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This paper aims to study the efficiency of using prefabricated layers made from plain cementitious composite materials for enhancing the flexural behavior of reinforced concrete (RC) continuous beams. The strengthening system was applied at 20 mm thickness, 150 mm width, and adequate development length. The prefabricated layers were placed in the tension cover in the positive and negative zones. All beams have the same geometric dimensions and positive and negative steel reinforcement ratios. The results showed that the prefabricated layer was deformed with the RC specimen without debonding, which enhanced the cracking patterns and distributed the crack width. A slight improvement in the strengthened beam capacity was 7% for the yielding load and 6% for the ultimate load. The energy absorption capacity of the strengthened beam decreased by 30.67%, whereas both beams achieved the same ductility index.

When diamond scribing knives are used to grind silicon wafers at ultra-high speeds, slight changes in the structure of the diamond scribing knives and changes in the grinding parameters will have a large impact on the processing accuracy and appearance of the silicon wafers. In order to reduce the defective rate of silicon wafers, improve the service life of diamond scribing knives and grinding efficiency. To address this issue, the working mechanism of the scribing knife grinding is analysed in the paper, the influence of spindle speed and feed rate on the quality of the silicon wafer slit when the scribing knife is grinding is studied, and the chipping of silicon wafers is observed through the scanning electron microscope and optical microscope, so as to analyse the shape of the cross-section, length of the cutting edge, concentration of diamond particles in the cutting edge, thickness of the cutting edge and determine the structure of the scribing knife, and to test its influence on the silicon wafer slit by means of the grinding experiments. The structure of the scribing knife was determined, and its influence on the quality of silicon wafer slit was tested by grinding experiment. The results show that the wear rate of diamond particles, slit quality and processing efficiency of the scribing knife are optimal when grinding silicon wafers at 50,000 r/min and 60-80 mm.sec^-1. The above study can help to further understand the wear mechanism of the scribing knife in the process of ultra-high-speed grinding of silicon wafers, improve the machining efficiency, and prolong the service life of the tool.

In order to solve the problem of heterogeneous deformation in the rolling process of 10Ni5CrMoV heavy plate, the effects of uniform temperature rolling (UTR) and graded temperature rolling (GTR) on the microstructure and deformation uniformity of 10Ni5CrMoV steel were studied by means of numerical simulation and verification experiment, and the strengthening mechanism of high permeability rolling process on the rolling deformation of 10Ni5CrMoV heavy steel was clarified. The results show that compared with the uniform temperature rolling process(UTR), different gradient temperature rolling processes (GTR) make the deformation area gradually expand to the core, and the deformation of the core increases significantly. The reduction rate of the first pass gradient temperature rolling processes (FGTR) is about 2.3% higher than that of uniform temperature rolling, and that of continuous gradient temperature rolling (CGTR) is about 5.3% higher than that of uniform temperature rolling. At the same time, the microstructure difference of the core surface is reduced, which is conducive to improving the uniformity of microstructure and properties. At the same time, the microstructure of the core in the rolled is uniformly refined, and the effect is significant.

The fuel content of engine oil is a significant factor affecting its degradation processes, lubricating properties and overall service life, especially in the case of modern internal combustion engines equipped with turbocharging, direct injection and exhaust gas recuperation systems. This study analyzes the dilution of engine oil with fuel in diesel and gasoline engines of vehicles with different degrees of wear, represented by the number of kilometers driven. The main objective of the research is to identify the relationship between the fuel concentration in the oil and changes in its physicochemical properties, as well as the potential impact of this phenomenon on the service life of the lubricant and the suitability of the set replacement intervals. The fuel content was quantified using precise quantitative spectrometric analysis, which allowed comparing engine oil samples taken under different operating conditions, including hot and cold starts, urban and highway operation. The results obtained show that vehicles with higher mileage and higher frequency of cold starts exhibit significantly higher rates of oil dilution by fuel, which directly affects the reduction of its viscosity and lubricating ability. The findings of this study provide important insights for the development of recommendations in the field of engine maintenance, especially with regard to optimizing engine oil change intervals, in order to prevent excessive wear and damage to engine components due to lubricant degradation.

Benzoylation treatment represents a promising strategy to enhance adhesion between plant fibres and polymer matrices. This study aims to improve the properties of epoxy composites using benzoylated fibres of Demostachya bipinnata (Darbha). The analysis focuses on the impact of chemical treatment on the physicochemical and mechanical characteristics of the fibres and resulting composites. After retting and alkaline pre-treatment of the fibres, benzoylation using 10 wt% concentrated benzyl chloride is applied to introduce benzene groups, thereby enhancing the density and chemical stability of the fibres. Results highlight increased density (1869 kg.m-3) and enriched crystalline cellulose composition in benzoylated fibres (BDE) compared to untreated fibres (UDE). FTIR analysis confirms significant structural modifications with the introduction of additional carbonyl and carboxyl groups, reinforcing essential interfacial bonds. Mechanical tests reveal 30% higher tensile and flexural strength for epoxy/BDE composites compared to epoxy/UDE composites, demonstrating the effec-tiveness of benzoylation in improving mechanical properties. Thermal analysis also shows improved thermal stability of BDE fibres, crucial for demanding industrial applications. In summary, this study demonstrates significant enhancement in performance of benzoylated Darbha fibres as composite reinforcements, opening new avenues for their use in sectors such as automotive and construction, where high mechanical strength is crucial.

In order to reveal the action mechanism of different brass solder compositions on the microstructure of weld joints in unleaded-tin-coated coppers brazing-stitch welding, the laser welding process of solar panel busbar was studied by using three different coated brass solders: Sn-37Bi-3Ag, Sn-42Bi-3Ag and Sn-47Bi-3Ag. Scanning electron microscope, energy spectrometer, X-ray diffractometer, tensile testing machine and Vickers microhardness tester were used to test and analyze the influence of Bi element content on the microstructure and mechanical properties of weld joints in solar panel busbar brazing-stitch welding. The results show that: (1) With the increase of Bi element content, the wettability of soldering ceam is gradually improved, and the weld joints eutectic mainly consists of SnAg phase, Ag3Sn phase, Cu6Sn5 phase, Cu3Sn phase, SnAgCu phase, β-Sn sosoloid and Bi with rhombic layered structure. (2) The fracture of weld joints occurred at the interconnection belt side, it presents brittle and ductile mixed fracture. With the decrease of Bi element content, the tensile strength of weld joints gradually increased, and the maximum tensile strength of weld joints was 212 MPa. (3) The of weld joints decreases gradually from the busbar side to the interconnection belt side, and the highest microhardness of weld joints appears at the interface layer, it can reach 330.1 HV. With the decrease of Bi element content, the microhardness of weld joints gradually increased. This paper provides a scientific basis for the optimal selection and use of busbars in solar panels high-quality laser welding.

Core-shell powders have been extensively studied due to their complex structure and wide range of applications. W@Ag core-shell powders are particularly interesting due to the synergy between the tungsten and silver, which can be beneficial in the electronics industry. However, knowledge of their thermal stability is limited, particularly concerning the impact of annealing temperatures on structural integrity and oxidation resistance. In this work, W@Ag core-shell powder was heat-treated in the temperature range 100–700 °C for 1 h in air. Investigation of the microstructural changes using scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy showed that the limiting temperature is 500 °C, when the shell began to decompose and the core began to oxidize. Moreover, X-ray diffraction analysis determined that the phase composition of the thus heat-treated material consisted of approxi-mately 50 % Ag and 50 % Ag2WO4.

Lighter and lighter products are required by aerospace and automotive sectors in order to reduce fuel cost and carbon dioxide emissions and, to allow using green energy propulsion, such as the electric one. In order to lighten parts aluminium alloys, which have a high strength to weight ratio, are the most commonly used metal materials. They are manufactured through plastic deformation processes often by using tailored blanks. This work focuses the attention on semi-finished products obtained by subtract-ing material through machining; they are a further class of tailored blanks. In this work, the design of a simple (almost hemispherical) aluminium alloy sheet component in AA2017 aluminium alloy is analysed, with the help of finite element analysis. In order to reduce the component weight; a circular blank was used, characterised by a variable initial profile of the thickness instead of the conventional disc with a constant initial thickness. Given that a more uniform final thickness profile is determined, enhanced resistance characteristics of the product component are achieved. Therefore, the workpiece will be characterized by a weight reduction of about 8% compared to the analogous ob-tained from a blank with a constant initial thickness.

This essay aims to describe technology and mold design for production of hollow composite parts like carbon rims or sport rackets. Tested materials correspond to those used for composites in sport applications. Production technology called inflatable bladder molding (IBM) is describe with respect to used material, molds and process parameters. Furthermore, prototype mold for verification of flexible bladder, inner pressure and curing conditions is constructed and tested. Construction design of manufacturing mold together with description of technological steps is proposed.

The contribution deals with the study of magnetic structures, computational methods used in analyzing the interaction of magnetic fields with application this knowledge in practice.
The main object of study is design of blocking element of magnetic cycloid gearbox. This paper describes the design methodology of magnetic blocking element, calculation of the braking system, the maximum breakaway torque at slipping in magnetic coupling and power ratios during this action.

The article deals with the design of a robotic workplace for laser engraving. The first part of the article describes the importance of introducing robotics to industry 4.0. Custom solutions work is devoted to the implementation of the six-axis robotic arm UR10. This six-axis robotic arm inserts the designed jig with the semi-finished product into the engraving machine. In the engraving machine, the semi-finished product is engraved on the final product. This saves the operator time to pinpoint the position of the semi-finished product inside the engraving machine. The proposed jig is designed to be universal so that the position in the x-axis and in the y-axis can be precisely defined. At the end of the jig there is a bed for placing the semi-finished product, which can be replaced by another in the case of other dimen-sions of the semi-finished product. The conclusion is a comparison of time savings in individual steps and overall engraving time savings for one engraved part.

Prototype production is a key element in the process of developing a new product. The prototype is important both for the initial materialization of ideas and intentions for product design, as well as for subsequent assessment of the technological design of this design. 3D printing technology is also used today as a suitable technology for prototype production, especially for the possibility of relatively rapid adaptation to complex shape geometries, the ability to produce what would be difficult or impossible to produce with conventional technologies, and last but not least, the increasing availability of 3D printing equipment.This paper demonstrates the principle of production of auxiliary gauges, for checking the dimensions of a prototype product with complex shape, 3D printing and its further possible use in the conditions of an engineering company. The conclusions of the paper should show the possibility and suitability of integration of modern and classical production technologies in the conditions of piece or custom production.

This paper mainly studies the hydrostatic turntable of precision milling and grinding compound machining center in aerospace processing equipment, and innovatively designs and analyzes the mesa. It is proposed to replace the traditional 40Cr with imported marble for the mesa. Firstly, the vibration model of the hydrostatic turntable is carried out. ANSYS Workbench software is used to compare and analyze the original and marble materials. In the process, the static characteristics and the difference of first-order modes of the two materials are compared. In addition, the analytical results are used for manufacturing. The results show when the applied force reaches the limitation 29400N, the maximum displacement of 40Cr increases sharply to 8.9406μm; while the marble material reaches 2.6μm. Meanwhile, it is obtained that the power consumed by marble is reduced by 39.12% compared with 40Cr. The weight of marble is reduced by 39.36% compared with 40Cr. Marble is about 21.59% higher than 40Cr in the comparison of vibration mode results

The vertical stability coil is a set of active feedback control coil that is used to deal with the vertical instability of plasma. To improve the response performance, the coil is mounted in the vacuum vessel, which denotes the coil-body will suffer from large electromagnetic force from the plasma current and poloidal field coils. Besides the current flowing in the feeder is nearly perpendicular with magnetic field originated from toroidal coil. It implies large electromagnetic force will be generated on the feeder. In order to withstand the impact from the electromagnetic force, a series of reinforce compo-nents are designed and installed on the coil. It is necessary to verify whether or not the coil conductor and auxiliary components could successfully bear the shock of large electromagnetic force. A three-dimensional magnetic field model is built to accurately calculate the magnetic field and electromag-netic force. Corresponding to the magnetic field calculation model, a more detailed me-chanical anal-ysis model is created to launch the electromagnetic-structural coupling analysis. Based on the stress analysis results, the local structure of the coil is optimized to decrease the peak stress. The updated model is reanalyzed and stress linearization is exerted to extract the different kinds of stress on the coil components. Finally, the stress is evaluated based on ASME analytical design. The evaluation result is helpful to guide the further design optimization.

Two extendable firefighter ladders, both made of AA 6063 alloy, has been destructively tested accord-ingly to the ČSN EN ISO 1147 to determine the maximal load before their failure. For this purpose, two brand new ladders with a complex profile were compared to the 5-year old one with a far simpler profile. It was found, that the new ladder broke already at a load of 366 (365 kg) while the 5-year old ladder could withstand a much higher load of 426 kg. Since both the ladders broke nearby the guides acting as a mechanical support for their extension, it was of high interest to investigate the cause of different behaviour. Considering the fact, that the brand new ladder had a much more complex pro-file of the beam and the fact, that the guides were welded to the beams, it was of high importance to investigate the influence of the weld on the overall integrity of the ladder. It was found, that the weld itself deteriorated the mechanical properties of the beam reaching the minimal hardness in the dis-tance of 10 mm, which also corresponded with the crack initiation site. This place also showed the lowest hardness reaching only 52 HV 1.

The design features of diaphragm compressors are discussed in this article. The influence of operat-ing factors on the durability and reliability of a diaphragm made of corrosion-resistant maraging steel is investigated. It is shown that to increase the operational reliability of the compressor's diaphragm elements; it is recommended to use a material, the structure of which contains a certain amount of work-hardened retained austenite. This makes it possible to undergo additional martensitic transfor-mation under the action of peak loads in local areas and increases the structural strength of corrosion-resistant steel for the manufacture of a compressor diaphragm.

The article presents problems with commercial inverter source Rapid Arc application on fillet and V-grooved welds. Principal and conditions of the process are explained and especially restriction due to source and feeder upper power limit is described. Case study of "weld design for fabrication" method was demonstrated, where type of weld and shape of groove is designed on the base of experimental results of process penetration behavior at 1/2 V-groove joint. Results are described and discussed, using special welding parameters monitoring equipment and software. A change of metal transfer behavior was recorded in accordance with torch angle setting and originally explained.

The paper deals with the determination of cohesive parameters of adhesive Scotch-Weld DP490 3M. Mode II of cohesive damage were examined. Experimental testing was performed on the test specimens to determine the me-chanical properties of the adhesive according to ASTM D7905. The results of the experimental testing were com-pared with the numerical simulation of the same test. The cohesive parameters of the adhesive were obtained from the numerical simulation. Cohesive parameters of adhesive can be used to design real complex adhesive bonded joints. Cohesive models (specifically cohesive contacts or cohesive elements) are one of the most accurate methods of modeling adhesive bonded joints, so this method is mainly used for parts where it is necessary to ensure suffi-cient strength, such as in automotive, aviation, etc.

The topic of the article is the increase of cutting conditions in the machining of heat-resistant steel using exchangeable inserts. The main part is the design of a new technology for machining one of the heat-resistant materials using replaceable inserts, including a discussion of any defects and economic evaluation. The aim is to reduce production costs and contribute to the elimination of production times. These modifications of technologies have a positive effect on the overall economy of produc-tion and the use of new methods in practice. Heat-resistant steels have found application in many branches of production, especially in the aerospace industry for jet engine components. Their specific properties need a more detailed examination of the optimal conditions for their processing.

This paper aims to design a control jig for cutting inserts measurement. These inserts are made from standardized inserts by grinding. The control jig is intended to be used on two different types of measuring devices and it has to meet the functional requirements of these devices.The intoduction describes specific functional requirements on the jig, provides information about measuring devices and examples of cutting edges grinded on inserts. Next part describes the design of several variants of jig parts and reasons for their application. Paper is focused specifically on design of jig body variants, description of measuring arm and the way of clamping of inserts in the control jig. The measuring range is described for each of proposed variant. In the closing part of the article particular variants are compared according to their suitability, stability during measuring and range of serviceability for measuring of the inserts.

In order to have a good performance of gas exchange in working process, a function of six order polynomial dynamic cam was established in this paper. The influence of the maximum ample factor to valve including the maximum positive and negative accelerations and the minimum curvature radius was analyzed by NLPQL. On this basis, multi-body dynamic analysis for diesel engine valve train was done, valve train dynamic model was established by ADAMS, multidisciplinary optimization process of cam profile and its model was put forward, and ISIGHT software was used to optimization and calculation. Finally, a set of different cam parameters and corresponding valve performance parameters was established, multipart integrated design and multidisciplinary optimization for diesel engine valve cam was realized. This paper provides a new method for the multicomponent integration design and multidisciplinary integration optimization for diesel engine valve train.

The paper deals with a construction design of a versatile adaptive gripper for a robot manipulator. More specifically, it presents construction design of motional kinematics of fingers, which are controlled by a working screw, and also computation of forces and a selection of drive actuating units. Calculation of forces is needed for further correct selection of an engine transmission, considered gearing, belt gear and transmission.
Automation is a process of replacing man's control function by operation of various machines and devices. Automation is a highly complex process including very simple control operations, which are performed automatically by relatively simple devices, as well as very complex control of large production units. Control is a purposeful action of evaluation and processing of information about the controlled object or process, actions in the process (these may include measurement device data, signalling equipment states), and according to them, related machines are controlled so that the prescribed objective can be met - handling piece loads of maximal weight m = 25 kg in this instance.

The paper describes the course, conditions and results of the impact test of the supporting frame of the test station for dynamic tests of gears. The test station makes it possible to simulate different gears operating conditions. The basic support frame structure of the test station was evalu-ated as unsufficient based on the results of measurement and processing of the measured low and high fre-quency vibration values in the verification series of experimental tests. The basic failure of the origi-nal design were the significant resonance actions that were the results of the dominant sources of vibration being near the natural frequencies of the vertical and horizontal beams of the test station base. A structural design of the test station supporting frame was designed and implemented. The goal was to increase the rigidity of the frame and eliminate unwanted resonance phenomena. The impact tests were used to determine the values of the natural frequencies of the most stressed parts of the supporting structure - vertical and horizontal beams, before and after implementation of struc-tural modifications. The comparability of the impact test results was determined by adherence to identical measurement conditions.

The paper deals with the issue of magnetism and its use in mechanical engineering as well as in other industries. Transmission systems are rather frequently present in almost every technical system. The purpose of each transmission system is to transform energy, based on which its quality can be assessed.
The main objective of this paper is the structural design of a magnetic cycloid gearbox, a detailed description of transmission kinematic analysis, elaboration of calculation models for FEM analyses consisting of the analysis of gearing power relations and calculation of maximum torque the gearing is able to transform.

Nitriding is a technology that leads to an increase in the utility value of the product. It’s most im-portant benefits include increased corrosion resistance, abrasion resistance, wear resistance, increased resistance to fatigue failure under cyclic loading, and many others. The design of a suitable nitriding technology not only on the basis of empirics requires a closer study of the relationship between the structure of the nitriding layer, its properties and the course of a particular degradation process. Be-cause the life of most components is related to abrasion on the surface, the occurrence of fatigue cracks and corrosion effects, it is crucial to influence the mechanical and other properties in this sur-face area. High functional requirements are placed on the functional surfaces of steels for weapons production, which lead to a long service life, reliability and dependability of the components of the weapon system and its safe use. The paper discuss the influence of selected nitriding technologies on the mechanical properties of steel 42CrMo4 and 34CrNiMo6, especially on the hard and microhard-ness of surface layers, change of its structure and next to change the surface texture and dimension of component. The steels were nitrided in plasma and gas. Nitriding in gas led to more significant struc-tural changes in the surface layer of both steels compared to plasma nitriding.

One of the key components in making Industry 4.0 a reality includes machines that are able to produce required products and components faster, more precisely and more flexibly than ever before based on so-called reverse engineering technology. Reverse engineering is a technology that enables rapid acquisition of data for CAD, CAM, CAE, thereby greatly shortening the development, design and fabrication of parts. In general, analogue data is converted to digital data, which is further processed. The paper deals with the analysis of prototype models of disc milling cutters with different blade profiles. The inspection of the shape of the disc-type prototypes is based on the reading of the digitized reference CAD model (workpiece with machined grooves), the subsequent positioning of the digitized protrusions of the disc mill cutters (milling cutter with edge profile 1, a milling cutter with edge profile 8) with respect to this reference CAD model, creating a colour map of the deviations at the selected points. The aim of the paper was to analyse the resulting wear (deviation of the dimensions at selected points) on the prototype of the disc milling cutters with the profiles of blades 1 and 8, which was simplified on the workpiece with the machined profiles of the grooves 1 to 4.

The paper presents a concept of the design of gear shaper cutters with curvilinear side flank faces. The problem of forming the outline of the cutting edge of the gear shaper wedge has been discussed and the possibilities of execution of this type of knives have been indicated. The method of forming the rake face of curvilinear side flank face has been presented.

The turning process is one of the most common machining operations in various manufacturing industries. It is conducted by eroding the rotating workpiece using a tool that moves in a linear motion. This study examined the genetic algorithm (GA) as the optimization method for the dry turning process of AISI 316L. GA is a meta-heuristic method that imitates the principle of natural selection, in which the most suitable individuals are selected for reproduction to produce the next generation of offspring. The optimization process was started by executing the selected experimental design based on the process parameters and their levels. The tool nose radius, cutting speed, feed rate, and depth of cut were selected as the process parameters in this study. The outcome of this step was a fitness function that explained the relationship between the process parameters and the material removal rate (MRR) or the surface roughness (SR). GA used the fitness function to produce the optimal process parameters with the highest MRR and the lowest SR in a separate optimization process. The optimization methodology developed in this study can be utilized to predict the optimum value of the MRR and SR for the dry turning process and with less than a 7% deviation from the actual value.

Hydrogen embrittlement involves the interaction between hydrogen and the microstructure of metals, which can lead to an alarming loss of mechanical properties. For advanced high-strength (AHS) steel S960MC grade, which finds application in fields ranging from heavy machinery to construction, understanding this phenomenon is important. The material's complex crystalline lattice, carefully engineered to maximize strength, becomes vulnerable in the presence of hydrogen. The sources of hydrogen that can lead to embrittlement of steel are various. From the exposure of steel to hydrogen during production processes to the absorption of hydrogen from the environment. After the absorption of hydrogen into the material, hydrogen atoms diffuse in the microstructure and look for places with high stress concentration (cracks, inclusions, grain boundaries, etc.). In these regions, atomic hydrogen disrupts interatomic bonds, weakening the material and making it susceptible to embrittlement and subsequent complete failure of the component. This research is focused on how the change in current density affects the hydrogen embrittlement of AHS steel S960MC during hydrogenation. It was found that the mechanical properties of steel decrease at a lower current density, but not to the same extent as at a higher current density. Thus, it can be said that the change in current density influences the hydrogen embrittlement of S960MC steel.

The propagation and velocity of the deformation wave in the thin isotropic plate is investigated. The deformation is induced by the stroke of impact body onto the facial surface of the plate. The plate is supported perpendicularly. The excitation of the plate oscillation is initialized by a unit force (Heavi-side’s jump). The impact body has a rounded facet by radius c = 2.5 mm. Hook's material model and Kirchhoff’s and Flüegge’s geometric model have been investigated. The analytical solutions for both models are presented. The MATLAB script has been assembled to solve material and geometrical mod-els. The results were compared for two selected points on the surface of the plate. Plate deformation was recorded at two points T1 (at a distance of 20 mm from the impact location on the x axis) and T2 (at a distance of 20 mm from the impact location on the y axis).