene (PE) has been taking a growing place in gas and water distribution due to its low cost, lightness and good corrosion resistance. Besides, long-term properties have been steadily rising due to the development of novel PE-based materials. The present highest standard is the PE100 class. Several laboratory tests are used to extract design data for long-term failure-type prediction based on stress and time to failure relationship. It remains difficult to assess the relation between creep and fatigue loadings on the one side. On the other side, the manufacturing process of the test specimens influences considerably the obtained performance for viscoelastic materials subjected to working conditions. In present paper, the mechanical properties of high-density polyethylene (HDPE), PE 100 class, for pipes were investigated using experimental techniques. Thermographic technique was used during the static tests in order to identify the maximum stress zone and also during the fatigue tests to study the temperature evolution of the specimen. The aim of this study is the application of the Thermographic Method for the fatigue assessment of PE100.

The present paper is the result of the collaboration between the Engineering Department of Messina University and the car company Maserati S.p.A. The aim of this paper is to determine the T-N torsion fatigue curve at R= -1 of the mechanical system "front halfshaft" of an existing car. In particular, experimental fatigue tests were carried out in the laboratories of the Engineering Department of the University of Messina. Torsion fatigue tests of the entire mechanical system were carried out on 15 different front halfshafts. Evaluations of the crack propagation and of failure analysis were made to determine the causes of breakage. In conclusion, the T-N fatigue curve of the mechanical system "front halfshaft" has been obtained.

The traditional methods of fatigue assessment of metallic and composite materials are extremely time consuming. The thermographic measurements during static tests can be used to predict the fatigue limit. This procedure has been already applied to composite materials. The aim of this study is the application of this procedure for the fatigue assessment of steel welded joints. Static tensile and fatigue tests were carried out on butt welded specimens, made of S355 steel. Two full-field techniques were applied during the tests: digital image correlation and infrared thermography techniques. Fatigue tests at increasing loads were performed by a stepwise succession in order to apply the Thermographic Method. The value of the fatigue limit, obtained by the traditional procedure, was compared with the values predicted by means of the Thermographic Method during stepwise succession fatigue tests and by means of the infrared thermography technique during static tensile tests. The predicted values are in good agreement with the experimental values of fatigue life. (C) 2017 Elsevier Ltd. All rights reserved.

In this work, more specimens were tested at equal conditions (static compression test) and, during the tests, the released heat for irreversible phenomena was monitored by means of the analysis of the temperature surface of the specimen. In this way, it was possible to estimate the average value of the macroscopic stress ("critical stress") for which local micro cracks begin. The compression static tests (load - machine time) and the related thermal analysis (temperature-machine time) of spots located on the specimen face of the specimens, highlighted the possibility to estimate the value of the compressive load to which there was loss of linearity in the temperature - machine time diagram (Delta t-t). This effect is due to internal heat generated for irreversible phenomena (internal micro fractures). The results show that the "critical stress" has values practically coincident for the points (spots) located in different zones (center or corners of the specimens' surface). Copyright (C) 2017 The Authors. Published by Elsevier B.V.

Today, lightweight and low cost components can be obtained with short fibre reinforced plastics. The recyclable nature of these materials by comparison to thermoset matrixes composites is also clearly appealing. This paper investigates static and fatigue behaviour for a glass-fibre-reinforced polypropylene composite. Tensile tests were carried out using DIC and IR Camera. Stress vs strain curves and temperature evolution associated to the applied tensile stress were determined. The trend of the surface temperature of the specimen during fatigue tests was analyzed. Copyright (C) 2017 The Authors. Published by Elsevier B.V.

Estimation of the fatigue limit for steel ductile materials using non-destructive methods is a topic of great interest to researchers today. In recent years, the method adopted has implemented infrared sensors to detect the surface temperature and correlate it with the fatigue limit. In previous paper, a new energy approach was proposed to investigate the fatigue limit during tensile test. The numerical procedure proposed by Chrysochoos is adopted to clean infrared images and applied to analyse the surface heat sources during tensile test. AISI 304 specimens with rectangular cross-sections are tested. Moreover fatigue tests at increasing loads were carried out on steel by a stepwise succession, applied to the same specimen, for applying the thermographic method. The predictions of the fatigue limit, obtained by the analysis of the energy evolution during the static tests, were compared with the predictions obtained applying the thermographic method during fatigue tests.

Two full-field techniques were applied for the study of the base material and welded specimens, made of S690QL steel: digital image correlation and thermographic techniques. Static and fatigue tests were carried out. The thermographic measurements can be used to predict the fatigue, with a great saving in time and effort. Fatigue tests at increasing loads were carried out by a stepwise succession, applied to the same specimen, for applying an energy-based approach. The predictions of the fatigue life, obtained by means of the Energy Approach, were compared with the values obtained by the traditional procedure.

During their operation, modern aircraft engine components are subjected to increasingly demanding operating conditions, especially the high pressure turbine (HPT) blades. Such conditions cause these parts to undergo different types of time-dependent degradation, one of which is creep. A model using the finite element method (FEM) was developed, in order to be able to predict the creep behaviour of HPT blades. Flight data records (FDR) for a specific aircraft, provided by a commercial aviation company, were used to obtain thermal and mechanical data for three different flight cycles. In order to create the 3D model needed for the FEM analysis, a HPT blade scrap was scanned, and its chemical composition and material properties were obtained. The data that was gathered was fed into the FEM model and different simulations were run, first with a simplified 3D rectangular block shape, in order to better establish the model, and then with the real 3D mesh obtained from the blade scrap. The overall expected behaviour in terms of displacement was observed, in particular at the trailing edge of the blade. Therefore such a model can be useful in the goal of predicting turbine blade life, given a set of FDR data. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016.

In the last years, several approaches were developed in literature for predicting the fatigue strength of different kinds of materials. One approach is the Thermographic Method, based on the thermographic technique. This study is devoted to the development of a theoretical approach for modeling of surface and undersurface fatigue crack initiation and temperature evolution during ultrasonic fatigue test. The proposed model is based on the statistical description of mesodefect ensemble and describes an energy balance in materials (including power of energy dissipation) under cyclic loading. The model allows us to simulate the damage to fracture transition and corresponding temperature evolution in critical cross section of a sample tested in very high cyclic fatigue regime.