Mechanical Engineering Problems Research Articles

An enhanced surrogate-assisted differential evolution for constrained optimization problems

The application of evolutionary algorithms (EAs) to complex engineering optimization problems may present difficulties as they require many evaluations of the objective functions by computationally expensive simulation procedures. To deal with this issue, surrogate models have been employed to replace those expensive simulations. In this work, a surrogate-assisted evolutionary optimization procedure is proposed. The procedure combines the differential evolution method with a $$k$$ -nearest neighbors (k-NN) similarity-based surrogate model. In this approach, the database that stores the solutions evaluated by the exact model, which are used to approximate new solutions, is managed according to a merit scheme. Constraints are handled by a rank-based technique that builds multiple separate queues based on the values of the objective function and the violation of each constraint. Also, to avoid premature convergence of the method, a strategy that triggers a random reinitialization of the population is considered. The performance of the proposed method is assessed by numerical experiments using 24 constrained benchmark functions and 5 mechanical engineering problems. The results show that the method achieves optimal solutions with a remarkably reduction in the number of function evaluations compared to the literature.

A novel generalized normal distribution optimizer with elite oppositional based learning for optimization of mechanical engineering problems

Abstract Optimization of engineering discipline problems are quite a challenging task as they carry design parameters and various constraints. Metaheuristic algorithms can able to handle those complex problems and realize the global optimum solution for engineering problems. In this article, a novel generalized normal distribution algorithm that is integrated with elite oppositional-based learning (HGNDO-EOBL) is studied and employed to optimize the design of the eight benchmark engineering functions. Moreover, the statistical results obtained from the HGNDO-EOBL are collated with the data obtained from the well-established algorithms such as whale optimizer, salp swarm optimizer, LFD optimizer, manta ray foraging optimization algorithm, hunger games search algorithm, reptile search algorithm, and INFO algorithm. For each of the cases, a comparison of the statistical results suggests that HGNDO-EOBL is superior in terms of realizing the prominent values of the fitness function compared to established algorithms. Accordingly, the HGNDO-EOBL can be adopted for a wide range of engineering optimization problems.

Modeling and calculation of the technological process of testing piston hydraulic cylinders with energy recovery

One of the most important problems of modern mechanical engineering is the energy efficiency of technological equipment and manufactured products. A separate issue in this series is the technology and means of testing finished product samples, including hydraulic machines. In this article, an original scheme of a test bench for piston hydraulic cylinders and a method of mathematical modeling of the process of its functioning, based on the application of the theory of volumetric rigidity of hydraulic systems, is proposed, which makes it possible to describe with high accuracy and reliability the processes occurring in the test system during its operation. The test efficiency coefficient is proposed, which makes it possible to evaluate and compare various test processes by the criterion of their energy efficiency. An example of a preliminary calculation of the functioning of the proposed stand is given.

Simulation of the testing process of reciprocating hydraulic cylinders with energy recovery

One of the most important problems of modern mechanical engineering is the energy efficiency of technological equipment and manufactured products. A separate issue in this series is the technology and means of testing finished product samples, including hydraulic cylinders, which can be carried out with passive or active energy recovery. The purpose of the work is to develop a test bench for piston hydraulic cylinders that provides recovery of part of the energy during the test, and at the same time the tests would take place in a mode as close as possible to the real conditions of their operation during their tests, as well as solving the problem of its modeling and calculation of the main functional parameters. In this article, a design scheme of a test bench for reciprocating hydraulic cylinders with active energy recovery and a method for mathematical modeling of the process of its functioning based on the application of the "theory of volumetric rigidity of hydraulic systems" is proposed, which makes it possible to describe with a high degree of accuracy and reliability the processes occurring in the test system during its operation. A scheme of a test bench for piston hydraulic cylinders with energy recovery is proposed. A mathematical model of the stand has been developed and an example of a preliminary calculation of its functioning is given. The proposed modeling method simplifies the modeling process and allows the use of numerical integration methods in calculations. The resulting mathematical model makes it possible to obtain rational parameters of the stand already at the design stage, without resorting to the need for expensive and labor-intensive field studies.

Application of Virtual Simulation Technology in Teaching Complex Engineering Mechanics Problems

Application of Virtual Simulation Technology in Teaching Complex Engineering Mechanics Problems

Experimental Evaluation of the Wet Steam Flow Electrification Effect on Its Dielectric Properties

It has been established that in order to study thermo- and electrophysical phenomena in wet steam turbines, studies of the wet steam flow volume charge effect on its dielectric and thermophysical properties have recently been carried out at A. Pidhornyi Institute of Mechanical Engineering Problems of the National Academy of Sciences of Ukraine. According to their results, it was established that the most representative electrophysical parameter, which allows to evaluate changes in the thermophysical properties of steam, which occur under the action of its own volume charge, is its dielectric constant. It is assumed that the value of the dielectric constant of an electrified steam can be significantly different from the value for a neutral steam, and a mathematical assessment of its possible change is made. It has been confirmed that the influence of electrophysical phenomena caused by the wet steam flow electrification is significant, but is not taken into account in the existing physical and mathematical thermodynamic models of the steam expansion process. It is proved that in order to clarify the main thermodynamic parameters and calculated characteristics of the electrified wet steam flow, it is necessary to determine how its dielectric constant changes. On the basis of the analysis, the relevance of experimental determination of the dielectric constant of a wet steam flow with a volume charge in order to obtain the dependence of its change on the temperature and pressure of the flow, as well as the density of the volume charge, is substantiated. To perform the research, a gas dynamic laboratory plant, which allows to obtain a wet steam flow with a volume charge, was used. The internal space of the flow part of a real wet steam turbine has a significant size and allows the formation of a flow with a volume charge of a complex spatial configuration and structure. It is emphasized that in the flow part of the plant of a small volume, in contrast to the turbine flow part, significant technical difficulties arise when organizing the conditions for the occurrence of a wet steam flow with a volume charge. Taking this into account, at the first stage, it was decided to conduct a study of a steam flow with a volume charge flowing into the atmosphere in a laboratory room with a sufficient volume to form its spatial structure. To estimate the value of its dielectric constant, the inductive method (L-method) of determining dielectric properties, in which the substance under study is introduced into the inductive solenoid cell, was chosen. Experiments were conducted and, according to the obtained data, it is possible to make a preliminary assessment of the change in dielectric constant in the presence of a volume electric charge in the steam flow

IMPROVING THE PROCESS OF PROCESSING HOLES WITH DRILLS

"One of the urgent problems of mechanical engineering is the processing of holes, which are subject to high requirements for the accuracy of size, shape and location. Most often, hole processing is carried out with the help of rod measuring tools. This is due to their following advantages: relatively high productivity, low costs for pre-production. The quality of the machined holes is determined mainly by the accuracy of the cutting tools, machines and accessories used. The drilling process with existing drills takes place under severe cutting conditions. The magnitude of the front angle on the transverse edge is very unfavorable. For standard spiral drills, the front angle γ on the transverse edge is up to minus 57–60. In view of this, on the transverse edge, instead of cutting, there is a crumpling, squeezing and scraping of metal. When drilling holes with existing drills, the transverse edge of the drill perceives up to 80 % of the axial force, i.e. the resistance to axial feed is created by the contact area of the transverse edge with the workpiece. The specified working conditions of the transverse edge significantly worsen the processing conditions and the quality of the treated hole. To eliminate the transverse edge, a new design of a spiral drill is proposed – a two-vertex spiral drill without a transverse edge, preliminary patent of the Republic of Kazakhstan № 19559. The elimination of the transverse edge on the drill allows you to dramatically reduce the heating and wear of the drill during the cutting process, increase the durability of the drills. The analysis of the results shows that the accuracy of the diametrical dimensions of the holes after processing with two-vertex spiral drills increased by 1, 2 quality compared with spiral drills; roughness decreased by 1, 2 classes. Keywords: spiral drill, jumper, sharpening, durability, accuracy, productivity "

Teaching Reform of Double-center & Three-cycle Hybrid Mechanical Specialty

The ability of college students to discover, propose and solve engineering problems in machinery has become an essential part of a contemporary college education. Therefore, the teaching reform focusing on cultivating College Students’ ability to propose and solve engineering problems has become an essential part of a college education. Taking mechanical students as an example, this paper constructs a teaching content and method with “students” and “theory, engineering” as the double centres, combined with “pre-class”, “in-class” and “after class”, in which the teacher put forward the relationship between curriculum knowledge points and mechanical engineering problems, guide students to discover actively, learn and apply curriculum knowledge points, and put forward practical solutions to engineering problems in combination with mechanical engineering related issues. To achieve the goal of teaching engineering problems based on theoretical knowledge and practical operation, we should combine the “Internet plus” modern teaching tools to create “Online & Offline” mixed interactive courses and high-quality curriculum resources, forming the circular multi-dimensional closed-loop teaching mode of “student, theory, engineering” cycle, “pre-class, during-class, after-class” cycle and “before class test, instruction, after class test” cycle, which the students’ ability to master knowledge points in the teaching process.

Unique Fixed Point Results and Its Applications in Complex-Valued Fuzzy b -Metric Spaces

The goal of this paper is to extend the concept of complex-valued fuzzy metric space to complex-valued fuzzy b -metric spaces and to discuss various existence results for fixed points to ensure their existence and uniqueness. To demonstrate the viability of the proposed strategies, a nontrivial example is used. Finally, applications to integral equations and initial value problems in mechanical engineering are discussed to demonstrate the superiority of the obtained results.

A novel multi-objective optimization method with local search scheme using shuffled complex evolution applied to mechanical engineering problems

PurposeIn this work, the multi-objective optimization shuffled complex evolution is proposed. The algorithm is based on the extension of shuffled complex evolution, by incorporating two classical operators into the original algorithm: the rank ordering and crowding distance. In order to accelerate the convergence process, a Local Search strategy based on the generation of potential candidates by using Latin Hypercube method is also proposed.Design/methodology/approachThe multi-objective optimization shuffled complex evolution is used to accelerate the convergence process and to reduce the number of objective function evaluations.FindingsIn general, the proposed methodology was able to solve a classical mechanical engineering problem with different characteristics. From a statistical point of view, we demonstrated that differences may exist between the proposed methodology and other evolutionary strategies concerning two different metrics (convergence and diversity), for a class of benchmark functions (ZDT functions).Originality/valueThe development of a new numerical method to solve multi-objective optimization problems is the major contribution.

A new hybrid artificial hummingbird-simulated annealing algorithm to solve constrained mechanical engineering problems

Abstract Nature-inspired algorithms known as metaheuristics have been significantly adopted by large-scale organizations and the engineering research domain due their several advantages over the classical optimization techniques. In the present article, a novel hybrid metaheuristic algorithm (HAHA-SA) based on the artificial hummingbird algorithm (AHA) and simulated annealing problem is proposed to improve the performance of the AHA. To check the performance of the HAHA-SA, it was applied to solve three constrained engineering design problems. For comparative analysis, the results of all considered cases are compared to the well-known optimizers. The statistical results demonstrate the dominance of the HAHA-SA in solving complex multi-constrained design optimization problems efficiently. Overall study shows the robustness of the adopted algorithm and develops future opportunities to optimize critical engineering problems using the HAHA-SA.

Synchronous properties of the friction phenomenon

The phenomenon of frictional slipping and sticking is one of crucial problems in mechanical engineering. This paper is focused on the numerical analysis of vibrations induced by friction in oscillator model which assumes an influence of the normal degree of freedom on the friction force. Analysis of Poincare maps, time courses and corresponding spectrum of Lyapunov exponents of the proposed three degrees of freedom dynamical system is demonstrated. It is revealed that the friction force, acting on the main slider, reflects dynamic behavior of the system response, i.e., some synchronous correlation between them is observed, even in the range of hyperchaotic behavior of the system, characterized by two positive Lyapunov exponents. On the other hand, an interesting effect of the coexistence of irregular friction force at the contact point of the frictional brush and ground surface with the regular response of the system in the quasi-periodic regime is reported.

Immersed body motion: near-bottom added mass effects

The presence of a solid boundary can cause a substantial increase in added mass due to a solid body movement in the fluid. If the body is very close to the boundary, the added mass increases at an even greater rate. The added mass can be of considerable importance in many dams and hydropower, water/ocean, civil and mechanical engineering problems; furthermore, it has an important effect on the dynamics of the vibrating body in the fluid. The principal aim of this paper is to define a novel model to properly evaluate the near-bottom effects of the added mass and to investigate the instantaneous pressure field due to a body movement that changes the thickness of a compressible thin fluid film close to a solid boundary. The body movement can be due to the application of an external force according to Newton's law. This phenomenon is studied theoretically in this paper, and a hydrodynamic model able to compute the instantaneous pressure field in the thin fluid film is drawn out. The fluid film thickness variation, producing compression and decompression waves, tends to reduce the mean body displacement due to external forces, but it generates both high-frequency fluctuations in body force and in body displacements. For the first time, this novel study provides the near-bottom added mass and justifies the strong body accelerations measured in the laboratory experiments that have not been evidenced in the theoretical studies in the known literature.

Solution to inverse natural convection problem using experimental data

Inverse problems arise in a wide range of practical systems and processes and, thus, form an important and well-known area of research in mathematics and physical sciences. The basic nature of an inverse problem is mathematically ill-posed and, as such, finding a unique, accurate, solution is challenging. A prime example of inverse problems in mechanical engineering is the inverse heat transfer problem where the desired solution is known and the boundary and initial conditions, or even material properties, are not. While the heat conduction problem has attracted the bulk of research due to its generally linear governing physics, inverse heat convection presents a greater challenge. The inclusion of fluid mechanics and the nonlinear nature of momentum and energy equations, combined with the previously mentioned ill-posed nature of the inverse problem, presents a challenging research topic. In this paper, a search-based inverse heat convection methodology, developed earlier, is tested against experimental data. The problem considered is a wall plume flow generated by a heat source, such as an electronic component or a fire, located on a vertical surface. This method shows that by measuring the temperatures at a limited number of points downstream of the heat source, the heat input and location of the source can be estimated within an acceptable range of accuracy. This paper continues the earlier work by including experimental data in the prediction of heat source strength and location. It is shown that the methodology introduced earlier is quite robust and can be used for a variety of important practical applications.

Preface

We are pleased to introduce the Proceedings of the XV International Scientific and Technical Conference “Applied Mechanics and Systems Dynamics” (AMSD-2021) organized by the Omsk State Technical University and held on November 9-11, 2021.The object of the scientific and technical conference "Applied Mechanics and Systems Dynamics" is the analysis of the current state, trends and prospects for the development of applied mechanics and system dynamics with the aim of improving technology and production and creating new- generation equipment.The conference addresses topical issues of development and research on the problems of mechanical engineering, strength and dynamics of mechanical systems.List of International Program Committee, Organizing Committee, Organizing Institutions are available in this pdf.

Starling murmuration optimizer: A novel bio-inspired algorithm for global and engineering optimization

This paper presents a novel bio-inspired algorithm inspired by starlings’ behaviors during their stunning murmuration named starling murmuration optimizer (SMO) to solve complex and engineering optimization problems as the most appropriate application of metaheuristic algorithms. The SMO introduces a dynamic multi-flock construction and three new search strategies, separating, diving, and whirling. The separating search strategy aims to enhance the population diversity and local optima avoidance using a new separating operator based on the quantum harmonic oscillator. The diving search strategy aims to explore the search space sufficiently by a new quantum random dive operator, whereas the whirling search strategy exploits the vicinity of promising regions using a new operator called cohesion force. The SMO strikes a balance between exploration and exploitation by selecting either a diving strategy or a whirling strategy based on the flocks’ quality. The SMO was tested using various benchmark functions with dimensions 30, 50, 100. The experimental results prove that the SMO is more competitive than other state-of-the-art algorithms regarding solution quality and convergence rate. Then, the SMO is applied to solve several mechanical engineering problems in which results demonstrate that it can provide more accurate solutions. A statistical analysis shows that SMO is superior to the other contenders.

Intelligent Detection of Steel Defects Based on Improved Split Attention Networks.

The intelligent monitoring and diagnosis of steel defects plays an important role in improving steel quality, production efficiency, and associated smart manufacturing. The application of the bio-inspired algorithms to mechanical engineering problems is of great significance. The split attention network is an improvement of the residual network, and it is an improvement of the visual attention mechanism in the bionic algorithm. In this paper, based on the feature pyramid network and split attention network, the network is improved and optimised in terms of data enhancement, multi-scale feature fusion and network structure optimisation. The DF-ResNeSt50 network model is proposed, which introduces a simple modularized split attention block, which can improve the attention mechanism of cross-feature graph groups. Finally, experimental validation proves that the proposed network model has good performance and application prospects in the intelligent detection of steel defects.

Primena Dingo optimizacionog algoritma (DOA) na rešavanje kontinualnih problema u inženjerstvu

In the current research, problems in engineering are becoming more and more prominent. One of the classes of engineering problems in engineering design problems, where a set of variables is calibrated in order for the optimization function to have a minimal or maximal value. This function considers energy efficiency, cost efficiency, and production efficiency in engineering design. One of the ways such problems are solved is metaheuristics. In this paper, we demonstrate how Dingo Optimization Algorithm (DOA) can be used to solve certain optimization problems in mechanical engineering. Firstly, a brief review of the DOA and its biological inspiration is given, along with the most important formulae. The pseudo-code for this algorithm was written using MATLAB R2020a software suite. Dingo Optimization Algorithm (DOA) was used to optimize engineering problems, such as pressure vessel optimization, stepped cantilever beam, car side-impact, and cone clutch optimization. The results presented in this paper show that the DOA can produce relevant results in engineering design problems.

Adaptive heterogeneous particle swarm optimization with comprehensive learning strategy

This paper proposes an adaptive heterogeneous particle swarm optimization with a comprehensive learning strategy for solving single-objective constrained optimization problems. In this algorithm, particles can use an exploration strategy and an exploitation strategy to update their positions. The historical success rates of the two strategies are used to adaptively control the adoption rates of strategies in the next iteration. The search strategy in the canonical particle swarm optimization algorithm is based on elite solutions. As a result, when no particles can discover better solutions for several generations, this algorithm is likely to fall into stagnation. To respond to this challenge, a new strategy is proposed to explore the neighbors of the elite solutions in this study. Finally, a constraint handling method is equipped to the proposed algorithm to make it be able to solve constrained optimization problems. The proposed algorithm is compared with the canonical particle swarm optimization, differential evolution, and several recently proposed algorithms on the benchmark test suite. The Wilcoxon signed-rank test results show that the proposed algorithm is significantly better on most of the benchmark problems compared with the competitors. The proposed algorithm is also applied to solve two real-world mechanical engineering problems. The experimental results show that the proposed algorithm performs consistently well on these problems.

Strength and Service Life of a Steam Turbine Stop and Control Valve Body

The stability of operation of steam turbines depends (along with other factors) on the reliable operation of their steam distribution systems, which are based on stop and control valves. This paper considers the strength of the elements of the K-325-23.5 steam turbine valves, in whose bodies, after 30 thousand hours of operation, cracks came to be observed. Previously determined were the nature of gas-dynamic processes in the flow paths of the valves and the temperature state of the valve body in the main stationary modes of operation. To do this, a combined problem of steam flow and thermal conductivity in stop and control valves was solved in a three-dimensional formulation by the finite element method. Different positions of the valve elements were considered taking into account the filter sieve. The assessment of the thermal stress state of the valve body showed that the maximum stresses in different operating modes do not exceed the yield strength. Therefore, the assessment of the creep of the valve body material is important to determine the valve body damage and service life. Modeling the creep of the stop and control valves of the turbine was performed on the basis of three-dimensional models, using the theory of hardening, with the components of unstable and steady creep strains taken into account. The creep was determined at the maximum power of the turbine for all the stationary operating modes. The maximum calculated values of creep strains are concentrated in the valve body branch pipes before the control valves and in the steam inlet chamber, where in practice fatigue defects are observed. However, even for 300 thousand hours of operation of the turbine (with a conditional maximum power) in stationary modes, creep strains do not exceed admissible values. The damage and service life of the valve bodies were assessed by two methods developed at A. Pidhornyi Institute of Mechanical Engineering Problems of the NAS of Ukraine (2011), and I. Polzunov Scientific and Design Association on Research and Design of Power Equipment. (NPO CKTI) – 1986. The results of assessing the damage and the turbine valve body wear from the effects of cyclic loading and creep of the turbine in stationary modes for 40, 200 and 300 thousand hours show that the thermal conditions of the body in the steam inlet chamber are not violated (without taking into account possible body defects after manufacture). The damage in valve body branch pipes after 300 thousand hours of operation exceeds the admissible value, with account taken of the safety margin. At the same time, the damage from creep in stationary operating modes is about 70% of the total damage. The maximum values of damage are observed in the areas of the body where there are defects during the operation of the turbine steam distribution system. The difference between the results of both methods in relation to their average value is ~20%.