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EN
Spur gear, helical gear, worm gear, and bevel gear are all important components in industrial applications such as vehicles, pushes, conveyors, elevators, bowl mill, rolling mills, ribbon blender, machine tools, aeroplanes, and windmills. When various types of defects, such as wear, tooth breakage, corrosion, and scratches on bearings, appear in gearboxes, normal machine function may be abruptly terminated. As a result, output and dependability suffer. As a result, several quality tracking and evaluation approaches have been adopted by companies. Finite element analysis (FEA) is one of the approaches. This research paper presents the FEA of a ribbon blender worm gear pair by using Ansys 18.0 to identify the weak gear of the worm gear pair, natural frequency, and deformation. Proe-5 utilized for creation of three-dimensional geometry of threaded worm and toothed worm wheels, as well as other related elements such as shafts and bearings. Steel is used for the worm, shaft, and bearing, whereas bronze is used for the worm wheel. Ansys 18.0 is implemented to carry out worm gear pair model analysis. The results demonstrate that the worm wheel had the most deformation when compared to the worm, and that the natural frequency is greater than the operational frequency of the worm gear pair. The findings of the research study, worm wheel deteriorate early than worm, model analysis plays a significant role in vibration monitoring of worm gear pair, and this work is valuable for further fault analysis of ribbon blender worm gearbox utilising vibration response.
EN
Wood is an anisotropic material with a complex structure. It is very difficult to examine the properties of complex structured materials. Finite element analysis is a technique that can be used to analyze the mechanical behavior of wood and wood-based materials. The objective of this study is to determine the mechanical properties of Oriental plane (Platanus orientalis L.) wood both experimentally and using finite element analysis. For tensile strength and compressive strength, with the aim of determining the wood’s behavior depending on its anisotropic axes, samples were prepared in three axial directions: radial, tangential and longitudinal. Under the same conditions and with the same dimensions, longitudinal samples were modeled in a computer environment using finite element analysis. ANSYS Multiphysics/LS-DYNA was used for simulation. It was determined that the laboratory results and the simulation results were in good agreement, with a similarity ratio of over 90%.
EN
Additive manufacturing (AM) technologies have been gaining popularity in recent years due to patent releases – and in effect – better accessibility of the technology. One of the most popular AM technologies is fused deposition modeling (FDM), which is used to manufacture products out of thermoplastic polymers in a layer-by-layer manner. Due to the specificity of the method, parts manufactured in this manner tend to have non-isotropic properties. One of the factors influencing the part’s mechanical behavior and quality is the thermoplastic material’s bonding mechanism correlated with the processing temperature, as well as thermal shrinkage during processing. In this research, the authors verified the suitability of finite element method (FEM) analysis for determining PET-G thermal evolution during the process, by creating a layer transient heat transfer model, and comparing the obtained modelling results with ones registered during a real-time process recorded with a FLIR T1020 thermal imaging camera. Our model is a valuable resource for providing thermal conditions in existing numerical models that connect heat transfer, mesostructure and AM product strength, especially when experimental data is lacking. The FE model presented reached a maximum sample-specific error of 11.3%, while the arithmetic mean percentage error for all samples and layer heights is equal to 4.3%, which the authors consider satisfactory. Model-to-experiment error is partially caused by glass transition of the material, which can be observed on the experimental cooling rate curve after processing the temperature signal.
EN
The mechanical overloading of temporomandibular joint (TMJ) is generally linked to temporomandibular disorders (TMD). However, in patients with a typical combination of maxillofacial morphology and occlusal features, the reduction of joint load and treatment with general occlusal splints are often ineffective. This study investigates the biomechanical behavior of the stomatognathic system in a TMD patient with personalized splints by finite element analysis. The therapeutic position, determined based on the intercuspal position, served as the basis for designing personalized customized splints. The design of occlusal contact and splint structure was evaluated in terms of their impact on the maximum stress level in the TMJ and the biting forces on the dentition. The relationship between joint stress and biting force was further examined during treatment with different customized splints. In preoperative case, there was a significant increase in stress level and stress concentration in the medial to posterior band of the articular disc. However, in all customized splint cases, the highest stress area shifted to the intermediate zone and exhibited a decrease. Notably, the bi-splints demonstrated superior ability in relieving overloading and balancing the occlusal force on both sides of the dentition, as verified by clinical treatment. The predictable simulated results offer valuable interactive information regarding TMJ overload, aiding doctors in making better-informed clinical decisions in future.
EN
This paper reviews studies on the modelling of the Mannesmann effect, which leads to the formation of an axial crack in parts formed by cross and skew rolling. This effect also occurs in the rotational compression (RC) test of a cylindrical specimen, which is used to determine the critical damage value. RC tests were carried out under laboratory conditions at the Lublin University of Technology on C45 steel specimens formed at 950°C. Based on the tests, the crack propagation was presented as a function of the progress of rotational compression, measured by the length of the deformation path. The RC tests were numerically modelled in Forge® using four ductile fracture criteria. The effectiveness of the Mannesmann effect modelling was evaluated by comparing the numerically predicted cracks with the experimentally determined ones. In addition, the influence of an occurring axial crack on the stress state in the forming specimen was analysed.
EN
Based on the experimental test results of the authors, this investigation is concerned with the finite element analysis to examine and compare the load values and failure modes of the authors’ results. This research was conducted using the Abaqus software. The experimental work included the fabrication of twelve plate girders with honeycomb and flat web plate corrugation patterns, which were then tested under a single concentrated load at the midspan. According to the corrugation dimension or outer honeycomb web thickness, the honeycomb steel plate web girder is divided into three groups (60 mm, 80 mm and 100 mm). The specimens also involved plate girders with a flat web. The specimens were created with three lengths (600 mm, 1,200 mm and 1,800 mm). The Abaqus software was used in finite element models to simulate the concentrated load. The numerical results demonstrated that the 60 mm thick honeycomb web provides a greater load-bearing capacity and shear strength than other girders. The 20 mm honeycomb corrugation on the steel plate girder indicates the increased and improved shear resistance. The conclusion was that as the width of the corrugation increased, so did the steel web’s ultimate load and shear strength, resulting in a positive relationship between the critical shear buckling load of the web and the moment of inertia at the strong axis. When the dimension of the corrugation increases, the moment of inertia of the Y axis (Iy) decreases; thus, the plate girder will fail with a less critical buckling load (Pcr). Also, it can be concluded that as the steel plate thickness of the honeycomb web increases, the shear resistance increases as well. However, the spacing between the intermediate stiffener or the horizontal spacing of the web panel can enhance the shear resistance of honeycomb web girder if it was decreased due to increasing the action of tension field force that resists the diagonal tension developed at the web panel by the applied midspan concentrated force.
EN
The effective thermal conductivity and air permeability of a multifilament polyester yarn used in sports T-shirts was investigated by computer modeling using finite element analysis (COMSOL Multiphysics, ABAQUS/CAE). It has been shown that the number of fibers, the porosity of the yarn and the proportion of fibers in the volume fraction of the yarn have a direct effect on the effective thermal conductivity and air permeability of the multifilament yarn. It was found that with the increase in the number of fibers, the porosity of the yarn decreases linearly, while the volume fraction of the fibers increases, and thus the effective thermal conductivity increases. In addition, air permeability decreases exponentially.
PL
Zbadano efektywne przewodzenie ciepła i przepuszczalność powietrza wielowłókienkowej przędzy poliestrowej stosowanej w koszulce sportowej poprzez modelowanie obliczeniowe z użyciem analizy elementów skończonych (COMSOL Multiphysics, ABAQUS/CAE). Wykazano, że liczba włókien, porowatość przędzy oraz udział objętościowy włókien w przędzy mają bezpośredni wpływ na przewodzenie ciepła i przepuszczalność powietrza przędzy wielowłókienkowej. Wraz ze wzrostem liczby włókien porowatość przędzy maleje liniowo, natomiast zwiększa się udział objętościowy włókien, a tym samym efektywne przewodnictwo cieplne. Ponadto przepuszczalność powietrza maleje wykładniczo.
EN
Mechanical vibrations are a common problem encountered in many machines, especially for vertical turbine pumps. These pumps are generally difficult to stiffen or damp, but the effective diagnosis must begin with an understanding of the underlying vibratory sources. In the present work, a deep well vertical turbine pump experienced extremely high vibrations for a long time although it still being new. It hasn't been in operation for over 6 months. The pump system suffers from extremely high vibration levels relative to the rotational speed (1X motor dominant frequency). An efficient strategy was implemented by using well-conceived techniques. The experimental modal analysis confirmed a presence of a natural frequency. Modifications were carried out to overcome resonance. Finite element analysis was done to determine the reed critical frequencies as a powerful tool to identify and mitigate vibration issues. On-site motor balancing was done to remove vibrations due to the residual imbalance. Results revealed decreasing vibration level by about 66% after solving all problems.
EN
In order to study the mechanical behavior of concrete-filled steel tube(CFST) short column with different void ratios under a certain eccentricity. A fiber model of concrete-filled steel tube section with different void heights was established. Compared with existing model test data, the axial force and flexural moment strength models of concrete-filled steel tube columns with different void ratios were established. The results show that, in the case of different void ratios, the cross-section strength envelope shows an overall contraction tendency with the increase of void ratio, and each line is basically parallel. A model for calculating the coefficient of axial load degradation was established. The Han’s flexural moment strength model of the flexural component was revised, and the strength model of concrete-filled steel tube column under eccentric compression considering void ratio was established, which provides a theoretical basis and method for the safety assessment during the operation of concrete-filled steel tube arch bridges.
EN
A quantitative study is performed to determine the performance degradation of Y-shaped reinforced concrete bridge piers owing to long-term freeze-thaw damage. The piers are discretized into spatial solid elements using the ANSYS Workbench finite element analysis software, and a spatial model is established. The analysis addresses the mechanical performance of the piers under monotonic loading, and their seismic performance under low-cycle repeated loading. The influence of the number of freeze-thaw cycles, axial compression ratio, and loading direction on the pier bearing capacity index and seismic performance index is investigated. The results show that freeze-thaw damage has an adverse effect on the ultimate bearing capacity and seismic performance of Y-shaped bridge piers in the transverse and longitudinal directions. The pier peak load and displacement ductility coefficient decrease with increasing number of freeze-thaw cycles. The axial compression ratio is an important factor that affects the pier ultimate bearing capacity and seismic performance. Upon increasing the axial compression ratio, the pier peak load increases and the displacement ductility coefficient decreases, the effects of which are more significant in the longitudinal direction.
EN
The material deformation behaviour during the innovative SPD process called DRECE (Dual Rolls Equal Channel Extrusion) has been analysed by FEM simulations. In the process, a workpiece in the form of a strip is subjected to plastic deformation by passing through the angular channel; however, the workpiece dimensions remain the same after a pass is finished. Performing consecutive passes allow for increasing the effective strain in the material to a required level. In the conducted simulations two various channel angles (108° and 113°) have been taken into consideration, as well as two processing routes, A and C (without and with turning the strip upside-down between consecutive passes, respectively). The analysis of simulation results has revealed that significant strain and stress inhomogeneities across the strip thickness are generated in a single DRECE pass. The die design (the inner and outer corner radius) and friction conditions affect the material flow, reducing significantly the shear strain in the near-surface regions of the strip. The strain inhomogeneity can be effectively reduced by choosing the processing route C. The strain distributions and the corresponding tensile test results have confirmed that the smaller channel die angle allows to generate larger strain and higher strength of the strip but also reduces its ductility more than the die setup with the larger channel die angle.
EN
To improve the punching shear resistance, an enhanced embedded column base for concrete-filled steel tubes has been proposed, where a pair of strengthening beams are installed on the embedded region of the steel tube by the diaphragm plates. Punching tests were first conducted on eight specimens to investigate the working mechanism of this kind of column base. The test parameters included the length and embedded depth of the strengthening beam. The test results indicated that the punching shear section initiated from the diaphragm plate, which enlarged the punching cone and improved the punching shear resistance. The numerical modelling was also performed. First, finite element models were established and validated against the test results. Full-scale models were then developed to conduct the parametric studies and enrich the database. Finally, a calculation method to evaluate the punching shear resistance of the enhanced embedded column base was proposed and validated. This calculation method takes into account the bonding force, the resistance of the concrete and stirrups on the critical section, and the contribution of the diaphragm plates and strengthening beams.
EN
In order to study the influence of load position and chamfer opening on the shear performance of reinforced concrete (RC) beams with double openings, five 1/3 RC beams were subjected to three equal point loading tests and ABAQUS finite element analysis. The study revealed that the position of the opening in the structure has a significant impact. When the opening is located in the bend-shearing section, shear force cannot be transmitted, resulting in brittle shear failure of the top chord. In contrast, if the opening is in the pure bending section, bending failure of the specimen occurs. The top chord's cross section exhibits a neutral axis, resembling a short beam, leading to the redistribution of normal stress at the opening. Shear capacity decreases as the loading point moves inward from the outside of the opening. Rectangular openings demonstrate better mechanical properties compared to chamfered openings. The findings from finite element analysis (FEA) suggest that the shear performance of RC beams with double openings is mainly influenced by the length of the opening in the bend-shearing section. The shear capacity relies on the presence of shear stirrups with the same length of the opening in the bend-shearing section. As a result, a revised calculation method for the shear bearing capacity of RC beams with double openings, based on different countries' standards, has been proposed. The revised approach was validated using experimental and FE specimens from this study, along with 32 RC beams with double openings from the previous literature. The calculated results demonstrate a satisfactory level of safety, with the revised Chinese standard deviation within 10%.
EN
This paper presents an experimental and numerical investigation on the buckling behaviour of corroded cold-formed steel (CFS) channel section columns under axial compression. 7 stub columns and 7 medium long columns were accelerated corrosion by the outdoor periodic spray test. Prior to compression tests, the mass, residual thickness, surface morphology and initial geometric imperfection of the corroded CFS columns were measured. The failure modes, load-strain curves and load-axial displacement curves obtained from axial compression tests were discussed. Based on the corrosion morphology, the non-linear finite element (FE) model for the corroded CFS columns was then developed. Finally, the calculation method for corroded CFS channel section columns was proposed. The results indicated that with the increasing mass loss rate, the irregularity of residual thickness increased rapidly at first, and then increased slowly due to uniform corrosion. The failure mode of the corroded specimens may change from distortional buckling to local buckling as the mass loss rate increased. With the increase in mass loss rate, the buckling critical load, ultimate load, post-buckling strength and axial displacement corresponding to ultimate load decreased. The failure positions of distortional buckling and local buckling were mainly related to the corrosion degree of the flange and web, respectively. The FE results were compared against the experiment results showing a good match in terms of both the ultimate strength and failure modes.
EN
Featured with a higher velocity, increased power handling capability, and better aging behavior, surface transverse wave (STW) shows more promising prospects than Rayleigh wave nowadays in various sensing applications. The need to design, optimize, and fabricate the related devices motivates the development of modeling and simulation. For this reason, a three-dimensional (3D) finite element (FE) simulation of STW on quartz, considering the crystal cut angle and the electrode effects, is presented in this study. Firstly, we investigated the effects of quartz’s cut angle on the generated waves. Here, the polarized displacements were analyzed to distinguish the wave modes. Secondly, the investigations of the electrode effects on the polarized displacement, phase velocity, and electromechanical coupling factor (K2) were carried out, for which different material and thickness configurations for the electrodes were considered. Thirdly, to examine the excitation conditions of the generated waves, the admittance responses were inspected. The results showed that not only the crystal cut angle but also the density and the acoustic impedance of the interdigital transducer (IDT) material have a strong influence on the excited waves. This article is the first to analyze STWs considering quartz’s cut angle and electrode effect through a 3D FE model. It could provide a helpful and easy way to design, optimize, and fabricate the related surface acoustic wave devices.
EN
Titanium alloys are difficult-to-machine materials due to their complex mechanical and thermophysical properties. An essential factor in ensuring the quality of the machined surface is the analysis and recommendation of vibration processes accompanying cutting. The analytical description of these processes for machining titanium alloys is very complicated due to the complex adiabatic shear phenomena and the specific thermodynamic state of the chip-forming zone. Simulation modeling chip formation rheology in Computer-Aided Forming systems is a practical method for studying these phenomena. However, dynamic research of the cutting process using such techniques is limited because the initial state of the workpiece and tool is a priori assumed to be "rigid", and the damping properties of the fixture and machine elements are not taken into account at all. Therefore, combining the results of analytical modeling of the cutting process dynamics with the results of simulation modeling was the basis for the proposed research methodology. Such symbiosis of different techniques will consider both mechanical and thermodynamic aspects of machining (specific dynamics of cutting forces) and actual conditions of stiffness and damping properties of the “Machine-Fixture-Tool-Workpiece” system.
EN
The article is dedicated to the problem of design of shell structures in terms of architectural form-finding methods from a historical and contemporary perspective. The form-finding theory and techniques formulated by Robert Hooke were put into practice by Antonio Gaudi with his designs of the churches of Colňnia Güelland and Sagrada Familia. Moreover thin concrete shell structures were used in the middle of XX century and their structural forms were derived from experiments with physical models. Innovative form-finding techniques were developed by Frei Otto for the design of membrane structures. The article presents some historic, physical models based methods used for experimental determination of form and verification of the structural systems. Nowadays, computational methods are used in static analysis with dynamic environmental load simulation, which allow predicting the behavior of designed forms and structural systems. Architects can use 3D modelling twinned with visual programming to perform conceptual analyses enabling structural optimization of the architectural form. The Exhibition Pavilion of the University of Zielona Góra concept project was presented as an example of the use of computer numerical form-finding tools in supporting architectural design in the analysis of the effectiveness of structural solutions.
EN
The current collapsible pot hauler uses a wooden frame, thus making much space in the working area of the fishing boat and also at this time challenging to find the best quality wood at this time. In this study, the wood material would replace by metal; the selection of the proper material is critically needed. A suitable material means the applied material has to deal with environmental conditions. Finding the appropriate material applied to the collapsible pot hauler; can be determined using a Multi-Criteria Decision Making (MCDM) approach. After selecting the proper material, the collapsible pot hauler simulates the material stress using the Finite Element Analysis (FEA) simulation. The material for the new model of collapsible pot hauler was selected using the WSM method. The material with the highest rank (selected) is AISI 304, with a preference value of 3.58. The static strength simulation using the FEA method utilizing Solidworks Software shows that the yield strength value is still below the material properties, which a maximum value is 200. MPa, the material safety factor is the minimum value above one, which is 1.24 on the line spool plate shafts. It means that the material AISI 304 is safe to be applied to the collapsible pot hauler.
20
Content available remote Numerical and experimental analysis of the forging of a bimetallic crosshead
EN
The automobile sector has been making increasing efforts to reduce the weight of automobiles, aiming at mitigating pollutant gas emissions. The use of innovative concepts, such as bimetallic components, has become attractive because it makes it possible to increase the strength-to-weight ratio of the components. In this study, the hot forging of a bimetallic crosshead is investigated. In the process, a billet with a cylindrical core of the magnesium alloy AZ61 is enclosed with a hollow cylinder of the aluminum alloy AA 6351 and forged at 400°C. The objective is to reconcile the low density of Mg alloys with the high corrosion resistance of Al alloys. In parallel, a finite element analysis of the process was carried out.
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