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Featured Application: The developed surrogate model-based parameter tuning method of the simulated annealing algorithm is suitable for solving not only numerical simulation optimization problems but also other computationally intensive model-driven optimizations. A design engineer has to deal with increasingly complex design tasks on a daily basis, for which the available design time is shrinking. Market competitiveness can be improved by using optimization if the design process can be automated. If there is limited information about the behavior of the objective function, global search methods such as simulated annealing (SA) should be used. This algorithm requires the selection of a number of parameters based on the task. A procedure for reducing the time spent on tuning the SA algorithm for computationally expensive, simulation-driven optimization tasks was developed. The applicability of the method was demonstrated by solving a shape optimization problem of a rubber bumper built into air spring structures of lorries. Due to the time-consuming objective function call, a support vector regression (SVR) surrogate model was used to test the performance of the optimization algorithm. To perform the SVR training, samples were taken using the maximin Latin hypercube design. The SA algorithm with an adaptive search space and different cooling schedules was implemented. Subsequently, the SA parameters were fine-tuned using the trained SVR surrogate model. An optimal design was found using the adapted SA algorithm with negligible error from a technical aspect. [ABSTRACT FROM AUTHOR]

Thanks to the great efforts of our reviewers, I Applied Sciences i was able to maintain its standards for the high quality of its published papers. Rigorous peer-reviews are the basis of high-quality academic publishing. [Extracted from the article]

Featured Application: In the design of engineering polymeric products, the detailed finite element investigation is indispensable. In most cases, polymeric products are investigated with multilinear material models over the entire stress-strain range. The definition of these material models requires material parameters, which must be obtained through time and cost demanding laboratory measurements. For some applications, such as quasi-static loading, it would be sufficient to use a linear elastic material model, the material constants of which can be obtained quickly. This article can help designers to apply the right material model as the linear elastic material model can be used until the 0.96% strain value in the case of the PA6 material with sufficient accuracy. One of the most critical issues during polymer finite element simulations is the selection of the proper material models. The widely used and accepted multilinear material models require load case-specific material tests, which are time and cost demanding. Data for these characteristics must be acquired by standardized measurements. On the other hand, the parameters required to create a linear elastic material model in most cases are easy to obtain, and the establishment of the model is a shorter process. This research is aimed to provide information to engineers about the possibility of modeling the nonlinear elastic materials by using linear elastic material models and about the limits of such models. To create the most accurate material models, laboratory measurements were performed on polyamide (PA6) material, which is a widely used raw material in the industry. Test specimens were manufactured to obtain material constants according to the ISO 527-2 standard, and for validating the effectiveness of the applied material models, three different tensile specimens were created, which were tested under quasi-static loading in the elastic region. A comprehensive finite element investigation was performed, and the numerical results were then compared to laboratory measurements using the GOM Aramis digital image correlation (DIC) system. By comparing the optically measured strain data to the numerical results, it was determined that the nonlinear elastic materials can be modeled using linear elastic models in a well identifiable strain range with sufficient accuracy. [ABSTRACT FROM AUTHOR]

Previously, a dynamic model and a simulation program for series wound DC motors (SWDCM) were developed in MATLAB/Simulink for modelling them in electric vehicles and mechatronic systems. The electromagnetic characteristics of the motor (electric resistances, dynamic inductances), which serve as input parameters of the program, were also measured. Additionally, locked rotor response measurements were performed to test the accuracy of the measured electromagnetic characteristics. This paper presents the experimental procedure and the results of dynamics test measurements that were performed on the same motor, including the procedure for the determination of the necessary input dynamic parameters for the simulation. While the motor spins up from rest, the intensity of the electric current and the angular speed of the rotor are measured. Finally, the simulation and dynamic test results are compared to check the proper operation of the simulation program. [ABSTRACT FROM AUTHOR]

In rubber bumper design, the most important mechanical property of the product is the force–displacement curve under compression and its fulfillment requires an iterative design method. Design engineers can handle this task with the modification of the product shape, which can be solved with several optimization methods if the parameterization of the design process is determined. The numerical method is a good way to evaluate the working characteristics of the rubber product; furthermore, automation of the whole process is feasible with the use of Visual Basic for Application. An axisymmetric finite element model of a rubber bumper was built with the use of a calibrated two-term Mooney–Rivlin material model. A two-dimensional shape optimization problem was introduced where the objective function was determined as the difference between the initial and the optimum characteristics. Our goal was to integrate a surrogate model-based parameter selection of local search algorithms for the optimization process. As a metamodeling technique, cubic support vector regression was selected and seemed to be suitable to accurately predict the nonlinear objective function. The novel optimization procedure which applied the support vector regression model in the parameter selection process of the stochastic search algorithm proved to be an efficient method to find the global optimum of the investigated problem. [ABSTRACT FROM AUTHOR]

Fault diagnosis of bearings is essential in manufacturing to increase quality. Traditionally, fault diagnosis of tapered roller element bearings is performed by signal processing methods, which handle the nonstationary behaviour of the signal. The wavelet transform is an efficient tool for analysing the vibration signal of the bearings because it can detect the sudden changes and transient impulses in the signal caused by faults in the bearing elements. In this article, manufacturing faults on the outer ring of tapered roller bearings due to the grinding process in manufacturing are investigated. Nine different real values wavelets (Symlet-2, Symlet-5, Symlet-8, db02, db06, db10, db14, Meyer, and Morlet) are compared according to the Energy-to-Shannon-Entropy ratio criteria, and which is efficient for detecting the manufacturing faults is determined. Finally, experiments are carried out on a test rig for determining the geometrical size of the manufacturing faults with all wavelets directly from the vibration signature the result of db02, Symlet-5, and Morlet wavelets are presented. When modelling the bearing structure as an under-damped second-order mass-spring-damper mechanical system, its unit impulse response function is compared to the wavelets on the basis of their Energy-to-Shannon-Entropy ratio to determine the fault size from the vibration signal. The proposed technique has been successfully implemented for measuring defect widths. The maximum deviation in result has been found to be 4.12 % for the defect width which was verified with image analysis methods using an optical microscope and contact measurement. [ABSTRACT FROM AUTHOR]

Wear and surface microgeometry aspects of fiber-reinforced hybrid composite dry friction clutch facings are revealed in a novel way: after different, real life automotive tests during their lifetime. This study examines and reveals the tribological response of friction material surfaces to real life application conditions with two different facing diameters and in two directions. Along the increasing activation energy scale, wear values increased according to two different trends, sorting tests into two main groups, namely 'clutch killer' and 'moderate'. Wear results also highlighted the influence of mileage and test conditions, with clutch killer tests also creating considerable wear-more than 0.1 mm-at inner diameters: 1% higher wear was generated by 90% higher mileage; another 1% increment could be caused by insufficient cooling time or test bench-specific conditions. Surface roughness values trends varied accordingly with exceptions revealing effects of facing size, friction diameter and directions and test conditions: small (S) facings produced significantly decreased Rmax roughness, while large (L) and medium (M) size facings had increased roughness values; Rmax results showed the highest deviations among roughness values in radial direction; tests run with trailer and among city conditions resulted in more than 2% thickness loss and a 40–50% roughness decrease. [ABSTRACT FROM AUTHOR]

In addition to the examination of electric power from local renewables, this study has sought the answer to the question of what proportion of vehicles are fueled by environmentally friendly energy saving technologies in the vehicle fleets of Hungarian settlements. Further, the study attempts to shed light on the self-sufficiency of Hungarian settlements with respect to the electricity and transport segments. In our assessments, the performance of small-scale household power plants (SSHPPs) utilizing local renewable energy sources, and small-scale power plants with installed capacities under 0.5 MW, was taken into account, as were the proportions of vehicles operating with partly or completely clean energy sources in the vehicle fleets of the individual settlements. Finally, the composition of the vehicle fleet has been examined in the light of the quantities of renewable electricity generated in the individual settlements, in order to consider whether these settlements are capable of covering the energy needs of their vehicle stocks from local sources. In the light of the results, the changes generated by the incentives and investments introduced over the past ten years can be established and subsequently, the energy policy needs in the future can be assessed. Our study has incorporated energy geography and settlement geography aspects. [ABSTRACT FROM AUTHOR]

The wear behaviour of two martensitic and one multiphase steel targeted for abrasion and erosion applications in agriculture and mining industry were investigated in three abrasive test systems with different complexity. Scratch tests were performed with different indenter radii, shapes, and loads. The material behaviour was also investigated in multi-asperity contact systems. Pin-on-disc tests were performed with various loads and abrasive particles, as well as abrasive slurry-pot tests with different sliding velocities, distances, and impact angles of the abrasive media were performed. Comparing the test systems, the tested materials ranked similarly based on their wear performance, however, in each configuration, the dominant variable of the wear mechanism differed. The significance and contributions of test paramecenterters, the material's mechanical properties (H, σ M , σ Y , E, ε M , ε B , W, σ c , E c ) and the dimensionless numbers formed from them were investigated on the wear behaviour and the surface deformation. Correlation between parameters was established by multiple linear regression models. The sensitivity of the tested materials to abrasion was evaluated taking into account the wide range of influencing parameters. [ABSTRACT FROM AUTHOR]

Fiber-reinforced hybrid composites are the most commonly used dry-friction materials in the automotive industry. On the other hand, the great variety of components utilized these days in such material systems often requires identification investigations for a complex characterization. The development history of clutch materials was reviewed, highlighting and understanding the milestones and efforts leading to the creation of these materials. Investigations were performed to determine mechanical stiffness matrix parameters and thermal properties of a woven fiber yarn (glass fiber with aromatic polyamide, copper, and poly-acrylic-nitrile (PAN) reinforced friction material, revealing and solving challenges faced during identification efforts. This study grants an effective reference and a novel guidance for material identification methods for similar complex materials, and the results provide input parameters for thermomechanical simulation contact model development, which will cover friction material lifetime effects on dry clutch tribology in a future study. [ABSTRACT FROM AUTHOR]

The present paper concentrates on the toughness and the degree of crystallinity of the magnesium-catalyzed polyamide 6 rods cast in different diametres, which are commonly used for gear manufacturing. Its toughness cannot be regarded as a constant feature due to the casting technology. The mechanical properties of the semi-finished products are sensitive to the manufactured dimension, e.g., cast diameter, which are investigated by the Charpy impact test and tensile impact test. It is generally accepted that the impact strength and tensile-impact strength correlate with the degree of crystallinity beside many other material's feature. Crystallinity is evaluated by Differential Scanning Calorimetry. The aim of this study is to determine the relationship between toughness and crystallinity of the magnesium-catalyzed cast PA6 rods with different diameters. For the research cast rods between 40 and 300 mm diameter were selected in seven-dimensional steps. Based on the results, it was found that the toughness depends strongly on the diameter size. Furthermore, it is proved that the crystallinity explains 62.3% of the variation of the Charpy's impact strengths, while the tensile impact method was not suitable to detect the difference between the test samples. [ABSTRACT FROM AUTHOR]