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Precision machining operations often lead to the failure of protective coatings on cutting tools due to common issues such as cracking, delamination, and peeling from cyclic impacts. While material selection and structural design are crucial for enhancing impact resistance, they primarily focus on static performance with limited consideration from the dynamic sights. This paper presents a novel dynamic design method for coatings, viewed through the lens of stress waves. We investigate the propagation behavior of stress waves in TaN/TiN and CrN/TiN coatings with layered structures. Our findings indicate that the attenuation of stress waves is dominated by the physical properties on both sides of the interface and the stride length. For interfaces with similar physical properties, the attenuation of stress waves is insensitive to the stride length, while for interfaces with different physical properties, the attenuation is regulated by the ratio of single-layer thickness to the full width at half maximum of the stress wave. These insights offer a strategy for extending the life of coatings and improving process safety under dynamic shocks.

The present paper proposes a new approach for the thermomechanical analysis of small satellites. In the first stage, the heat fluxes acting on the exterior surfaces of the assembly are evaluated with the support of the CubeSat Wizard. The orbital parameters employed ensure adequate radiation heat transfer. Afterwards, the temperature distribution of the entire structure is evaluated with the support of the LISA thermal transient environment. The most critical load case is further use for calculating stress and displacement in a static analysis. Two configurations of CardSat nanosatellites are included in the study for comparison.

Thermal interface materials (TIMs), as important materials for heat dissipation of insulated gate bipolar transistor (IGBT) modules, degrade under long-term thermal cycling, resulting in elevated junction temperatures and threatening the safe operation of IGBT modules. In consideration of the thermal coupling effect in IGBT modules, this paper proposes a three-dimensional thermal network model characterizing the TIM degradation. An IGBT module with the TIM is adopted to establish the finite element method (FEM) model, in which the TIM layer is divided into regular areas. The thermal network is established by simulating the heat transfer paths. The thermal impedance in each path is extracted according to the heat flow through its area considering the TIM degradation. Thereby, the impact of thermal coupling and TIM degradation on junction temperature of IGBT modules could be characterized. Furthermore, the proposed thermal network is verified by simulation from calculation accuracy of junction temperature and TIM temperature.

Biofilms are ubiquitous at interfaces of natural and technical origin. Depending on type and application, biofilm formation is desired or has to be prevented. Therefore, reliable detection of initial biofilm growth is essential in many areas. One method of biofilm monitoring is the electrochemical impedance spectroscopy. Among other factors, this method is heavily dependent on the electrode geometry. In order to achieve a high measurement sensitivity, the electrode size must be chosen according to the biofilm that is to be measured. This paper presents an approach for simulating and modeling the optimal electrode geometry for a specific biofilm. First, a geometric model of a biofilm with up to 6000 individual bacteria is generated. The simulated impedances are used to calculate which electrode geometry maximizes sensitivity depending on the biofilm height. In the chosen example of an E. coli biofilm in a nutrient solution, the optimum size of an interdigital electrode (bar gap equals width) was 2.5 µm for a biofilm height of up to 2 µm. The used algorithms and models can be simply adapted for other biofilms. In this way, the most sensitive electrode geometry for a specific biofilm measurement can be determined with minimal effort.

The accurate modeling of wolfberry plant morphology is the basis for theoretical and simulation analyses of the wolfberry picking process. The curved shape of the fruit branches makes it challenging to model Lyciumbarbarum (wolfberry) plants. This paper establishes a three-dimensional model of the branches under no gravity through field measurements, and then assesses the morphology of the branches under gravity load, fruit load, and branch load using finite element simulation. An orthogonal rotation combination experiment determined the relationship between branch morphology, length, growth angle, and growth mode parameters. The p-values of the prediction model were 0.0001, 0.0067, and 0.0203, respectively. Finally, the bending shape of the actual branches was verified against the branches generated by the prediction model. The experimental results show that the prediction model accurately models the fruit-bearing branches of Lycium barbarum. This paper introduces a method to quickly predict the bending shape of fruit-bearing branches of Lycium barbarum, providing a theoretical basis for rapid modeling of the L. barbarum plant and a simulation analysis for its harvesting.

Flip anchors are a kind of ground anchor that rotate and open in the ground to attain pull-out resistance without the use of grout. Compared to ordinary grouted ground anchors, flip anchors can be driven into the existing ground quickly and are suitable for the emergency reinforcement of slopes. However, little research has been done on the slope reinforcement effect of flip anchors. In this paper, experiments on a model slope reinforced by plate anchors or flip anchors were conducted. During the experiments, vertical loading with a rigid loading plate was applied to the shoulder of the model slope to investigate its stability. Experiments were firstly conducted with and without model plate anchors under a plane strain condition. Then, experiments were conducted using actual flip anchors under a three-dimensional condition. In these experiments, the depth of the anchor plates, h, and the installation state of the anchor heads of the flip anchors (open or closed anchor head condition) were varied. After the experiments, corresponding numerical simulations (FEM) were conducted, and a subloading tij model was applied to describe the soil behaviour. The numerical method used in this research successfully reproduced the reinforcing effect of the flip anchors. According to the test and calculated results, compared with the cases without reinforcement and with plate anchors, the effectiveness of the flip anchors for slope stability was verified. Moreover, the flip anchors installed under the closed anchor head condition required a larger displacement to produce a reinforcing effect than the anchors installed under the open anchor head condition.

This paper addresses the localization of Partial Discharge through a 3D Finite Element Method analysis of acoustic wave propagation inside a 3-phase 35kV transformer with the help of COMSOL Multiphysics software. Due to the complexity inside transformers, acoustic waves generated by PDs cannot simply be detected with typical acoustic sensors, especially when PDs happen inside inner windings. These waves are distorted and attenuated along with their propagation. The type, number, and position of sensors are essential factors in PD localization inside a transformer. A new installation arrangement of fiber-optic acoustic sensors inside the transformers is proposed with this information. This array of acoustic sensors has significant effects on PD localization accuracy and has immunity from on-site noise and interference; more importantly, they can be installed after transformer manufacturing. They are reachable if needed to be repaired or replaced. Several numerical studies have been carried out considering different PD source positions, and the Levenberge-Marquardt algorithm is employed for solving localization equations.

Ballast layer is the most weak element of railway track that causes track geometry deterioration. At the same time,it is subjected to intensive particle breakage during the corrective tamping. This causes high maintenance costs of ballasted track. The present paper is devoted to the study of tamping methods. The present machine tamping methods are considered and compared. The possible influence of the tamping technology on the ballast-related maintenance costs is analyzed. The side tamping technology is studied in detail with theoretical and experimental methods. The process of material transport during the side tamping is studied using a scale model of ballast layer and photogrammetric measurements. A theoretical finite element model (FEM) is validated to the experimental results. The study shows that the side tamping is a promising method for the development of a universal, superstructure independent tamping technology.

Handling plastic waste through recycling allows extending the life of polymeric materials, avoiding recurrence to incineration or landfilling. In contrast with traditional mechanical recycling technologies, chemical recycling enables the obtention of the virgin monomers by means of depolymerisation to create new polymers with the same mechanical and thermal properties as the originals. Research presented in this paper is part of the polynSPIRE project (Horizon 2020 European funding programme) and develops and scales-up a heated reactor to carry out the depolymerisation of polyamide-6 (PA6), polyamide-6,6 (PA66) and polyurethane (PU) using microwave (MW) technology as the heating source. The purpose is to design and optimize a MW reactor using up to eight ports emitting electromagnetic waves. Finite element method (FEM) simulation and optimisation are used to design the reactor, considering as parameters the data obtained from experimental dielectric testing and lab-scale characterisation of the processes and materials studied. Two different COMSOL Multiphysics modules are involved in this work: Radio Frequency (RF) and Chemical Reaction Engineering (RE), to simulate the reactor cavity using two frequency levels (915 MHz and 2.45 GHz) with a power level of 46 kW, and the chemical depolymerisation process, respectively. A sensitivity study has been performed on key parameters such as the frequency, the number of ports, and position inside the reactor to consolidate the final design. It is expected that these results assist in the design and scale-up of microwave technology for the chemical recycling of plastics, and for the large-scale deployment of this sustainable recovery alternative.

Laser-ultrasonic waves are used in nondestructive inspections because they can be excited on arbitrarily shaped surfaces by irradiation of a pulsed laser from a distance. During the non-contact scanning of a laser, the waveform of excited ultrasonic wave is changed because the incident angle varies substantially. The change of the waveform will be more obvious for carbon fiber reinforced plastics (CFRP) laminates that have anisotropic properties. In order to guarantee the inspection, in this paper, we investigated the generation of ultrasonic waves in CFRP laminates by a laser irradiation with various incident angles and azimuth angles. Firstly, we constructed a simulation model: the thermal force field caused by the laser absorption is derived from a heat conduction equation, and it is introduced into an FEM software for analyzing the propagation behavior of generated ultrasonic waves. Then, the simulation result is compared with an experiment result. Through the FEM analysis, we found that the amplitude of the excited waves has an obvious directivity because of the strong anisotropy in the thermo-elastic property of the CFRP. In addition, the change in propagation behavior in the case of a small incident angle of 30° was found to be inconspicuous. However, when the incident angle of the laser beam is larger than 60°, the directivity pattern changes depending on the azimuth angle. Thus, it is important to control the incident angle and direction when a laser ultrasonic inspection is applied to CFRP structures.

Grain loss in the harvesting process of combine harvesters not only causes economic losses to farmers but also affects the soil environment because of the lost grain covering the soil, influencing crop growth in the next season. Grain sieve loss-monitoring sensors represent an important accessory in combine harvesters, as they can not only provide current grain loss levels for the operator to adopt a rational action in time but also serve as an important performance signal for the control system. To reflect the rice grain sieve loss level of combine harvesters in real time, an indirect grain sieve loss-monitoring system is proposed in this paper. First, the grain collision rise time was obtained by the finite element method (FEM), and the parameters of the grain loss sensor signal processing circuit were determined accordingly to upgrade the monitoring accuracy. Then, grain loss distribution behind the cleaning shoe was analyzed in detail under different working parameters. Grain loss distribution functions at the end of the sieve and a monitoring mathematical model with relevant variables were established based on the laboratory experiment results. Finally, calibration experiments were carried out to verify the measurement accuracy of the sensor on a cleaning test bench, with an obtained relative monitoring error ≤6.41 % under different working conditions.

In the paper a numerical comparative analysis of stresses in a steel die com-pressed by a ring during the extrusion process was presented. In the research, three design solutions of the die were used. The solutions vary depending on the quotient of the wall thickness of the die insert and the wall thick-ness of the compression ring while maintaining a constant tool diameter. The stresses occurring in the areas of the ring and the die were calculated depending on the design version of the tool and the pressure value. The anal-ysis was carried out for the quotients of the die wall thickness to the ring wall thickness of 0.57, 1 and 1.75 and three press-in values of 0.004, 0.008 and 0.016 mm. The conducted research allowed determining the impact of the die design and assembly interference on the load bearing capacity. It was discovered that the use of a die insert with a smaller thickness com-pared to the thickness of the compression ring was the most advantageous from the point of view of the circumferential stresses.

The submitted paper deals with the simulation of thermal cycles during laser welding of aluminum sheets using Finite Element Method (FEM). After the design and creation of the simulation model, the simulation results were verified by the thermal cycles measured during the experiment on real samples. Verification has shown that, despite the differences that have resulted from some simplifications, the proposed model corresponds to the actual behavior of the material used during the laser welding process.

The fatigue life curves of materials are very sensitive to the magnitude of the stress amplitude. A small change or inaccuracy in the determination of the stress value causes large changes or inaccuracies in the calculated fatigue life estimate. Therefore, the use of computer simulations for fatigue life estimation requires a proper model development methodology. The paper is devoted to the problem of the modeling of components in notches using FEM. The modeling parameters significantly influencing the obtained stress results have been defined. Exact analytical solutions served as a benchmark for comparing the accuracy of the stress values obtained using FEM models. For the selected 2D and 3D notched components, diagrams were created for sensitivity analysis of the influence of the mesh element density at the root of the notch in correlation with the exact analytical solution. The findings from model building were applied to model the stress concentration at the root of a V-weld joint in a gas pipeline.

In the detection of small size mass loading, such as a single cell, a micro droplet or an aerosol particle, the sensors with longitudinally coupled surface acoustic wave resonator (LC-SAWR) structure can hardly avoid waveform distortions. The relative size of mass loading to the sensitive surface of the detector is the main factor affecting the response of LC-SAWR. The smaller the relative size, the worse the waveform distortion. In order to avoid influences from the mass loading’s size, in this paper, a transversely coupled SAW resonator (TC-SAWR) was proposed in order to achieve high performance in sensing small size mass loadings. For the design and simulation of TC-SAWR, the two-dimensional coupling of model (2D-COM) theory and finite element method (FEM) were used in this work. In the experiment, SiO2 was deposited on the sensor’s surface as a small size mass loading. The results from simulation and experiment mutually demonstrated the advantage of TC-SAWR to conquer waveform distortion in the detection of small size mass loading.

In the manufacture squirrel-cage rotors of asynchronous motors, a high standard of quality is required in every part of the production cycle. The die casting process usually creates porosity in the rotor bars. This most common defect in the rotor often remains hidden during the entire assembly of the machine and is usually only detected during final testing of the motor, i.e., at the end of the production process. This leads to unnecessary production costs. Therefore, the aim is to conduct a continuous control immediately after the rotor has been cast before further processing. In our paper, we are interested in selecting a suitable method of offline rotor diagnostics of an asynchronous motor that would be effective for these needs. In the first step, the selection of the method and its integration into the overall manufacturing process is carried out. The arrangement of the sensors and their calibration is then simulated on a 2D Finite Element Model of the rotor. The proposed offline measurement procedures and technologies are finally validated by testing measurements on a rotor that simulates the most frequently occurring faults. A test system is also developed that provides the operator continuous information about the running rotor measurements and makes it easier to evaluate the quality of the cast rotor by means of graphical visualization of the faults.

Magnetic fluid hyperthermia has gained much attention in recent years due to its potential in cancer treatment. Magnetic fluid is a colloidal liquid made of nanoscale magnetic particles suspended in a carrier fluid. The properties of a commercial magnetic fluid consisting of maghemite (γ-Fe2O3) particles suspended in mineral oil were used in the scope of our research. The paper deals with a novel approach to the development of a magnetic fluid FEM model of a laboratory setup, with consideration of the electromagnetic steady state and thermal transient calculation soft coupling. Also, adjustment of the mathematical model was added in such a way that it enables a link between the magnetic and thermal calculations in commercial software. The effective anisotropy’s influence on the calculations is considered. The simulation was done for different magnetic field parameters. The initial temperature was also varied so that a direct comparison could be made between the simulation and the measurements. A good indicator of the accuracy of the simulation are the SAR values. The relative differences in SAR values were in the range from 4.2–24.9%. Such a model can be used for assessing the heating performance of a magnetic fluid with selected parameters. It can also be used to search for the optimal parameters required to design an optimal magnetic fluid.

The paper presents research to verify the effectiveness of nine selected material models of elastomeric materials based on uniaxial tension test. Basing on the cyclic uniaxial tension test of elastomers sample, the stress-strain characteristic for the 18th load cycle was prepared. On the basis of the obtained characteristic, the values of material constants were calculated for the studied models (Neo-Hookean, Mooney with two and three constants, Signorini, Yeoh, Ogden, Arruda-Boyce, Gent and Marlow) and simulation of tensile, upsetting and bending processes was performed with the usage of the software MARC/Mentat. The effectiveness of the selected models was determined based on a comparison of results obtained in the experimental tensile test, upsetting test and bending test of an elastomeric samples with the results of numerical FEM calculations for each models. The research has shown that, for modeling of the elastomeric cylinder upsetting in the range of deformation of 62%, the best results with the comparison of the experiment were obtained by using the Yeoh model. In the bending process none of the analyzed models indicate a high convergence of results from an experiment. Analyzing the characteristics of the experimental and numerical tensile test it can be seen that in the entire range of punch movement (0 to 55 mm), models Signorini, Marlow, Ogden(N3) and Mooney(3) give the best results.

The paper investigates the general buckling of an axially loaded column using the finite element method with different slenderness ratios of axes x-x and z-z. The paper deals with three different modes of buckling. The conducted numerical experiments have suggested correction factors and appropriate buckling modes of the built-up columns. The obtained modelling results were compared with data on analytical calculations made according to Lithuanian national codes STR and Eurocode 3. The FEM analysis of the builtup column has showed that both codes (STR and EC3) are giving safe enough results for a considered type of conditions for column support. Santrauka Straipsnyje nagrinėjami plieninių spragotųjų kolonų elgsenos ypatumai, atsižvelgiant į skirtingas STR 2.05.08:2005 ir EC3-1-1 metodikas. Didžiausią susidomėjimą kelia faktas, kad, taikant EC3 metodiką, nėra nagrinėjama spragotosios kolonos kluptis apie didesnio standumo x-x ašį (1 pav.). Naudojantis turima ir kitų autorių patirtimi apžvelgta spragotosios centriškai gniuždomos kolonos elgsena, siekiant nustatyti jos klumpamąją galią, kai kolonos liauniai yra didesnio standumo, o mažesnio standumo plokštumoje yra skirtingi. Nagrinėtos trys skaičiuotinės situacijos: 1) spragotoji kolona idealiai tiesi, o abi kolonos juostos perima vienodas ašines jėgas (STR2.05.08:2005 prielaida); 2) spragotoji kolona tiesi, bet kolonos juostos ašinės jėgos padidintos dėl pradinio kolonos nuokrypio nuo tiesiosios ašies ir papildomo lenkiamojo momento (EC 3-1-1 prielaida); 3) kolona su pradiniu nuokrypiu, o ašinės juostų apkrovos yra vienodos (EC3-1-1 prielaida). Pradiniai modeliavimo duomenys pateikti 1 lentelėje. Kolonos juostos modeliuotos plokštelės tipo baigtinais elementais, o tinklelio strypai – strypiniais. Kolonos įtvirtinimo sąlygos ir skaičiuojamieji ilgiai pateikti 2 pav. Atlikus skaitinį modeliavimą gauti kolonos bendrojo klupumo pataisos koeficientai (2 lentelė) ir kolonos klupumo pavidalai (5 ir 6 pav.). Kaip matyti iš 7 pav., skaitinio modeliavimo rezultatai 2-uoju ir 3-iuoju atvejais yra skirtingi, nors turėtų būti vienodi modeliuojant pagal EC3 prielaidas. Galima teigti, kad antruoju atveju (spragotoji kolona tiesi, bet kolonos juostų ašinės jėgos padidintos dėl pradinio kolonos nuokrypio ir papildomo lenkiamojo momento) gaunami tikslesni rezultatai. Skirtumas tarp 1-ojo (STR) ir 2-ojo atvejo (EC3) nėra didelis; nuo 22% iki 30% (9 pav.). Kai kolonos liaunis λ x=35, pataisos koeficientas yra 2,11, naudojant EC3, ir 1,78, taikant STR metodą. Nedidelio liaunio kolonų bendrojo klupumo atsarga, naudojant EC3 prielaidas, yra 30% didesnė nei taikant STR metodą. Kai liaunis λ x=200, pataisos koeficientas yra 1,16 pagal EC3 ir 1,38 pagal STR metodiką. Liaunų kolonų klupumo atsarga pagal EC3 yra 23% mažesnė nei pagal STR metodą. 1-uoju ir 2-uoju atveju (1 lentelė) kolonų kluptis įvyko iš plokstumos apie z-z ašį (6 pav.), nes šioje plokštumoje kolonų liaunis didesnis. Kolonų klupumo pavidalas atitinka analitinius skaičiavimus tiek STR, tiek EC3 metodu. 3-uoju ir 4-uoju atveju (1 lentelė) kolonos klupo apie x-x ašį (5 pav.), nes šioje plokštumoje kolonos liaunis gerokai didesnis (2 pav.). Klupumo pavidalas atitinka analitinius skaičiavimus pagal STR metodiką. Taikant EC3 metodiką kolona turėjo klupti iš plokštumos, t. y. apie z-z ašį. Šis klupumo pavidalas taip pat buvo pasiektas, tačiau vėliau (žr. pataisos koeficientus 2 lentelėje.). Taip yra todėl, kad pagal EC3 metodiką tiesiog nereikalauja visos kolonos pastovumo tikrinti apie x-x ašį. Atlikus skaitinius modeliavimus galima teigti, kad abu metodai STR ir EC3 yra saugūs (pataisos koeficientai visada didesni už vienetą) duotomis kolonos galų įtvirtinimo sąlygomis. Tik mažo liaunio kolonų λx≤80 didesnė atsarga gauta STR metodu, o liaunų kolonų, kai λx>80 didesnė atsarga gauta taikant EC3 metodą. Reikšminiai žodžiai: plieninė spragotoji kolona, klupumas, bendrojo pastovumo skaičiavimas, modeliavimas baigtiniais elementais

Capacitive sensors are widely used in industrial applications, such as CNC machine tools, where reliable positioning in the micrometer range with nanometer accuracy is required. Hence, these sensors are operated in harsh industrial environments. The accuracy of these sensors is mainly limited by slope errors and nonlinearities. In practice, the required accuracy of these sensors is achieved by a calibration against a metrological high-quality reference such as interferometric displacement measurement systems. This usually involves the use of high-order polynomials as calibration functions based on empirical data. In metrology, this is only the second-best approach and has disadvantages in terms of stability over the measurement range of the instrument. In addition, the validity of these empirical calibrations over time is questionable, and the associated uncertainty can only be roughly estimated. This makes regular recalibration of such sensors at short intervals mandatory to ensure the reliability of the displacement measurement. In this paper, we report on our investigations of the different parameters that affect the accuracy of capacitive sensors. Since the capacitance of these sensors results from the electric fields that build up between the electrodes, these field lines are calculated using FEM simulation models for typical commercial sensors. In the following the influence of various geometric parameters such as edge radius, guard ring size and shape, or thickness of the electrodes are individually analyzed according to their impact on the accuracy of these sensors. Based on these simulations, the deviations of the capacitance as they arise for real detector geometries can then be compared with idealized, de facto unrealizable parallel plate capacitors. This methodology allows overall uncertainty of capacitive sensors to be decomposed into their individual components and sorted in terms of their contribution to the uncertainty budget. The individual FEM-based analysis then enables a systematic analysis of the sources of uncertainty and, thus, reveals possibilities to improve manufacturing processes for capacitive sensors, to put these sensors on a solid metrological basis, and to improve the performance of these displacement measurement systems in the long run, i.e., to provide better sensors for the application.

In recent years, the interest in monitoring the operating conditions of freight wagons has grown significantly to improve the safety of railway vehicles. The railway research group of the Politecnico di Torino has been working for years on the development of solutions to effectively monitor the operating conditions of passenger and freight rail vehicles. As part of the national Cluster ITS Italy 2020 project funded by Italian ministry of education, university and research (MIUR), the Politecnico di Torino has collected a considerable amount of data thanks to the wired and wireless prototypes developed. The data obtained are used in this paper for the validation and calibration of a finite element (FE) model that simulates the temperature variation of a cast iron brake block due to braking operations of an intermodal freight wagon. The developed model can be a useful tool to predict the temperature at the wheel–shoe interface as a function of the current operating conditions since a direct measurement is not easy to perform.

This paper analyses three components of total cutting force and chip shape changes when finish turning 17-4 PH (precipitation hardening) stainless steel. A Finite Element Method (FEM) simulation of cutting forces was also performed using the Johnson–Cook constitutive model. The results were compared with those obtained from experimental studies. Variable feeds of 0.05–0.4 mm/rev and depth of cut of 0.2–1.2 mm with a cutting speed of 220 m/min were used. The studies were carried out under dry and wet cooling conditions and with the use of minimum quantity lubrication (MQL). This research was realized based on the Parameter Space Investigation (PSI) method. Statistical analysis of the obtained results was carried out using Statistica-13 software. It was found that the cutting force Fc and feed force Ff depend on the depth of cut and feed, and the passive force Fp depends mainly on the feed. Compared to dry cutting conditions, a reduction of 43% and 39% of the cutting force Fc was achieved for wet machining and MQL machining, respectively. Regardless of the cooling conditions, a favorable chip shape was registered for ap = 1–1.1 mm and f = 0.25–0.3 mm/rev. Compared to the experimental studies, the FEM simulation showed differences of ~13% for the cutting force Fc and of ~36% for the feed force Ff.

Defects generated during the casting process of steel can be reduced by forming processes such as hot rolling. During these processes the effective strain, the temperature, the stress state and the alternation of the forming direction all influence the defect evolution. Analytical or numerical models are available in the literature to predict the defect evolution. However, experiments have to be carried out to identify the parameters of these models. Thus, the quality of the identification depends on the representativeness of the experiments with respect to the industrial forming process. This paper proposes a methodology to design reduced scale experiments with an improved level of representativeness. This methodology consists first in the identification of the thermomechanical parameters driving the defect evolution and the quantification of these parameters in the industrial process by FEM simulation. These last results are then utilised as criteria for the representative experiment design. In this work the methodology is applied to the rolling of bars. The representative experiment consists of successive forming operations of a cylindrical sample between shaped anvils reproducing the roll shape at a 1:10 scale. A validation is finally achieved by reproducing qualitative results concerning the evolution of voids in the vicinity of hard inclusions.

Deformation softening is quite often observed during hot working of different alloys. Steels, aluminium, titanium or nickel alloys can demonstrate a decrease in flow stress under active deformation at constant temperatures and strain rates. Though the background microstructural mechanisms as well as the softening rates can be quite different, the treatment of such processes requires special attention. Deformation softening can cause significant non-uniformity of the metal flow resulting in flow localization, formation of shear bands and variation of the microstructure across the workpiece. This paper is devoted to the investigation of the specific issues which arise in this respect in FEM simulation of processes involving softening. The possible role of softening in shear band formation is studied using numerical simulation and physical modelling. The effect of the softening rate on the probability of flow localization is discussed. The interplay of deformation softening with the stain rate and temperature sensitivity is demonstrated using as an example the simulation of Equal Channel Angular Pressing (ECAP). An approach to account for the deformation softening in FEM simulations via process modelling of the microstructure refinement is proposed.

Integral abutment bridges are becoming rather common, due to the durability problems of bearings and expansion joints. At the same time, among short- and medium-span bridges, multi-beam steel-concrete composite deck with hot-rolled girder is an economical and interesting alternative to traditional pre-stressed concrete solutions. The two concepts can be linked together to design integral steel-concrete composite bridges with the benefits of two typologies. The most critical aspect for these bridges is usually the joints between deck and piers or abutments. In this paper, an innovative beam-to-pier joint is proposed and a theoretical and experimental study is introduced and discussed. The analyzed connection is aimed at combining general ease of construction with a highly simplified assembly procedure and a good transmission of hogging and sagging moment at the supports in continuous beams. For this purpose, the traditional shear studs, used at the interface between steel beam and upper concrete slab, are also used at the ends of steel profiles welded horizontally to the end plates. To better understand the behaviour of this kind of joints and the roles played by different components, three large-scale specimens were tested and an FE model was implemented. The theoretical and experimental results confirmed the potential of the proposed connection for practical applications and indicated the way to improve its structural behaviour.

Resin transfer molding (RTM) technologies are widely used in automotive, marine, and aerospace applications. The need to evaluate the impact of design and production critical choices, also in terms of final costs, leads to the wider use of numerical simulation in the preliminary phase of component development. The main issue for accurate RTM analysis is the reliable characterization of the involved materials. The aim of this paper is to present a validated methodology for material characterization to be implemented and introduce data elaboration in the ESI PAM-RTM software. Experimental campaigns for reinforcement permeabilities and resin viscosity measurement are presented and discussed. Finally, the obtained data are implemented in the software and then compared to experimental results in order to validate the described methodology.

Vibration problems of the building structures caused by technical seismicity are becoming increasingly topical. The aim of this paper is to show FEM simulation of the spreading wave impact, which causes vibration system consisting of subsoil-structure interaction in microtremor. The results of the experiment together with this theoretical analysis and FEM simulation appear to be effective application for engineering experience. They are also used in assessing and predicting the vibration effects induced by technical seismicity due to traffic. [1].

In this paper an investigation on the fault tolerance capability of the five-phase permanent magnet synchronous generator is presented. The electric machine, which has lap stator winding and surface permanent magnets, has been designed for islanded-use purposes. The study takes into consideration the open-circuit type faults. It was analyzed the operation under healthy, one-phase open-circuited and two-phase open-circuited (adjacent and non-adjacent) conditions respectively. The results derive from FEM-based simulations and experimental tests.

This paper describes about the intensity of stress concentration, and the maximum stress component occurred on the inside liner of a corrugated fiberboard during a rotary creasing process. Three dimensional finite-element analysis, based on the combination of orthotropic-elastic liners and Ring Crush Test based medium, was carried out by varying mechanical conditions such as the working diameter of the main-creaser, the boundary constraint of lateral tensile state and the misalignment of the biting position with an apex of corrugated medium. The simulated stress distribution and deformation shape of inside liner explained about a few experimental features, such as the failure occurrences on the inside liner.

This paper is concerned with a physical model of an interdigitated sensor working in a frequency range from 100 Hz to 10 MHz. A theoretical approach is proposed to optimize the use of the sensor for bioimpedance spectroscopy. The correlation between design parameters and frequency behavior in coplanar impedance sensors are described. CoventorWare® software was used to model the biological medium loaded interdigital sensor in three dimensions to measure its electrical impedance. Complete system simulation by a finite element method (FEM) was used for sensor sensitivity optimization. The influence of geometrical parameters (number of fingers, width of the electrodes) on the impedance spectroscopy of the biological medium was studied. The simulation results are in agreement with the theoretical equations of optimization. Thus, it is possible to design a priori such sensor by taking into account the biological medium of interest that will load the sensor.

Determination of flow curves of metals, which are indispensable for numerical simulations of forming processes, is often limited to tensile or compression tests. However in some cases the shear stress-strain behavior of materials needs to be determined as well. In the paper digital analyses of shear-hat test at room temperature were performed for various steels, AlMg3 aluminium alloy and AZ80 magnesium alloy. Comparative analyses of process parameters and specimen geometry as a function of tool displacement were performed for better understanding of the testing procedure.

In this paper, water quenching of large ingots was simulated using FORGE NxT 1.1® Finite Element code. Simulations were carried out for as-forged medium-carbon low-alloy steel. A novel method is proposed to simulate the different parts of a large size forged block with different chemical compositions and grain sizes using the multiple materials method. The effects of macrosegregation, grain size variation and cooling rate on phase distribution through the volume of the forged block were investigated. The delay in transformation kinetics, which is due to the effect of grain size variation and carbon content, was analyzed. Results show that macrosegregation and grain size variations significantly influence transformation start points and the volume fraction of phases that are present in each location of the forged ingot. The proposed prediction method was validated using high-resolution dilatometry experiments and X-ray diffraction measurements to evaluate accurately the volume fraction of martensite, bainite and the percentage of retained austenite for each condition.