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International audience; Aeroelastic scaling theory shows that the design problem of aeroelastically equivalent scaled aircraft can be treated as a structural-only design problem if the aerodynamic shape and airflow properties of the full scale aircraft are preserved. In that case, the theory shows that it is sufficient to match the scaled natural mode shapes, frequencies and mass of the reference aircraft. In this paper, we present a new method for the dynamic scaling of flexible structures where the objective function is based on the modal assurance criterion (MAC). This criterion is used for a mode tracking strategy during the optimization process. Finally, we apply this method to a scaled version (1:5) of the uCRM wing, achieving an agreement greater than 99% on the average MAC value of the first 5 modes.

To choose the most suitable method to solve the process parameter optimization of ultrasonic rolling extrusion, the 42CrMo material was taken as the research object. Based on a four-factor five-level orthogonal experiment, the response surface method was used to establish prediction models of the surface roughness, surface residual stress, and work hardening degree. To obtain better Pareto front, resulting in better distribution and convergence of the solution set, the simulated annealing algorithm, particle swarm optimization, second-generation non-dominated sorting genetic algorithm and multi-island genetic algorithm were used to optimize the parameters of ultrasonic rolling extrusion. Comparing the optimization effect with the calculation efficiency, the simulated annealing algorithm is finally selected as the optimization method of the ultrasonic rolling extrusion process parameters, and the optimization parameter domain of the ultrasonic rolling extrusion process is obtained. The optimization model was tested and verified. The results showed that the best optimization effect was achieved after 3000 iterations, and the maximum relative error of the experimental and calculated values for the surface roughness, work hardening degree and residual stress of the optimized 42CrMo material after ultrasonic rolling was controlled within 5%. The established multi-objective optimization model has high accuracy and application value, can realize the optimization of ultrasonic rolling extrusion process parameters.

This work is subjected to the development of a method to identify the elasticity tensor of homogeneous and heterogeneous materials. The materials are created in the form of checkerboards. We solved the direct problem to obtain the strain field using the finite element method, after obtaining this strain field, we created synthetic experimental displacement data by simulation. A re-calibration of the created experimental and simulated data is done based on the principle of the finite element model updating (FEMU), used in almost all domains, in the inverse problem. The minimization of the cost function obtained by FEMU is done by Levenberg-Marquardt algorithm which is very fast and elegant algorithm. A complete study has been done by studying the sensitivity of the identified values with respect to the refinement of the mesh and with respect to the level of disturbance.

Adsorption desulfurization of catalytic gasoline (S Zorb) is an important desulfurization measure that is performed to meet the environmental protection requirements before the final product oil is sold in the market. The desulfurization reactor is a gas–solid two-phase flow environment composed of high-temperature and high-pressure hydrogen-oil mixed gas and sorbent particles; erosion prominently occurs on the reactor distribution plate. This study selects the typical gas–solid two-phase flow conditions and defines the erosion mechanism of the gas–solid two-phase flow environment for the plastic material of E347. Moreover, an S Zorb desulfurization reactor model is constructed, the CFD-DEM model is adopted to predict the wall erosion characteristics in a gas–solid two-phase flow environment, typical erosion laws are obtained via calculations. The erosion laws under the influence of variable parameters are studied based on the orthogonal test, the orthogonal test results show the best parameter combination, the parameter combination yields the maximum erosion rate and high erosion area that are 29.9% and 17.3%, respectively, lower than the existing values. Moreover, an optimum scheme of the inner structure parameters of the reactor is determined for reducing erosion rate and area.

This paper presents a topology optimization formulation based on the Solid Isotropic Material with Penalization (SIMP) method and solved by the Modified Optimality Criteria (MOC) algorithm. It addresses mechanical design problems such as structural reinforcement adding elastic material or vibration reduction using viscoelastic layers. The aim is thus to attach on a pre-existing given structure a design domain in order to improve the behavior of this elastic structure, according to an objective function. This can be useful when one wants to use, for example, additive manufacturing to reinforce a pre-existing structure or to maximize structural damping. Two objective functions are tested in both linear statics and dynamics: a compliance based objective function and a displacement based one. In the dynamic case, written in the frequency domain, the two proposed objective functions include the viscoelastic material model (a Zener fractional derivative one) used to fill the design domain. The displacement criteria is developed using a general formula able to take into account as many degree of freedom as necessary. Finally, some applications based on beams and CubeSat-like structures are shown in this article. The proposed examples show that in both statics and dynamics, the optimization of a restrained design domain attached to an existing structure can improve its behavior: stiffness improvement or vibration reduction.

According to the development of the electric vehicle motor drives, a magnetic gear compound motor with small size, lightweight, non-contact, and high-power has a good development prospect in the new energy electric vehicle industry. A new dual-modulation magnetic gear compound motor (DMFMCM) with high torque, low torque ripple, and high mechanical strength is proposed in the paper. The topology and driving principle of DMFMCM are analyzed in this paper, and the finite elements analysis (FEA) is used to compare and analyze the DMFMCM and the conventional magnetic gear compound motor (CMGCM). Furthermore, the mathematical model of DMFMCM is established to achieve the decoupling of the three-phase voltage or current, and the mathematical model and FEA co-simulation is established to ensure the accuracy of the mathematical model. Finally, according to the principle of SVPWM controlled by id = 0, the paper simulates a PI-adjusted three-phase DMFMCM control system model. The result shows that the DMFMCM controlled by SVPWM has high stability, strong anti-interference ability and good speed regulation performance, thus meeting the development of electric vehicles.

In conjunction with mechanical joining processes. Mechanical joining processes play a key role for the realization of multi-material lightweight structures, which are essential with regard to environmental protection. However, joining of dissimilar high-strength materials is challenging due to the varying properties of the joining partners and due to their high flow stresses and often limited ductility. Thus, the evolution of established processes as well as the development of innovative and highly productive joining technologies are necessary. Requirements for a highly volatile production environment are versatility, flexibility, resilience and robustness. Within this contribution, current trends and innovations related to selected mechanical joining processes for enabling the material mix are outlined in order to point out opportunities to address these requirements in the future. In this context, joining using cold formed pin structures is presented as a promising approach for connecting dissimilar materials like metals to fibre-reinforced plastics. Furthermore, it is shown how the shear-clinching technology can be combined with a process-adapted application of locally limited heat treatment in order to promote the joinability and control the material flow during joining. A novel approach for reducing process forces and expanding process windows is the use of ultrasonic assistance for mechanical joining operations, which is demonstrated by the example of a nut staking process with superimposed high frequency oscillation. As concerns the widely used self-piercing riveting technique, current research activities relate not only to the further development of the joining process itself, for example by combining self-piercing riveting and tumbling, but also to the use of new rivet materials like high strain hardening stainless steels. In addition, the evolution towards mechanical joining 4.0 against the background of data-based process control in conjunction with of mechanical joining processes is also subject of the considerations.

Smart parts providing information to the user thanks to an embedded device are an important step toward the industry 4.0. Magneto-strictive properties of steel are well known and thin strips could be embedded in paramagnetic host part to ensure their structural control. Through this study, the feasibility of smarts parts realized by insertion of thin steel strip during aluminum host part manufacturing is more asserted. This study presents a configuration to embed thin steel strip inside massive part realized by Wire Arc Additive Manufacturing (WAAM). This configuration is used to find a correct steel strip − welding torch offset enabling a correct bonding between the deposited bead and the strip without causing any deterioration to the strip. Thickness maps of these strips realized through X-ray tomography allow to evaluate the deterioration of the strips. Scanning electron microscopy is used to evaluate the strength of the bonding through the thickness of the bimetallic interface realized between the steel strip and the aluminum bead. A good bonding between a thin steel strip and a thick part in aluminum alloy thanks to arc welding is obtained. The thickness difference between the two entities welded together represent a ratio of 10, which is 3 times bigger than the previous work reported in literature. Steel to aluminum welding is a challenging research topic and thin to thick element welding as well. This paper address both of these topics together and is a step toward smart metallic part manufacturing.

In this paper, a multi-field coupling simulation model, including the motor, shaft, and pump, is established to analyze the motor's influence and the shaft on the pump's operating status. First of all, different forms of simulation calculation models are established according to each device's characteristics. Then, the Predictor-Corrector Newmark-β method (PC Newmark-β method) is used to calculate the operating status of the motor, shaft, and pump under mutual influence. Finally, the validity of the simulation model is verified by comparing the experimental data. The results show that the centrifugal pump, shaft, and motor should be viewed as a complete system to analyze. The torque and speed of different equipment are interrelated and influenced. In addition, the dynamic characteristics of the shaft will also cause the fluctuation of the pump's operating speed. The fluctuation of the centrifugal pump impeller's rotational speed further affects the characteristics of the pressure pulsation on the wall of the centrifugal pump, which is finally reflected in the vibration characteristics of the pump casing.

The web crossed truss boom is one of the commonly used truss boom structures of crawler cranes. However, the existing calculations fail to consider the limiting effect of the web members' bending resistance on the chord members, and cannot give full play to the load-bearing capacity of the existing structure. This paper takes the top section of the Crawler crane truss boom as the research object. The single-span truss theoretical model is established according to Timoshenko's elastic stability theory. And the theoretical critical load of the variable cross-section boom is obtained with full consideration of the limitation of the web member's bending resistance on the chord members. The finite element method simulation model is compared and verified. Compared with a large number of simulation experiments and theoretical calculations, it can be concluded that the theoretical calculations in this article are highly consistent with the simulation results, verified the assumptions that the web members' bending resistance help to improve the bending resistance of the chord members, and this will provide certain reference to the engineering designers.

Double-layer composite water-lubricated bearing is a new type of water-lubricated bearing which can integrate the good damping performance of low elastic under-layer bush and good tribological performance of plastic layer bush. This paper analyzes its elastohydrodynamic lubrication performance by fluid–structure interaction (FSI) method, and studies the effects of eccentricity ratio, rotational speed, elastic modulus distribution and thickness distribution of bearing bush on its lubrication performance. Results show that the lubrication performance of double-layer bearing is more like that of plastic bearing. As rotational speed and eccentricity ratio increase, the maximum water film pressure, the load carrying capacity and the maximum bush deformation increase significantly. As the elastic modulus of the low elastic under-layer bush decreases, the total bush deformation increases significantly, but the load carrying capacity decreases slightly. The bush thickness distribution influences the deformation distribution of both low elastic under-layer bush and plastic layer bush, but have little impact on the total bush deformation and bearing lubrication performance.

Shore-side container cranes (SCC) are widely used in ship loading and unloading. However, the SCC is often damaged by the seismic wave shock. In seismic response analysis, the setting of damping coefficients has a large impact on the accuracy of the calculation results. In order to better design the SCC mechanical performance, the improved damping coefficient calculation method is proposed. The results of the simulation and the experiment are compared under the different seismic conditions. The results show that the influence of the damping coefficient calculation method on the SCC seismic response increases with strengthened seismic intensity. When the peak acceleration is small, the simulation results under different damping coefficients are almost the same and are close to the experiment values. When the peak acceleration is large, only the error between the simulation results obtained by the improved method and the experimental values is less than 5%. It is thus concluded that the improved damping coefficient calculation method is accurate and reliable.

Experiments of a steel sphere oblique impact with a rubber cushion have been proceeded to research the variation laws of the specific energy at interface. The contact surfaces above and under the rubber cushion can be recorded with a thin carbon paper. The parameters of deformation volume and specific energy are analyzed by the developed formulas in different cases of the impact angle, cushion thickness, drop height and sphere diameter. It is found that the deformation volume and related geometrical sizes decrease approximately exponentially with the impact angle, and the volume of the tangential moving part reaches a maximum at 50° or 60°. The variation laws of the specific energy absorption/dissipation in normal are similar to that of the axis length. The tangential specific energy can be divided into three main phases, the first two appear the states of slow increase and plateau, between of them a fluctuating peak exists at 30–40°. In final phase, the energy absorption shows sharp increase, but the energy dissipation first increases and then decreases. In addition, they increase linearly with the drop height and sphere diameter, and an optimum cushion thickness of 4 or 5 mm in the given cases.

Electromechanical braking system is the key way to improve the braking response ability of mine hoist. At present, the reliability research of electromechanical braking system is less. In order to further analyze and improve the reliability of electro-mechanical braking system, this paper adopts the reliability analysis method of electro-mechanical braking system based on fault tree and Bayesian network. Firstly, the fault tree of the electro-mechanical braking system is established, and then the fault tree is transformed into a Bayesian network, and the posterior probability, probability importance and key importance of each root node are inversely deduced. The diagnosis results show that the ball screw is the weakest link of the electro-mechanical braking system. Then the static simulation and fatigue life simulation of the ball screw are carried out for optimization, and the optimal model of the ball screw is determined. Finally, the electro-mechanical brake installed with the optimized ball screw is tested and analyzed. After the reliable performance test of the electro-mechanical brake, it is finally determined that the braking effect of the optimized electro-mechanical brake is stable.

In this paper, the combined effects of the characteristic size and concentration of inorganic fullerene-like tungsten disulphide nanoparticles (IF-WS2 NPs) or molybdenum disulphide nanoparticles (IF-MoS2 NPs) on the nonlinear dynamic behaviour of a gasoline engine crankshaft bearing subject to an arbitrary force torsor (effective applied force and moment vector) are theoretically and numerically investigated using the V. K. Stokes micro-continuum theory. These NPs are the most common additives for lubrication purposes due to their excellent tribological characteristics along with their effect on reducing friction and wear. It is assumed that the journal (crankshaft) currently made of a forged steel is rigid and the main bearing consists of a thin poroelastic liner made of low elastic modulus materials like Babbitt metals fixed in a stiff housing as defined by ASTM B23-00. The Krieger-Dougherty law is included in the proposed EHD model to account for the viscosity variation with respect to the volume fraction of nanoparticles dispersed in the base lubricant. On the other hand, the characteristic size of nanomaterials is introduced by a new material entity, denoted l, which is responsible for a couple-stress property. The Reynolds equation is derived in transient conditions and modified to account for the size of nanoparticles and the bearing-liner permeability property. For an arbitrary force torsor, the hydrodynamic pressure distribution, the squeeze film velocities, and the misalignment angular velocities are determined simultaneously by solving the discretized Reynolds equation and the equilibrium equations with the damped Newton-Raphson iterative method at each crank angle step. The crankshaft center trajectories in three sections of the main journal axis as well as the misalignment angles are deduced from the squeeze film velocities and the misalignment angular velocities by means of a Runge-Kutta scheme. According to the obtained results, the combined effects of the size and concentration of fullerene-like nanoparticles on the dynamic behavior of a compliant dynamically loaded crankshaft bearing operating with dynamic misalignment are significant and cannot be overlooked.

The low strength and large protrusion of the traditional dieless clinched joint hindered its application. To improve the mechanical properties of the dieless clinched joint, a novel dieless clinching process considering the limitation of the blank holder was proposed. The finite element model of the dieless clinching process was established by DEFORM-2D, the influences of the blank holder spring stiffness, the blank holder limit height, and the punch diameter on the mechanical interlock of the joint were analyzed, and the influence laws of blank holder spring stiffness and blank holder limit height on material flow and mechanical interlock were obtained. Then, the influence of these three die parameters and their interaction on the joint interlock were analyzed using the response surface method. The results show that the blank holder displacement plays a key role in the formation of mechanical interlock in the dieless clinching process. Reasonable limit height and spring stiffness of the blank holder can control the flow direction of materials, so as to improve the mechanical interlock and the strength of dieless clinched joints. It provides a new idea for improving the dieless clinching process.

After having determined the LPBF additive manufacturing parameters for the AlSi5Cu3Mg alloy by means of a design of experiment method, three tempers are studied on the manufactured test pieces: as built, direct aging and T6. The study reviews the impact of these three tempers on porosity assessment, microstructure and mechanical properties. It appears that the microstructures in the as built and direct aging tempers are often comparable to those of the AlSi7Mg0.6 and AlSi10Mg alloys which are used as references. However, a significant difference appears with the T6 temper, which does not show any change in porosity for the AlSi5Cu3Mg alloy, unlike the two other alloys. Moreover, due to a high density of type θʺ and/or θ′ fine precipitates, the T6 temper features a high yield strength but also an almost isotropic behaviour with good elongation. The analysis of the mechanical behaviour of the AlSi5Cu3Mg alloy in the three tempers is completed with an analysis of the strain hardening rate which is put into perspective with an EBSD analysis of the dislocation density, thus highlighting a close relationship between the microstructures (especially fine dendritic structures) and a high dislocation density. Lastly, a technical and ergonomic study is presented which compares the AlSi5Cu3Mg and AlSi7Mg0.6 alloys. Finally, we explain the interest of the T6 temper for the AlSi5Cu3Mg alloy after LPBF additive manufacturing.

The aim of this study is to identify simultaneously the thermal conductivity tensor and the heat capacity per unit volume of a bimaterial, whose heat conduction obeys Fourier’s law. This approach is validated by numerical simulation. The simulated temperature fields are obtained by the direct resolution of the heat conduction equation solved numerically with the help of finite element method formulation. To identify the parameters, an inverse method is developed by using the finite element model updating (FEMU) based on the Levenberg-Marquardt algorithm. This inverse finite element method approach allowed us to estimate the thermophysical parameters sought. We validated the numerical procedure by using noiseless temperature fields at different time and space steps and two types of material: an homogeneous and a bimaterial one. To be close to real conditions, the influence of the noise on the temperature fields is also studied and shows the efficiency of the inverse method. The results of this procedure show that the identified parameters are very less sensitive to the number of infra-red images varying from 40 to 80 and the number of elements ranging from 20 to 50 for a specimen size equals to 36.6 × 36.6 mm2.

Due to the great differences in mechanical properties between hard concretion and coal, the shearer drum cutting coal and rock containing hard concretion will inevitably lead to a series of problems, such as severe load impact, increased cutting specific energy consumption and low coal loading efficiency. Taking the cutting part of a thin coal seam shearer in service in the target mining area as the prototype, the mechanical models of shearer drum and rocker arm are established by using UG, and the discrete element model of coal wall with hard concretions is built by importing it into EDEM. The influence law of traction speed on coal loading rate, drum load and cutting specific energy consumption is analyzed, and the corresponding fitting relationship function is obtained. Taking the traction speed as the design variable, and the drum load, cutting specific energy consumption and coal loading rate as the comprehensive indicators, a multi-objective optimization function is established. The optimal solution is obtained by using NSGA II optimization algorithm, and the accuracy of the simulation is verified by experiments. This method has certain engineering significance for the reasonable selection of shearer traction speed.

Shear theory is the mainstream view to explain the cutting process. Because of the complexity of the cutting process, it is still difficult to explain and predict the physical phenomena in the cutting process accurately by shear theory. While some physical phenomena can be well explained by fracture theory. At the same time, with the development of fracture theory, fracture phenomenon in cutting process has attracted scholarsattention again. Therefore, the early development and current application of fracture theory in the study of cutting process are reviewed in detail. The research results and key points of fracture theory in cutting process are summarized. The development direction of fracture theory in the cutting process is briefly discussed. It is considered that the integration of fracture theory and shear theory is an effective way to study cutting mechanism, and the cutting process is divided into six stages in order to integrate fracture and shear theory.

This article presents the results of comparative studies of existing methods to calculate the inductance of dynamic and static single-phase reactors of arc extinguishing by double-rod and armored magnetic circuits with non-magnetic gaps in terms of the geometric parameters of the device. There are proposed expressions to correct the determination of the effective area of the winding of reactors by the shunting magnetic flux. On the basis of numerical calculations, the significant influence of the correct calculation of the effective area of the reactor winding by the shunt magnetic flux on the result of calculating the inductance is shown, it undoubtedly affecting the accuracy of the operation of both many digital devices of existing substations in particular, and new digital substations being introduced in general. It was also found in the work, that carrying out the correct calculation will improve both electrical characteristics of the device, and technical economic indicators of capacitive current compensation systems as part of digital substations, when setting the inverse problem of determining the geometric dimensions of the electrical part of the reactor according to the known inductance value, which depends and is calculated on the parameters of the given network, including capacitive currents.

Numerical investigation was carried out to study the heat transfer performance for a high-speed rotating cylindrical surface subjected to single row array round jets impingement, under a very small gap spacing. Various parameters that affect heat transfer, such as the fluid density, flow velocity and Nusselt number distributions of the radius clearance were studied based on varied nozzle to target surface spacing H and mass flow rate. It has been found that the fluid density was a dominant factor and the velocity was the secondary factor for the gas jet heat transfer performances. The overall heat transfer was improved with a reduction in the number of nozzles, for given inlet mass flow rate boundary conditions. The decrease of H/di (di, nozzle diameter) may have positive or negative effects on the heat transfer performance from the impingement surface. Reducing the radius gap H, for a certainty, increases the average density of the fluid in the clearance, which is desirable in applications that enhance heat transfer performance. But when the radius gap (H) is small enough, increasing di may have a negative impact on heat transfer.

A dynamic model of swing system of bridge-type ship unloader is established by considering the elastic factor of wire rope in this paper. Based on this model, an improved Negative Zero Vibration (NZV) shaper with optimal control parameters of variable rope length system is proposed to restrain the swing of grab. Then the control effects, influence of elasticity factor and parameter sensitivities are analyzed based on numerical simulation. The results show that the proposed control strategy can reduce the working cycle time of the grab ship unloader about 11% when considering the elastic factor of the wire rope, and the grab's maximum residual swing angle decreases by 67% when discharging at full load, and decreases by 79% when taking the cargos at empty load. This implies that the improved NZV control method provides better swing angle control performance and shorter operation time compared with the Zero Vibration (ZV) and Zero Vibration and Derivative (ZVD) methods. Moreover, elastic rope model can improve the swing angle control effect of grab based on the proposed control strategy compared with rigid rope model. The parameter sensitivity analysis displays that the grab's maximum residual swing angle by using the improved NZV method is sensitive to the change of the grab's center of gravity, and this angle is more sensitive to the wire rope diameter deviation compared with the elastic modulus deviation.

The wear of the piston ring-cylinder system is inevitable in the operation of the internal combustion engines (ICEs). If wear exceeds the maximum, the piston ring-cylinder system will be failure. A novel wear assessment model is proposed based on the support vector regression, and the fuzzy uncertainty is modeled to describe the random behavior under small sample. To verify the proposed model, the sample data of cylinder liner wear is applied. For best results, the particle swarm optimization (PSO) algorithm is used to optimize the model parameters. A back propagation neural network (BPNN) is employed to verify the effectiveness of the proposed model. The results show that the novel support vector regression has better prediction accuracy than other methods for cylinder wear in this paper, the proposed model can evaluate the cylinder liner wear of the ICEs effectively. The work provides a technical support for evaluating the service performance of the piston ring-cylinder liner and a reference for regular maintenance of the ships.

To improve the quality and energy indicators on the front plow in front of the housings, the angle axes are installed in the form of a triangular wedge. The purpose of the study is to substantiate the parameters of the angle-lift of the front plow, which provides high-quality performance of the technological process according to agrotechnical requirements with the lowest energy costs for smooth, rowless plowing. The research uses the laws and rules of theoretical mechanics, mathematical statistics, mathematical planning of experiments, and methods of strain measurement, as well as the methods given in existing regulatory documents. Based on the study of the process of interaction of the carbon monoxide with the soil, analytical dependences are obtained that allow us to determine the parameters of the carbon monoxide. According to the results of theoretical and experimental studies, it was found that the required quality of tillage with a front plow following the established agrotechnical requirements with minimal energy consumption is provided at the height of 22 cm, a length of 27 cm, a wing angle of 32° and an angle of inclination of the side face of 36°.

In the conditions of high-speed processing of parts of complex configuration, with a large end and longitudinal length, from hard-to-work steels and alloys, it is difficult to ensure the wear resistance of the cutting tool in the aisles of one technological passage. To ensure the appropriate quality indicators of the surface layer, it is impossible to replace a worn-out cutting tool. In connection with the above, the problem of ensuring the operability (wear resistance) of the cutting tool is acute. The results of theoretical and experimental studies of contact phenomena in blade cutting based on the thermodynamics of non – equilibrium processes and from the standpoint of self-organization of the tribosystem are presented. the developed thermodynamic model of blade processing with variable cutting modes (non-stationary) allows to minimize the wear of the cutting tool and generally increase production efficiency by accelerating the drive of the main movement of the metal-cutting machine.

The process of thermo-mechanically controlled rolling in the conditions of Steckel mill of Ferriera Valsider plant was developed for the first time for hot-rolled coils in the sizes of 12 mm × 1510 mm from steel of X65 grade for further production of electric welded pipes according to the API-5L standard. The developed process provides carrying out of the roughing-rolling in two stages to facilitating the forming of a smaller austenite grain and therefore more dispersed and homogeneous inherited ferrite structure in the finished rolled product. At the implementation of the process, the holddown of the temperature at the desired level at 1780 Steckel rolling mill has been carried out by adjusting the number of burners in furnace coilers. The process of controlled air cooling of rolled coils to a temperature of 400°C after winding in the developed technology for Steckel’s mill condition of Ferriera Valsider plant is applied for the first time that allowed to reduce the thickness of the air scale layer and to improve the surface quality. The performed research has been allowed to evaluate the feasibility of the operating equipment and to determine the possibility of coils fabrication related to the nowadays world requirements and satisfied to the demand of European electricwelded pipes manufacturers.

In recent years, the interest in low-pollution and high-efficiency heat engines has been increasing due to the growing awareness of environmental protection, and power generation at relatively low temperatures, such as use of exhaust heat and sunlight, has been attracting attention. Compared with other heat engines, Stirling engine is very important because it can be driven by any heat source at low temperatures, such as exhaust heat, and it does not emit exhaust gas. In order to realize a more efficient Stirling engine, it is essential to design a heat exchange system that is suitable for each component. Performance measurement and analysis on a new mesh regenerator material at low temperature difference using a 2-piston alpha-type 3-kW Stirling engine, NS03T are carried out. Mesh sheets developed for high performance Stirling engines can be designed with CAD and CAM technologies by etching process. For this study, M5 and M7 mesh sheets which are thin sheets of stainless steel with square holes in a grid arrangement, are used. With nitrogen and helium as the working fluid, the engine performance is measured by changing the charge pressure, heating temperature, and engine speed to clarify the flow resistance and heat transfer characteristics of the M5 and M7.

This research paper provides a method for calculating airborne sound insulation by encloses from volumetric-block buildings. The choice of the most suitable construction solution for the technical condition of objects at the design stage for building elements should primarily provide insulation from sound and a safe mode inside buildings, in which protection conditions in the combination of energy efficiency and stability should be taken into account, as well as competent decisions and its impact on the construction process buildings. Numerous scientific studies show the negative effect of sound on human health by the occurrence of various diseases such as cognitive impairment of the fetus in reproductive people, sleep disturbances, tinnitus, irritation, and dysfunction of some human organs. Therefore, sound exposure should be considered a source of inconvenience and a source of harm to human health. Sound waves collide with the surfaces of enclosing structures, causing them to vibrate and transmit the negative effects of the air around them in adjoining rooms, in which, from the point of view of regulatory requirements, in many cases, it does not meet the requirements, since comfort also depends on the design and sound insulation of the volumetric-block buildings. Many of these problems are easily solved at the design stage by choosing the right design solution and calculating the soundproofing qualities of the enclosing structures. In particular, one of the main tasks at the design stage is the development of structural solutions for internal enclosing structures that have a relatively small mass that allows reducing the load on the supporting structures of the building and plummets the material consumption of construction. At the same time, it is necessary to ensure compliance with the regulatory requirements for the isolation of airborne sound of enclosing structures.

Carbon nanomaterials reinforced composite materials have been broadly utilized in manufacturing engineering due to improved thermal resistivity, reduced weight, and other improved mechanical properties. This article highlights the drilling experimentation of zero-dimensional (0-D) Carbon nano onion (CNO) reinforced polymer composite. For this, three drilling constraints was considered viz., spindle speed, feed rate, and weight % of nanomaterial reinforced. The objective is to achieve the desired value of generated drilling forces such as Torque (Nm) and Thrust Force (N) during the machining procedure of developed composite samples. The Multiobjective-Particle Swarm Optimization (MOPSO) is utilized to achieve optimal results from the multi-decision criterion for the Machining performance. Exploiting this optimization process, non-dominated solutions were obtained, and the Pareto front was identified. Practical applications for the discovered relationships include using Grey relation analysis (GRA) to extract the most relevant finding from the Pareto Front space of optimal solutions. Using the GRA, the optimum solution was found: Spindle Speed of 1000 RPM, Feed Rate of 100 mm/min, and CNO weight percentage of 0.5. After this, a confirmation test was performed, the expected effects have been confirmed. The findings reveal that the proposed optimization module can be recommended for online quality and productivity control.

The article describes some aspects of the research and applied works, which the authors carried out to expand the scope of application in the study of rock strength indicators in the laboratory of KuzSTU (Prokopyevsk branch) on a complex equipment. It consists of an extreme deformation chamber and a volumetric compression chamber. It describes the disadvantages of the volumetric compression chamber. The disadvantages have been eliminated by using a special device for fixing the sample when descending into the volumetric compression chamber. The article also gives the description of the operation of a volumetric compression chamber with the possibility of testing rock samples for a breakage under the volumetric compression. The first test results are presented.

This study aims to optimize the distributions of groove textures in a journal bearing to reduce its friction coefficient. Firstly, A lubrication model of a groove textured journal bearing is established, and the finite difference and overrelaxation iterative methods are used to numerically solve the model. Then, the friction coefficient is adopted as the fitness function and the groove lengths are optimized by particle swarm optimization (PSO) algorithm to evolve the optimal distributions. Furthermore, the effects of eccentricity ratios and rotary speeds on optimal distributions of groove textures are also discussed. The numerical results show the optimal distributions of groove textures are like trapeziums under different eccentricity ratios and rotary speeds, and the trapeziums become slenderer with increasing of eccentricity ratios. It is also found that the reductions of friction coefficients by optimal groove textures are more significant under lower eccentricity ratios. Briefly, this study may provide guidance on surface texture design to improve the tribological performance of journal bearings.

Solid end mill with a toroidal forming section are the most productive solutions in the field of processing difficult-to-process materials. The process of forming the cutting geometry of such cutters is performed on grinding machines with CNC with the use of abrasive grinding wheels. The formation of the cutting edge on the toroidal section is carried out by discrete movements of the working bodies of the machine in accordance with the control program. The disadvantage of the stepper drive used in CNC machines is the limited discreteness of the described trajectory resulted in the loss of accuracy when forming radius, arc, spherical and toroidal sections. Loss of accuracy in the formation of elements of the working geometry of a solid end mill can negatively affect the tool life, and the structural strength of the joints of the transition of working surfaces. The study is aimed at identifying the necessary and sufficient number of points that describe the spatial shape of the cutting edge with acceptable loss of accuracy.

The article proposes a model of the ultimate stress state of the material of the coated tool cutter. It is found that with an increase in the fracture toughness of a tool in connection with the material ductility the machining accuracy deteriorates due to arising elastic-plastic vibrations of the tool cutter. In case when no ultimate stress state is reached, that is, a tool operates in the elastic region, then an alternating stress distribution diagram is realized for the tool cutter at the beam approximation. Therefore, in addition to the frictional vibrations, arising from the interaction between the tool cutter and a workpiece, the elastic vibrations can arise, which affects the machining accuracy and the service life of the coated tool cutter. The use of coatings makes it possible not only to increase the wear resistance of cutting tools, but also to transform the stress distribution diagrams of the normal σN and tangential τγ contact stresses acting on the rake face of the cutting tool. In particular, it is possible to control the length of the total contact area between the chips and the tool rake face.

The article studies the work of a water jet pump (ejector), influence of the mixture characteristics and pipe length on the energy parameters of the ejector system. The relevance of the topic is associated with the active use of ejectors in the modern world in various areas, including in hydraulic structures. Frequent use of ejectors is ensured by high reliability, simplicity of design and maintenance. The purpose of this work is to study the operation of the ejector, the energy characteristics of the flow and the influence of the characteristics of the transported two-phase flow. The calculation of the real practical problem of selecting an ejector for lifting and transporting solid particles is given. The values of the density of the transported mixture and the length of the transport pipes are selected as variable indicators. The analysis of the calculation shows that taking into account the energy characteristics of the flow when selecting the components of the ejector system is very important, and the density of the transported mixture affects the efficiency of the system.

At present, LED lighting is gradually replacing the traditional lighting and becoming the fourth generation of light source. In the process of LED lighting, a large part of electric energy is converted into heat energy. If it can not dissipate heat in time, the device efficiency will be reduced or even damaged. Therefore, the heat dissipation problem of LED needs to be solved. By testing and recording the working temperature of the existing LED lighting radiator in different positions, the performance of the radiator was compared and tested. The experiment shows that the radiator works best when the light source is downward, and the temperature difference between the top and the bottom of the radiator is the smallest in this case, and the temperature at the top of the radiator is higher than that at the bottom in the working process. When the position of the LED lighting radiator changes, the heat dissipation performance of the top and bottom of the radiator changes.

This study demonstrates theoretical approaches useful for practical determination of machining conditions affecting machined surface topography in filleted end milling. Tool orientation is investigated in particular. There are dominant processing parameters' optimizations from various perspectives, whereas a few comprehensive strategies have been proposed to determine machining conditions in filleted end milling. It is also practically scarce to discover the optimization strategy taking path interval determination as the theoretical fountainhead. In this study, theoretical approaches were described to determine machining conditions affecting machined surface topography in filleted end milling. After geometrical description was arranged to model multi-axis filleted end milling, multi-layer approach and the other computable parameters were proposed to obtain decent surface topography generated in filleted end milling. The analytical example focusing on tool orientation was provided with discussion. As a result, some characteristics of theoretical approaches were revealed with the visual evidences. Finally, optimal tool orientation will be arranged based on the findings.

Currently, among the most popular computational fluid dynamics software packages are commercial CFD packages – ANSYS CFX, ANSYS Fluent, STAR-CCM+ and several others. In contrast to the above-mentioned commercial CFD packages, there is an OpenFOAM, a non-commercial, freely distributed, integrated platform for numerical modeling of solid-state mechanics tasks (including CFD tasks), and it is becoming more and more popular. In addition to being a non-commercial package, OpenFOAM also has open-source code, which allows users to write their own algorithms for solving highly specialized tasks. A comparison of ANSYS and OpenFOAM in the application to CFD problems of incompressible turbulent flow in this article is given by the example of jet pump calculation, which was tested in the Laboratory of Hydraulic Machinery of Peter the Great St.Petersburg Polytechnic University.

One of the most promising technologies for sea-wave energy conversion is the one based on the Oscillating Water Column (OWC) principle. The system is composed of two units, an open chamber that converts the sea water motion into an alternating air-flow, and a turbine driven by the latter. The alternating flow of air requires a turbine capable of maintaining the same direction of rotation. The Wells turbine represents the simplest and most reliable device for this purpose. It is a self-rectifying axial turbine characterized by a rotor with symmetric blades staggered at 90 degrees relative to the axis of rotation. The vast majority of experimental works on Wells turbines and OWC devices analyzed their performance from a global point of view, often under steady conditions, in order to evaluate the pressure drop through the rotor, the torque produced and thus the turbine efficiency. This paper presents an experimental analysis of the three-dimensional flow inside a Wells turbine which operates in a facility capable of reproducing the alternating air-flow typical of an OWC system. The investigation is based on local flow measurements using several probes in order to describe the non-stationary air-flow, both up- and down-stream of the rotor at different heights, along the span of the blade. The investigation, conducted on a high-solidity turbine, details the behavior of the flow field inside the machine, aiming to provide a detailed description that can guide the aerodynamic optimization of the entire system (chamber and turbine) for a better energy conversion.