Engineering Transactions (formerly Rozprawy Inżynierskie) is a refereed international journal founded in 1952. The journal promotes research and practice in engineering science and provides a forum for interdisciplinary publications combining mechanics with: Material science, Mechatronics, Biomechanics and Biotechnologies, Environmental science, Photonics, Information technologies, Other engineering applications. The journal publishes original papers covering a broad area of research activities including: Experimental and hybrid techniques, Analytical and numerical approaches. Review articles and special issues are also welcome. Following long tradition, all articles are peer reviewed and our expert referees ensure that the papers accepted for publication comply with high scientific standards. Engineering Transactions is a quarterly journal intended to be interesting and useful for the researchers and practitioners in academic and industrial communities. Occasionally, special issues of the journal may be devoted to publication of all or selected papers presented at international conferences or other scientific meetings. However, all papers intended for such an issue are subjected to the usual reviewing and acceptance procedure.
Institute of Fundamental Technological Research Polish Academy of Sciences
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Challenges of Corrosion, Wear, Erosion, and Abrasion in Hydropower Plants: Materials, Modeling, and Mitigation Strategies
The chemical, food processing, hydropower, thermal power, and oil industries are among the sectors that frequently face the problems of erosion, abrasion, and corrosion. Pipelines, elbows, reducers, separators, tees, and seals are among the hydraulic devices and pipeline components that are impacted by these difficulties. Silt erosion in turbines and related parts is a major issue in hydropower plants, particularly in Indian hydropower plants where rivers contain hard elements like feldspar, quartz, and other minerals. Remarkably, more than half of the quartz in the silt causes problems in turbines, including sediment erosion, leaks, and secondary flow disturbances. Hydropower plants' total efficiency is ultimately jeopardized by these issues. This paper aims to support scholars and researchers by highlighting the following topics: (i) component failures in impulse and response turbines used in hydropower projects; (ii) different turbine materials and their properties; and (iii) a comparison of several thermal spraying techniques for turbine materials along with numerous numerical models of erosion and abrasion informed by silt characteristics, material properties, and flow phenomena in different hydro-turbines. The study also discusses modeling, pilot plant loops, wear mechanisms, and protective techniques aimed at mitigating wear and safeguarding hydro turbines.
Copyright (c) 2025 Harvinder Singh https://creativecommons.org/licenses/by/4.0
Modeling Defect Detection in 3D-Printed Structures Using Ultrasonic Guided Waves
Carbon fiber-reinforced thermoplastic composites are widely utilized in 3D printing via the fused filament fabrication (FFF) process. However, defects within printed components can compromise their performance. This study investigates the application of ultrasonic non-destructive testing (NDT) techniques for structures manufactured through FFF. Common printing defects, such as weak interlayer bonding, surface imperfections, and internal cracks, are simulated using a finite element (FE) model. The model analyzes how guided ultrasonic waves interact with these defects. The proposed methodology incorporates digital transducer control and evaluates the energy distribution across incident, reflected, and transmitted wave modes. Three representative defect types are modeled, and the approach is applied to two structural geometries: plates and pipes. The study investigates the correlation between defect size and the behavior of energy reflection and transmission. A signal processing approach is applied, using transducers positioned symmetrically along the wave propagation axis to detect mode conversion and analyze wave reflections and transmissions. The phenomenon of mode conversion is analyzed in detail, and the results are validated by ensuring energy balance consistency.
Copyright (c) 2025 Ismaine Zitouni, Hassan Rhimini, Abdelkerim Chouaf https://creativecommons.org/licenses/by/4.0
Collision Integral for Non-Equilibrium Distributions of 1D Bosons with Non-Linear Dispersions
In order to understand transport phenomena in a quasi-classical regime the Boltzmann transport equation (BTE) is one of the most frequently used tools. Therein, the key quantity is a collision integral – the quantity that encapsulates the properties of the medium under consideration. Usually the result of this integral is approximated by one single parameter, the relaxation time. However it leaves one wondering if such situation is sufficient: for instance, if the dispersion of bosons is non-linear then what will be the influence of this non-linearity on the BTE. Here we give a fully analytic solution of the collisions’ integral for 1D bosonic gases with non-linear dispersion and far out of equilibrium. Our analytic result is given in terms of the Lerch transcendent function and it has been obtained for the case of two sub-systems (one dragging another), by taking a maximum-entropy displaced Bose–Einstein ansatz for their distributions. Currently, there are numerous experiments performed far away from equilibrium, where distributions are massively shifted and our result will serve as a main building block to derive distributions of bosons, and later linear and nonlinear transport coefficients, in such regimes.
Copyright (c) 2025 Piotr Chudzinski, Wieslaw Larecki https://creativecommons.org/licenses/by/4.0
Global buckling of a thin-walled T-frame with consideration of the shear effect
The work concerns the global elastic buckling problem of a thin-walled T-frame with consideration of the shear effect. A novel approach was used to account for this effect namely the non-linear shear deformation theory which gives as a result the shear deformation function describing the behaviour of the beam cross-section. This thin-walled T-frame consists of horizontal beam and vertical column made of the same standard H-beams. The shape of this standard H-beam and the dimensionless deformation function of the plane cross-section, being the result of the shear effect, are analytical described. The buckling problem of the frame is analytically formulated and solved. The critical loads of exemplary beams are analytically determined. Moreover, a numerical FEM model of the frame is elaborated and the critical loads of exemplary frames are determined. Consequently, the research results obtained by both methods are compared and the advantages of the proposed approach is discussed.
Copyright (c) 2025 Krzysztof Magnucki, Paweł Jasion https://creativecommons.org/licenses/by/4.0
Analytical Approach and Shooting Method Solution of Nonlocal Eringen Elasticity Problem of Nanorods
The aim of this paper is to study the postbuckling behaviors of the nanorods combined with the small scale effects. In this paper, buckling of a nanorod column subjected to tip load is investigated. The nanorod is on a clamped support at one end, while the other end is simply-supported subjected to axial compression. At this end, the nanorod is movable only in a horizontal direction. The governing differential equation describing the behavior of the nanorod is developed by the moment–curvature relationship in analogy with the classical Euler–Bernoulli beam theory together with the equilibrium equations, including the effects of nonlocal elasticity as well as corresponding boundary conditions. The numerical shooting methods are derived and employed to solve the differential equations in this problem. The results, including nonlocal elasticity, reveal that nanorods have decreased structural stiffness and show the significant effect of geometrical parameters on the stability of buckled nanorods, emphasizing the importance of accounting for their interaction in the design of nanostructural systems.
Copyright (c) 2025 Aleksandra Manecka-Padaż, Ewa Eliza Rożko, Zdzisław Nowak , Piotr Chudzinski https://creativecommons.org/licenses/by/4.0
Non-linear analysis of wrinkling phenomena in sandwich beams with soft core
The work is devoted to the local stability analysis of sandwich beams with light core. A linear as well as non-linear numerical analysis is carried out with the use of the finite element method (FEM). Both material and geometrical nonlinearities are taken into account. The goal of the investigation is to examine the influence of the material model on the post-buckling behaviour of a sandwich beam especially on the formation and developing of wrinkles on the compressed face. A pure bending condition is considered for the beam simply supported at both ends. The results for materials of theoretical properties are presented as well as for data from experiments on aluminium sandwich beams. From the results it is seen that the linear analysis of wrinkling phenomenon for non-linear materials gives overestimated results and does not predict correctly the buckling shape.
Copyright (c) 2025 Paweł Jasion, Iwona Małgorzata Wstawska, Kamil Kołodziński https://creativecommons.org/licenses/by/4.0
Sustainable Natural and Synthetic fibers with Epoxy Composites of Mechanical Characterization and One-Way ANOVA Statistical Analysis
It is now well recognized that the combination of natural and synthetic fibers in synergistic fiber composite materials can greatly broaden their applications in engineering and technology. Natural-fibers are gaining more consciousness because of their biodegradability, easy availability, durability, and resistance to corrosion, positioning them as an eco-friendly substitute for conventional materials. At the same time, fiber-reinforced composites are increasingly replacing metals in multiple sectors owing to their cost-effectiveness and energy efficiency. Epoxy resin-based hybrid composites were prepared by incorporating glass, hemp and ramie fibers through the hand layup approch. Laminates were characterized for tensile, flexural, impact, and hardness performance using ASTM standard methods. The greatest tensile strength, 73.10 MPa, was achieved in the glass/ramie fiber composite. The hybrid composites comprising glass, ramie, and hemp fibers exhibited enhanced flexural behavior of 18.22 MPa, impact resistance of 142.45 kJ/m². Among the tested configurations, the glass–ramie fiber composite recorded the highest hardness value of 27.73 HV. Overall, the determination highlight that glass-ramie-hemp fiber-mixed epoxy composite materials can serve as prospective eco-friendly substitute to conventional synthetic composites in non-structural applications, such as automotive interiors, by offering a balance of good mechanical performance and sustainability.
Copyright (c) 2025 Sadashiva Kemparaju, Bhanu Prathap Rangaswamy, Balaji Javaraiah, Shwetha Mahadev, Rathika Murugan, Tarakeshwar Jane https://creativecommons.org/licenses/by/4.0
Preface to a selection of papers presented at the SiMRTRANS Scientific and Technical Conference: “Innovative Solutions in Transport”, which took place at the Warsaw University of Technology, Faculty of Automotive and Construction Machinery Engineering, on September 19, 2024.
SIMRTRANS: Innovative solutions in means of transport
Copyright (c) 2025 Dariusz WIĘCKOWSKI https://creativecommons.org/licenses/by/4.0
Simulation Study of Direct-Shear Test on FRP-to-Concrete Bonded Joints by Means of XFEM
A proper numerical modelling of FRP-to-concrete bonded joints is crucial for determining their strength. In this paper the results of numerical analyses performed by XFEM on such joints in direct-shear test are presented. The study uses a fracture mechanics approach based on the traction-separation law for definition the FRP-concrete interface. It includes definition of damage initiation as well as damage evolution, taking advantage of the fracture energy for plain concrete as well as the interfacial fracture energy of analysed joint. The interfacial fracture energy of bonded joint is essential for accurately describing the local bond–slip behaviour. The numerical study is aimed to investigate the sensitivity of direct-shear test models to magnitude of fracture energies, material strengths, type of adhesive and the length of FRP-to-concrete joint. Some general results and conclusions of performed analyses are presented.
Copyright (c) 2025 Iwona Jankowiak https://creativecommons.org/licenses/by/4.0
Caustics Formation by a Spherical Reflector – Geometric and Wave Field Analysis with Applications in Room Acoustics and Radio Astronomy
Based on the principles of geometrical optics, an analytical description of caustics generated in a spherical mirror is presented. The formation of caustics in a wave field is studied using acoustic and electromagnetic waves as an example. Symmetry of equations describing energy relations in acoustics and electromagnetism is shown. The presence of caustics in natural phenomena is demonstrated, as well as their manifestation in architectural acoustics and astronomy. It is explained why in the sound field in existing halls, rather than the entire caustics, only their cusp is observed, which is perceived as a blurred area with an increased sound level accompanied by unusual values of acoustic room parameters. The influence of caustics on the efficiency of spherical and parabolic antennas used in radio astronomy is discussed.
Copyright (c) 2025 Andrzej Kulowski https://creativecommons.org/licenses/by/4.0
Numerical modeling of aluminum alloy AW5083using large strain thermo-elasto-plasticity
This paper deals with the constitutive modeling and finite element simulations of advanced models related to large strain thermo-elasto-plastic behavior of aluminum alloy AW5083, which can reproduce the material response at different temperatures from room temperature up to 500 degrees Celsius. Significant focus is placed on the internal sources of cooling and heating resulting from thermo-elastic and thermo-plastic couplings, respectively, and the influence of elevated temperature on couplings. The formulation of the constitutive description is based on the thermodynamic approach. Two models are presented and tested: including temperature-dependent and temperature-independent plastic free energy function. Numerical tests of the developed models are carried out for a uniaxial tension test. For the sake of comparison with experimental results, a dogbone specimen examined in a tensile machine is analyzed.
Copyright (c) 2025 Agnieszka Sobierańska, Balbina Wcisło https://creativecommons.org/licenses/by/4.0
On the out-of-plane deviation of the bending deformation states of moderately thick bars of asymmetric cross-sections
A characteristic feature of the six-parameter theories of bars is a coupled form of the constitutive equations; in particular the equations linking transverse forces with transverse shear deformations cannot be, in general, decoupled, keeping a separated form of the remaining constitutive equations. The mentioned feature of the constitutive equations implies that within the six-parameter theories of straight elastic prismatic bars there do not exist, in general, plane states of bend-ing/shearing deformations. Thus, any vertical load causes lateral deflections, the only exception being the pure bending problem. The present paper delivers analytical solutions: the closed formulae for shape functions, i.e. deformation states associated with kinematic loads at the ends, and solutions to selected static problems corresponding to the transverse span load. Although elementary, the presented solutions seem to be derived for the first time. In particular, the hitherto published shape functions concerned the theories of moderately thick bars in which all the constitutive equations are decoupled.
Copyright (c) 2025 Radosław Czubacki, Zofia Kozyra, Tomasz Lewiński https://creativecommons.org/licenses/by/4.0
Analysis of a Variable Geometry Radial Inflow Turbine Using 1D Mean-line Model
Despite great progress in 3D computational fluid dynamics (CFD), mathematical modeling used for turbomachinery analysis, the prediction of flow parameters in the rotor (impeller) of radial inflow turbines using existing turbulence models often yields unsatisfactory results. This is because real physical processes related to turbulence are very complex. Other limitations of CFD tools include numerical errors due to finite difference approximations. Thus, for the analysis and optimization of radial inflow turbines, empirical loss correlations applied to a mean-line 1D mathematical model can provide faster and more accurate results compared to CFD simulations. In this study, a 1D approach was used for the mathematical modeling of gas flow in a variable geometry radial inflow turbine with a vaneless volute distributor (VVD). The variable geometry turbine (VGT) was part of a turbocharging system. Combustion engine operation mode with high-power and low-crankshaft rotational speed was chosen, as engine performance under this condition is sensitive to turbocharger adjustment in terms of break specific fuel consumption (BSFC) and other critical parameters. An experimentally-based approach was used where gas flow characteristics in the VGT were calculated under real engine-turbocharger operating conditions. Accordingly, exhaust gas parameters were first measured on an experimental setup. Mathematical modeling then allowed to assess how adjustment in VGT influenced turbine indices, including loss distribution across the stage. It was also validated in this study that during high-load and low-crankshaft operating conditions of the compression ignition (CI) engine, it is recommended to minimize the cross-sectional area at the outlet of the volute acceleration section in the VGT. This adjustment results in better fuel efficiency and lower thermal loads on turbine components, despite a slight reduction in the turbine’s overall efficiency.
Copyright (c) 2025 Dmytro SAMOILENKO https://creativecommons.org/licenses/by/4.0
Blade prime-number / uniform angular distribution criterion for vibration reduction
Currently, the vibration noise of casting cleaning equipment exceeds 95 dB, which not only impacts the equipment's service life but also jeopardizes workers' health. The primary cause lies in the resonance tendency resulting from an uneven distribution of blades in the shot blasting device. The prime-number / uniform angular distribution criterion and the dynamic balance elimination relation are established in this paper, aiming to minimize resonance coupling while considering the internal characteristics of the shot blast device and blade assembly. Subsequently, the shot blasting device of seven prime-number angular front-curved blades was designed and established, and the dynamic balance caused by uneven blade distribution was offset by drilling. We employ discrete element method analysis to evaluate projectile velocity and stability. Results indicate that shot velocity reaches a maximum of 75 m/s with fluctuations within 4 m/s. After reaching 0.24 s, particles accelerated by the shot blasting device achieve relative stability. Finally, vibration data acquisition at a sampling frequency of 10 Ksps demonstrates that noise levels are reduced from 97 dB (traditional structure) to 93.3 dB (new model). This new criterion for shot blasting machine models mitigates vibrations during operation while enhancing working conditions and improving overall stability and reliability.
co-prime / uniform vibration reduction selection criteria
shot blasting device of 7 co-prime front curved blades
Copyright (c) 2025 Yong Li, Yaao Di, Wenzheng Dong, Fangxiang Yin, Yihao Yin, Shanling Han https://creativecommons.org/licenses/by/4.0
Graphical Method for Synthesizing a Four-Bar Linkage with Specified Coupler Angular Reversal Positions
Graphical methods remain an important tool in the theory of mechanisms due to their ability to visually convey fundamental kinematic principles. They are particularly useful in early design stages and in educational contexts, where intuitive understanding is essential. Among the applications of graphical synthesis methods, mechanisms that require a link to momentarily stop at specific angular positions—commonly referred to as angular reversal positions—are of particular interest. While various analytical and numerical methods exist for designing such mechanisms, they typically focus on dwell positions of rotational or translational links and rely on optimization techniques, often at the cost of geometric transparency. This paper presents a graphical synthesis method for a four-bar linkage designed to achieve two prescribed positions at which the coupler reverses its direction of rotation. This specific problem has not been previously addressed in the literature. It emerges in mechanisms used for emptying containers, where the coupler carries the container and must instantaneously pause at two distinct angular positions to ensure stable discharge. Unlike many graphical methods that involve ambiguity related to trial-and-error selection of geometric parameters, the proposed technique guarantees solution correctness and uniqueness while also satisfying the Grashof conditions. This contrasts with numerical methods, where constraint checking is often deferred until the final stages. The construction proposed here is both practically relevant and theoretically novel, broadening the scope of synthesis methods to encompass mechanisms exhibiting link dwells in planar motion, and reaffirming the relevance of graphical approaches.
Copyright (c) 2025 Jacek Buśkiewicz https://creativecommons.org/licenses/by/4.0
Performance of a Hybrid Ichthyoid-Waterjet Articulated Propulsor
The concept of a bioinspired ichthyoid-waterjet propulsor for autonomous underwater vehicles (AUVs) is investigated. The propulsor consists of an articulated fluid-conveying pipe with a propulsive fin at the end. Water drawn into the hull is accelerated to a supercritical velocity, which yields flutter vibrations of the propulsor resembling the motion of a swimming fish. The fin acts on the surrounding water and generates thrust. At the same time, the ejected water produces recoil. Using the proposed dynamical model, three types of propulsors for different swimming speeds are investigated. At low swimming speeds, the propulsive force generated by the propulsors can be up to 30% higher than the thrust of a conventional waterjet propulsor with the same physical parameters. However, this advantage in the generated thrust decreases with the swimming speed increase. The results are obtained by analyzing the approximation of the bifurcating solution and numerical simulations of the differential equation governing the dynamics.
Copyright (c) 2025 Tomasz SZMIDT https://creativecommons.org/licenses/by/4.0
Analysis of the Braking Process for Curvilinear Motion of Vehicle
Road incident reconstruction frequently includes the possibility of avoiding a collision. To perform such analysis, it is necessary to compare the available distance with the minimum braking distance. Therefore, to avoid a collision, the braking distance must be shorter than the available distance. The braking distance depends on parameters such as tyre-to-road adhesion coefficient, the initial velocity of a vehicle, the driver’s reaction time and the time needed to reach full braking force. However, the problem is that, in practice, none of these values are known during traffic incident reconstruction. As a result, the estimated vehicle velocity is uncertain. This is due to the method used to reconstruct a road incident (and the errors in the evidence data). The tyre-to-road adhesion coefficient depends on many factors and can be estimated with limited accuracy, usually ±0.1. The uncertainty of the estimate is approximately ±15%. The reaction time of a specific driver under the conditions present during a road incident is not precisely known. Therefore, an average value for most drivers is taken into account. It is assumed that a healthy driver’s reaction time should not exceed this value, and a longer reaction time is associated with incorrect driving behavior. The time taken to reach full braking force in a real situation is also unknown. Usually, average values are taken from the literature, without the analysis of a technical condition of a vehicle. This article considers the mechanics of vehicle braking, taking into account the action of lateral forces on this vehicle while considering a curved track. The maximum deceleration during braking is determined analytically, and a condition is formulated to indicate whether it is justified to use an advanced computational model instead of the basic one described in the literature. The analysis includes some dimensionless parameters describing the position of the center of gravity, tangential forces between the tyre and the road, the intensity of turning and braking, suspension characteristics, and asymmetrical mass distribution. This dimensionless approach may be useful for applying the presented analysis of braking on the road arc in accident reconstruction, especially when comparative analysis is recommended.
Copyright (c) 2025 Piotr FUNDOWICZ, Hubert SAR, Mateusz BRUKALSKI, Michał ABRAMOWSKI https://creativecommons.org/licenses/by/4.0
Energy Efficiency of an LPG-Powered Extended-Range Electric Vehicle
This paper deals with energy efficiency evaluation of an extended range electric vehicle (EREV) equipped with a range extender (REX) powered by liquefied petroleum gas (LPG). The investigation is based on simulation, with key input data derived from empirical studies carried out by the authors. It includes four target driving ranges (200, 300, 400, 500 km), six driving cycles (WLTC 3b, FTP-75, CLTC-P, Artemis 130, NYCC, HWFET) and three battery size variants for the WLTC 3b cycle. The influence of the these factors on the overall efficiency and specific energy consumption of the EREV is assessed. The results are analyzed in terms of the number of REX activations per 100 km and the total REX operating time.
Copyright (c) 2025 Paweł KRAWCZYK, Artur KOPCZYŃSKI, Jakub LASOCKI https://creativecommons.org/licenses/by/4.0
On Frequency Dependence of Stability in Materials with Fractional Viscosity
Material instability refers to the tendency of materials to undergo alterations in their properties in loading. The concept of instability is governed by the constitutive equation of solids. Our analysis uses the entire set of equations describing the motion of solids, including the kinematical equation and Cauchy’s equations of motion. Damping, or rate-dependence, plays a crucial role in stability. A potential generalization involves the utilization of fractional-order derivatives of the strain or stress tensors. The stability analysis primarily focuses on periodic perturbations. The mechanism of loss of stability on various parts of the stability boundary is under consideration.
Copyright (c) 2025 Peter B. Béda https://creativecommons.org/licenses/by/4.0
Determination of Operating Conditions of a Probe Block Designed for Fault Diagnostics in Rail Heads
In this paper, the key parameters influencing the proper operation of ultrasonic probes for railway rails diagnostics are determined. The goal is to test a set of ultrasonic probes under conditions occurring at high diagnostic speeds. Four issues are studied in more detail. The probe block-rail contact force required to obtain maximum echo level is determined. In the authors’ opinion, the key aspect is the design of the water irrigation nozzle shape in order to produce a laminar couplant flow under the probes. The dependence of the amplitude of the recorded echo on the coupling layer thickness is experimentally investigated. The population of registered signal samples is processed to determine the testing speed limit, which resulted from the loss of data validation ability. The speed limit is calculated based on the average value of the amplitude of the measured signal and the standard deviation of the registered population of amplitudes. The conducted research allows the authors to conclude that the instrumentation they developed enables the recording of an ultrasonic signal propagating through the tested rail at scanning speed of up to 100 km/h.
Copyright (c) 2025 Zbigniew RANACHOWSKI, Sławomir MACKIEWICZ, Tomasz KATZ, Tomasz DĘBOWSKI, Grzegorz STARZYŃSKI, Marcin LEWANDOWSKI, Łukasz ANTOLIK https://creativecommons.org/licenses/by/4.0
The Development Features and Design of a Vibratory Gyroscope with a Metallic Cylindrical Resonator
This paper presents the results of developing a vibratory gyroscope with a cylindrical resonator made of Elinvar alloy. The vibratory gyroscope operates in three modes. These modes include rate mode, rate-integrating mode, and a new, third, differential mode. The differential mode can simultaneously measure two opposite angular rates, Ω and −Ω. A block diagram of the standing wave control system for each mode is presented. The advantages and disadvantages of each of the modes are analyzed. A triple-mode gyro is proposed. The results of experimental studies and simulation data are also presented.
Copyright (c) 2025 Valerii CHIKOVANI, Serhii HOLOVACH, Hryhorii STROKACH, Vadym AVRUTOV https://creativecommons.org/licenses/by/4.0
Multi-Objective Optimization of Hobbing Process Parameters Based on Response Surface Method
In hobbing machining, gear geometric accuracy is an important factor affecting gear working performance, which is determined by the interaction of different process parameters. To improve the geometric accuracy of hobbing surface and obtain the minimum geometric error, this paper adopts the response surface method (RSM) to study the effects of various technological parameters on the geometric accuracy, and explores the influence law of various factors on the geometric accuracy through the response surface diagram. The mathematical models of total profile deviation, total helix deviation, cumulative total deviation of tooth spacing and radial runout were established based on response surface method, and the reliability of the models was tested by variance analysis. Non-dominated sorting whale optimization algorithm (NSWOA) was used to solve the mathematical model, and Pareto solution set was obtained. Entropy weight-TOPSIS method was used to determine the optimal scheme after NSWOA algorithm optimization. After optimization, the total deviation of tooth profile is reduced by 8.04 %, the total deviation of helix is reduced by 9.17 %, the cumulative total deviation of tooth spacing is reduced by 3.88 %, and the radial runout is reduced by 7.45 %, which proves that the optimized scheme can improve the gear accuracy after hobbing machining, and provides a reference for the reasonable selection of gear hobbing process parameters.
Copyright (c) 2025 Yazhou Wang, Xiaohui Yin https://creativecommons.org/licenses/by/4.0
Dynamic Eccentricity Modeling of a Switched Reluctance Motor
The switched reluctance motor (SRM), known for its robust and simple construction, is widely utilized in critical applications. This study investigates the impact of rotor dynamic eccentricity on the motor's current signal. Our research introduces a straightforward diagnostic method to detect and quantify dynamic eccentricity by analyzing the current signal spectrum. This approach specifically focuses on identifying amplitude increases in characteristic additional harmonics, leveraging fundamental electromagnetic transformations to eliminate the need for complex algorithms. Through coupled computer simulations, combining a finite element analysis model (FEMM) with dynamic equation solutions in Simulink, this study identifies specific eccentricity ranges and their corresponding characteristic current values, offering a reliable tool for SRM condition monitoring.
Copyright (c) 2025 Jakub LORENCKI, Adrian CHMIELEWSKI https://creativecommons.org/licenses/by/4.0
Simulation of Vibro-Isolation Performance For Sensitive Cargo Transportation on Planforms with Quasi-Zero Stiffness Suspension Under Impact Perturbations
This work deals with the theoretical modeling of the vertical dynamics of a specialized vehicle featuring a dual suspension system. Vehicle ride quality is essential for ensuring the safety and comfort of passengers and the protection of sensitive or hazardous cargo. The study focuses on a two-axle vehicle model with a dual suspension system. The first level comprises a traditional suspension with linear stiffness, while the second level features nonlinear quasi-zero stiffness (QZS) characteristics. The research employs a discrete nonlinear dynamic model considers the vertical displacements and angular rotations of the vehicle’s masses. The nonlinear QZS response is modeled to optimize vibration isolation performance under varying load conditions, while damping effects are included via a Rayleigh dissipation function. The integral characteristics of the QZS element are also studied in detail using finite element (FE) computer simulations in a 3D statement. These simulations provide a comprehensive understanding of the mechanical response and stress-strain distribution within the QZS element, validating its performance under real-world conditions. The results demonstrate the influence of the nonlinear suspension characteristics on the vibration isolation performance and load stability. The QZS-based suspension effectively reduces dynamic stresses, particularly under low-frequency excitations, while maintaining structural integrity and operational efficiency.
Copyright (c) 2025 Oleksiy Larin, Ksenia Potopalska, Galina Timchenko, Nikita Vasylchenko https://creativecommons.org/licenses/by/4.0
Comparison of Gantry Drive and Crankset: A Pilot Study Across a Broad Power Spectrum
The gantry drive was originally invented in 1948 in England and was “rediscovered” in Poland in 2019 while working on lightweight, personal, compact vehicles. In this study, the gantry drive is subjected to dynamic tests against the background of the commonly known crankset. The aim of the dynamic tests is to develop power curves and measure efficiency for various human-mechanism systems, i.e., the hand-driven crankset, the leg-driven crankset, and the gantry drive. Pilot dynamic tests have shown many advantages of the gantry over the crankset; in general, test participants were much less tired when using the gantry drive.
Copyright (c) 2025 Łukasz BEREŚ, Marcin OBSZAŃSKI, Paweł PYRZANOWSKI https://creativecommons.org/licenses/by/4.0
Prediction of Soil Liquefaction Using Machine Learning Approaches
In the geotechnical engineering field, the assessment of liquefaction potential is a critical aspect of site evaluation. This work focuses on the application of support vector machines (SVM) to improve the accuracy of liquefaction potential evaluation. Input data were collected from the authors' previous study and include parameters such as groundwater table (GWT), depth, fineness content, peak ground acceleration (PGA), corrected SPT-N value, total stress, and effective overburden stress. Radial basis function (RBF), linear, polynomial, and sigmoid are the four SVM kernel functions that are examined in this study to model liquefaction-related data using three approaches: grid search cross-validation, k-fold cross-validation, and fuzzy c-clustering means (FCM). Several performance metrics, including accuracy, precision, recall, and the area under the receiver operating characteristics (ROC) curve (AUC), among others, are used to evaluate the developed machine learning (ML) models. The linear and polynomial functions, for the grid search cross-validation approach, show higher performance with an accuracy of 94.64%, recall of 95.55%, F1-score of 96.63, and AUC of 0.99 on the testing data. For the k-fold partitioning approach, the RBF yields higher performance metrics compared to the other three functions, with an accuracy of 92.73%, precision of100%, F1-score of 95.0%, and AUC of 0.98. In the FCM technique, the linear and polynomial kernels again yield greater accuracy, precision, F1-score, and specificity, while, the AUC values of the sigmoid and RBF kernels are higher. The current analysis recommends the RBF over other mathematical functions based on the k-fold partitioning technique after evaluating all performance matrices.
Copyright (c) 2025 Md. Mahabub RAHMAN, Md. Belal HOSSAIN, Abu SAYED https://creativecommons.org/licenses/by/4.0
Effect of Initial Scratch on Ship Bottom Plate Corrosion Rate and Structural Crashworthiness in Grounding Incidents
Hitting an object in the ocean can peel off the coating on a ship's plate. The exposed plate can be vulnerable to corrosion because it is exposed to the environment and seawater, which can degrade its strength. So, the crashworthiness of the bottom plate should be evaluated in the event of a grounding incident. The ratio of the scratch area and the number of stripes are used as experimental variables. Based on seawater corrosion experiments, the plate's corrosion rate increases quadratically with the scratch area, which is then used for grounding simulations. Eighteen grounding scenarios, based on scratch size, dimensions, and corrosion exposure, reveal that only two or three stripes significantly reduce the plate’s strength in simulations. In addition, in the case of two or three stripes of scratches, corrosion further reduces the plate’s strength in the grounding simulations. This plate has limited space in the vertical direction, which influences the horizontal stripe of scratches and affects the plate's strength in grounding simulation, as compared to the vertical stripes. Besides this, the pattern of crack propagation depends on the reaction force.
Copyright (c) 2025 Ocid MURSID, Dean Nadhif ALFARIS, Tuswan TUSWAN, Ahmad Fauzan ZAKKI, Aulia WINDYANDARI, Karno R. MALAU, Haris NUBLI https://creativecommons.org/licenses/by/4.0
Multi-Objective Design of a Pneumatic Adaptive Impact Absorber
This manuscript proposes a multicriteria approach to the design optimization of adaptive pneumatic impact absorbers. The considered absorber consists of two sealed chambers separated by a piston with an internal valve. Proper valve control affects gas flow between the chambers and ensures a flat reaction force profile over a possibly long piston stroke. The design of such an absorber is defined by three parameters: initial gas pressure, diameter, and length. For a given range of impact conditions, the worst-case maximum deceleration and maximum mass flow rate are used as design criteria in a multicriterial minimization problem. Solutions to this problem provide an optimal balance between impact absorption performance and the technical requirements the valve must meet. An example is considered, which illustrates the Pareto-optimal solutions in the design space and the complex interdependency between initial pressure and absorber diameter at each absorber length. The results demonstrate that a proper choice of design parameters can result in significant performance improvements.
Copyright (c) 2025 Rafal WISZOWATY, Cezary GRACZYKOWSKI, Grzegorz MIKUŁOWSKI, Jan HOLNICKI-SZULC, Zbigniew WOŁEJSZA, Anita ORŁOWSKA-GAŁĘZIA, Łukasz JANKOWSKI https://creativecommons.org/licenses/by/4.0
Characteristics Evaluation and Application of SBS Composite Modified bitumen Materials in Low Temperature Environment
To improve the resistance of asphalt pavement to low temperature cracking, the study proposes a composite modified asphalt based on styrene butadiene styrene copolymer and rubber crumb. It is also tested for its performance in low temperature environment. The test results indicated that although after aging and freeze-thaw cycles, the creep rate of both modified asphalt and styrene butadiene styrene copolymer/rubber crumb were reduced. However, the creep rate of styrene butadiene styrene copolymer/rubber crumb composite modified asphalt was always better than that of styrene butadiene styrene copolymer modified asphalt. As an example, the creep rate of aged asphalt was 0.37 and 0.44 at -12°C, respectively. When asphalt mixes underwent freeze-thaw cycles and age, their fracture energy densities all drastically decreased. The fracture energy density of styrene butadiene styrene copolymer/rubber crumb composite modified asphalt mixtures, on the other hand, was larger than that of styrene butadiene styrene copolymer modified asphalt mixtures. The above results indicate that the composite modified asphalt with styrene butadiene styrene copolymer/rubber crumb has good rheological ability and freeze-thaw resistance, which can effectively ensure the low temperature performance of asphalt pavement.
Copyright (c) 2025 Wenxiao Ren, Ping Li https://creativecommons.org/licenses/by/4.0
Assessment of Methods for Determining Vehicle Emission Characteristics
This paper presents an analysis of pollutant emissions (carbon monoxide, hydrocarbons, nitrogen oxides, methane, non-methane volatile organic compounds and carbon dioxide) from a passenger car, particularly under real-world driving conditions, to more accurately model the impact of transport on the environment. These pollutants were selected due to their regulatory relevance and significant environmental and health impacts. A mathematical model developed in this study was used to estimate emissions, with vehicle speed identified as a key parameter influencing emission levels. Various speed ranges and their impact on emission levels were considered during parametric identification. Since the relationship between pollutants and speed is nonlinear, the least squares method was applied to estimate model parameters for the different pollutants. The model developed in the paper allows for precise emission prediction for various vehicle use scenarios. The scenarios analyzed include urban driving conditions with vehicle speeds not exceeding 60 km/h. The selected speed profile was first recorded in real-world traffic using a portable emissions measurement system (PEMS) and subsequently reproduced on a chassis dynamometer to ensure test repeatability under controlled laboratory conditions.
Copyright (c) 2025 Piotr LASKOWSKI, Edward KOZŁOWSKI, Magdalena ZIMAKOWSKA-LASKOWSKA, Piotr WIŚNIOWSKI https://creativecommons.org/licenses/by/4.0