By analyzing the measured corrugation data, the cause of rail corrugation was discussed theoretically. Then, the vehicle-track coupling model was used to study the stick-slip characteristics of wheel-rail system. Finally, the cause of rail corrugation was explained by combining modal analysis and wheel-rail stick-slip relation. The transverse stick-slip curve on the inner rail-inner wheel of the leading wheelset presents a negative slope characteristic, which makes the inner wheel easy to slide on the inner rail surface and aggravates the wear of inner rail; there are also negative slope sections of the stick-slip curve on the outer rail-outer wheel of the trailing wheelset, but the adhesion coefficient is relatively large, indicating that the outer wheel will not slide obviously and the wear is relatively small. Meantime, with the increase of line curve radius, the negative slope phenomenon of stick-slip curves on the inner and outer rail sides shows a decreasing trend, which illustrates that the sliding wear of wheel is gradually reduced, and thus the occurrence probability of rail corrugation decreases. Combined with modal analysis, it can be seen that the coupling action of wheel discs bending vibration and inner rail bending-torsional vibration is the main cause of rail corrugation under the condition of wheel-rail system with stick-slip negative slope.
{"title":"Cause Analysis of Rail Corrugation Based on Stick-slip Characteristics","authors":"Zhiqiang Wang, Z. Lei","doi":"10.3311/ppme.21159","DOIUrl":"https://doi.org/10.3311/ppme.21159","url":null,"abstract":"By analyzing the measured corrugation data, the cause of rail corrugation was discussed theoretically. Then, the vehicle-track coupling model was used to study the stick-slip characteristics of wheel-rail system. Finally, the cause of rail corrugation was explained by combining modal analysis and wheel-rail stick-slip relation. The transverse stick-slip curve on the inner rail-inner wheel of the leading wheelset presents a negative slope characteristic, which makes the inner wheel easy to slide on the inner rail surface and aggravates the wear of inner rail; there are also negative slope sections of the stick-slip curve on the outer rail-outer wheel of the trailing wheelset, but the adhesion coefficient is relatively large, indicating that the outer wheel will not slide obviously and the wear is relatively small. Meantime, with the increase of line curve radius, the negative slope phenomenon of stick-slip curves on the inner and outer rail sides shows a decreasing trend, which illustrates that the sliding wear of wheel is gradually reduced, and thus the occurrence probability of rail corrugation decreases. Combined with modal analysis, it can be seen that the coupling action of wheel discs bending vibration and inner rail bending-torsional vibration is the main cause of rail corrugation under the condition of wheel-rail system with stick-slip negative slope.","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90869941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mahmoud Kaffash Mirzarahimi, H. Khodarahmi, M. Ziashamami, R. Hosseini
Reducing the effects of unwanted shocks and waves is a very common problem in engineering. Some materials, due to their inherent properties, can be used as energy absorbers, such as foams, porous materials, and granular materials. porous granular materials that were considered in this study due to their low density and energy absorption capacity. But to use the granular material as the core of the sandwich panel, you have to think of a way to hold the granules together. In this article, using molding with resin, aluminum and polyurethane foam, an attempt has been made to make cores for sandwich panels from mineral pumice. the use of foam showed better performance than the other two materials. These adsorbents have the property of substrate flexibility and impact absorption and low density of porous materials at the same time. The properties of the core were obtained using a pressure test and used in software. Explosion experiments are free and Abaqus software is used in the simulation. The results show that the panel with a thicker back cover has a better performance in absorbing explosion energy. Increasing the thickness of the core has also increased energy absorption.
{"title":"Numerical and Experimental Study of the Use of Mineral Pumice in the Core of the Sandwich Panel to Absorb the Shock Wave","authors":"Mahmoud Kaffash Mirzarahimi, H. Khodarahmi, M. Ziashamami, R. Hosseini","doi":"10.3311/ppme.19341","DOIUrl":"https://doi.org/10.3311/ppme.19341","url":null,"abstract":"Reducing the effects of unwanted shocks and waves is a very common problem in engineering. Some materials, due to their inherent properties, can be used as energy absorbers, such as foams, porous materials, and granular materials. porous granular materials that were considered in this study due to their low density and energy absorption capacity. But to use the granular material as the core of the sandwich panel, you have to think of a way to hold the granules together. In this article, using molding with resin, aluminum and polyurethane foam, an attempt has been made to make cores for sandwich panels from mineral pumice. the use of foam showed better performance than the other two materials. These adsorbents have the property of substrate flexibility and impact absorption and low density of porous materials at the same time. The properties of the core were obtained using a pressure test and used in software. Explosion experiments are free and Abaqus software is used in the simulation. The results show that the panel with a thicker back cover has a better performance in absorbing explosion energy. Increasing the thickness of the core has also increased energy absorption.","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":"19 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88539590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Benkhettou, A. Sahli, S. Benbarek, Ismail Boudjemaa
Body pressure dispersion mattresses are useful tools for preventing pressure ulcers in patients with limited mobility who experience prolonged body weight-related compression loads at their body contact areas over time. The objective of this study is to propose and optimize a multicell finite element (FE) model of foam mattress to prevent patients from developing pressure ulcers (bed sores), by improving the contact pressure distribution on the upper mattress surface and immersion in the mattress. The NSGA-II multi-objective genetic algorithm was used to predict different configurations of cell materials to provide a more comfortable sleep. Our mattress model contains many cells (50 × 50 × 50), each of which can contain one of the nine different foam firmnesses. The NSGA-II algorithm attempts to combine the properties of soft and firm foams into a single mattress. however, the complexity and intersection of the fitness function objectives and the high number of possible chances forced the optimal solutions set to extend into the area under the result of foams that have a compressive strength between soft and firm. Based on the overall optimization results, the standard deviation ranged from 0.00325 to 0.00175 MPa and the maximum mattress immersion ranged from 50 mm to less than 20 mm. Mattresses with optimal configurations disperse body pressure smoothly to fit the patient's body shape.
{"title":"Multi-objective Optimization of Multi-cells Foam Mattress","authors":"A. Benkhettou, A. Sahli, S. Benbarek, Ismail Boudjemaa","doi":"10.3311/ppme.20259","DOIUrl":"https://doi.org/10.3311/ppme.20259","url":null,"abstract":"Body pressure dispersion mattresses are useful tools for preventing pressure ulcers in patients with limited mobility who experience prolonged body weight-related compression loads at their body contact areas over time. The objective of this study is to propose and optimize a multicell finite element (FE) model of foam mattress to prevent patients from developing pressure ulcers (bed sores), by improving the contact pressure distribution on the upper mattress surface and immersion in the mattress. The NSGA-II multi-objective genetic algorithm was used to predict different configurations of cell materials to provide a more comfortable sleep. Our mattress model contains many cells (50 × 50 × 50), each of which can contain one of the nine different foam firmnesses. The NSGA-II algorithm attempts to combine the properties of soft and firm foams into a single mattress. however, the complexity and intersection of the fitness function objectives and the high number of possible chances forced the optimal solutions set to extend into the area under the result of foams that have a compressive strength between soft and firm. Based on the overall optimization results, the standard deviation ranged from 0.00325 to 0.00175 MPa and the maximum mattress immersion ranged from 50 mm to less than 20 mm. Mattresses with optimal configurations disperse body pressure smoothly to fit the patient's body shape.","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":"67 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74259697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nowadays, Industry 4.0 and the Smart Manufacturing environment are increasingly taking advantage of Artificial Intelligence. There are more and more sensors, cameras, vision systems and barcodes in the production area, as a result of which the volume of data recorded during manufacturing and assembly operations is growing extremely fast. The interpretation and processing of such production-type data by humans is no longer possible effectively. In the Big Data domain, machine learning is playing an increasingly important role within data mining. This paper focuses on the product change processes of semi-automatic assembly line batch production and examines the impact of product type changes on the Overall Equipment Effectiveness (OEE) and attempts to determine future values through supervised machine learning. Using decision tree technology, the effect on the OEE value can be predicted with an accuracy of up to 1%. The presented data and conclusions come from a real industrial environment, so the obtained results are proven in practice.
{"title":"Predicting the Impact of Product Type Changes on Overall Equipment Effectiveness Through Machine Learning","authors":"Péter Dobra, J. Jósvai","doi":"10.3311/ppme.21320","DOIUrl":"https://doi.org/10.3311/ppme.21320","url":null,"abstract":"Nowadays, Industry 4.0 and the Smart Manufacturing environment are increasingly taking advantage of Artificial Intelligence. There are more and more sensors, cameras, vision systems and barcodes in the production area, as a result of which the volume of data recorded during manufacturing and assembly operations is growing extremely fast. The interpretation and processing of such production-type data by humans is no longer possible effectively. In the Big Data domain, machine learning is playing an increasingly important role within data mining. This paper focuses on the product change processes of semi-automatic assembly line batch production and examines the impact of product type changes on the Overall Equipment Effectiveness (OEE) and attempts to determine future values through supervised machine learning. Using decision tree technology, the effect on the OEE value can be predicted with an accuracy of up to 1%. The presented data and conclusions come from a real industrial environment, so the obtained results are proven in practice.","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":"112 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79615709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Younes Belbellaa, N. Kribes, M. Yallese, Habiba Lekmine, S. Boutabba, A. Bezazi
Titanium alloys are used in aeronautics and the shipbuilding industry for their good intrinsic properties, namely low density (40% less than steel), very good mechanical properties and resistance to corrosion. The purpose of this study is to optimize the cutting conditions during the turning of Ti-6Al-4V titanium alloy with Minimum of Quantity of Lubrication (MQL) conditions leading to minimize the surface roughness (Ra). The tests were carried out according to a Taguchi L18 design plan by varying four input factors namely: the cutting speed, the feed rate, the depth of cut and the cutting tool material (coated carbide with (PVD) (GC1125) and uncoated carbide (H13A)). Analysis of variance (ANOVA) was used to found the contribution of each factor and to determine which parameters had a significant influence on the surface roughness. The treatment of the results made it possible to propose a mathematical model, which allows predicting Ra. In addition, Taguchi Signal/Noise (S/N) analysis was used in order to optimize the cutting conditions permitting to minimize Ra. The Desirability Function (DF) was also determined. In addition, the obtained results were compared to the one determined using Response Surface Methodology (RSM) and Teaching and Learning Based Optimization (TLBO). It is important to note that the TLBO method gave a very satisfactory result.
{"title":"Comparative Study to Optimize Surface Roughness of the Titanium Alloy Ti-6Al-4V by Applying Taguchi, RSM and TLBO Methods","authors":"Younes Belbellaa, N. Kribes, M. Yallese, Habiba Lekmine, S. Boutabba, A. Bezazi","doi":"10.3311/ppme.17911","DOIUrl":"https://doi.org/10.3311/ppme.17911","url":null,"abstract":"Titanium alloys are used in aeronautics and the shipbuilding industry for their good intrinsic properties, namely low density (40% less than steel), very good mechanical properties and resistance to corrosion. The purpose of this study is to optimize the cutting conditions during the turning of Ti-6Al-4V titanium alloy with Minimum of Quantity of Lubrication (MQL) conditions leading to minimize the surface roughness (Ra). The tests were carried out according to a Taguchi L18 design plan by varying four input factors namely: the cutting speed, the feed rate, the depth of cut and the cutting tool material (coated carbide with (PVD) (GC1125) and uncoated carbide (H13A)). Analysis of variance (ANOVA) was used to found the contribution of each factor and to determine which parameters had a significant influence on the surface roughness. The treatment of the results made it possible to propose a mathematical model, which allows predicting Ra. In addition, Taguchi Signal/Noise (S/N) analysis was used in order to optimize the cutting conditions permitting to minimize Ra. The Desirability Function (DF) was also determined. In addition, the obtained results were compared to the one determined using Response Surface Methodology (RSM) and Teaching and Learning Based Optimization (TLBO). It is important to note that the TLBO method gave a very satisfactory result.","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":"5 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82891340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Selective laser melting (SLM) is a frequently used additive manufacturing technology for creating metallic, especially Ti6Al4V parts. After the production by SLM usually postprocessing is necessary for several reasons. Here the sliding friction diamond burnishing is applied as postprocessing procedure.In this paper an experimental study of surface hardness improvement of selective laser melted Ti6Al4V ELI cylindrical parts is demonstrated. The surface is modified by sliding friction diamond burnishing as postprocessing machining. The design of experiment method was applied to investigate effect of five factors (two SLM and three machining parameters) on surface hardness modification.It is shown that both SLM and postprocessing factors makes significant effect to the surface hardness improvement, most important ones are laser power, laser scan speed during manufacturing, and the burnishing force as factor of postprocessing. Empirical formulas are fit to measurement data, and visualized by surface plots. Relationship between factors and the surface hardness improvement is strongly nonlinear. In the investigated parameter window burnishing force has always positive effect to surface hardness improvement.Electron microscopic investigations show that change in surface hardness can be related to four main morphological changes: compression of the surface by plastic deformation of protrusions, attenuation of valleys, formation of inner cavities and creation of small protrusions by diamond tool. This paper is an extended paper of a conference paper published in the proceedings book of the XXXI. International Welding Conference (Kecskemét, Hungary).
{"title":"Surface Hardness Modification of Selective Laser Melted Ti6Al4V Parts by Sliding Friction Diamond Burnishing","authors":"G. Dezső, F. Szigeti, G. Varga","doi":"10.3311/ppme.21124","DOIUrl":"https://doi.org/10.3311/ppme.21124","url":null,"abstract":"Selective laser melting (SLM) is a frequently used additive manufacturing technology for creating metallic, especially Ti6Al4V parts. After the production by SLM usually postprocessing is necessary for several reasons. Here the sliding friction diamond burnishing is applied as postprocessing procedure.In this paper an experimental study of surface hardness improvement of selective laser melted Ti6Al4V ELI cylindrical parts is demonstrated. The surface is modified by sliding friction diamond burnishing as postprocessing machining. The design of experiment method was applied to investigate effect of five factors (two SLM and three machining parameters) on surface hardness modification.It is shown that both SLM and postprocessing factors makes significant effect to the surface hardness improvement, most important ones are laser power, laser scan speed during manufacturing, and the burnishing force as factor of postprocessing. Empirical formulas are fit to measurement data, and visualized by surface plots. Relationship between factors and the surface hardness improvement is strongly nonlinear. In the investigated parameter window burnishing force has always positive effect to surface hardness improvement.Electron microscopic investigations show that change in surface hardness can be related to four main morphological changes: compression of the surface by plastic deformation of protrusions, attenuation of valleys, formation of inner cavities and creation of small protrusions by diamond tool. This paper is an extended paper of a conference paper published in the proceedings book of the XXXI. International Welding Conference (Kecskemét, Hungary).","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":"36 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88556417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Due to the growing pace of urbanization and the rapid expansion of the population, the utilities nowadays are facing a more challenging task than ever before, to maintain the functionality of their massive Water Distribution Networks. In this paper, three different techniques are presented for the maximization of network robustness against random pipe-bursts. This paper analyses the vulnerability of segments of WDNs from the viewpoint of the consumers that is the product of the failure rate and the relative demand loss. Topological parameters could approximate the vulnerability. During the investigation, 27 real-life WDNs were analyzed from the region of Western Hungary. In two networks, a complete isolation valve replacement optimization is presented using these low-cost topological parameters as fitness functions. It is proved that by rearranging the isolation valves of the WDN, using a standard genetic algorithm and a fast-evaluated fitness function, the nature of the vulnerability distribution can be changed to a more favorable one. This means that it is possible to increase the robustness of a WDN even without using a calibrated hydraulic model; since these topological parameters can be extracted from simple databases.
{"title":"Isolation Valve Placement Optimization of Water Distribution Networks to Reduce Vulnerability","authors":"Richárd Wéber, Tamás Huzsvár, C.-S. Hős","doi":"10.3311/ppme.20694","DOIUrl":"https://doi.org/10.3311/ppme.20694","url":null,"abstract":"Due to the growing pace of urbanization and the rapid expansion of the population, the utilities nowadays are facing a more challenging task than ever before, to maintain the functionality of their massive Water Distribution Networks. In this paper, three different techniques are presented for the maximization of network robustness against random pipe-bursts. This paper analyses the vulnerability of segments of WDNs from the viewpoint of the consumers that is the product of the failure rate and the relative demand loss. Topological parameters could approximate the vulnerability. During the investigation, 27 real-life WDNs were analyzed from the region of Western Hungary. In two networks, a complete isolation valve replacement optimization is presented using these low-cost topological parameters as fitness functions. It is proved that by rearranging the isolation valves of the WDN, using a standard genetic algorithm and a fast-evaluated fitness function, the nature of the vulnerability distribution can be changed to a more favorable one. This means that it is possible to increase the robustness of a WDN even without using a calibrated hydraulic model; since these topological parameters can be extracted from simple databases.","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80378188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Adhesive lap joints are widely used in modern structures. Known analytical mathematical models of the stress state of lap joints describe the joints of straight beams or cylindrical coaxial pipes. It is assumed that the stress state of these structures depends on only one coordinate. The study of the stress state of plates with defects, which are reinforced by patches, in most cases requires the use of at least two-dimensional mathematical models. In this work, it is shown that the axial symmetry of the plate, the cut-out, the patch, and the applied load makes it possible to reduce the problem to a one-dimensional problem in the polar coordinate system. An adhesive lap joint with circular symmetry is considered for the first time. The stress-strain state of the structure is described in an analytical form. Comparison of the results of calculating the stress state of the joint with the results of finite element modelling showed good adequacy of the proposed mathematical model.
{"title":"Axisymmetric Stress State of Adhesive Joint of a Circular Patch with a Plate Weakened by a Circular Cut-out","authors":"S. Kurennov, N. Smetankina, K. Barakhov","doi":"10.3311/ppme.18801","DOIUrl":"https://doi.org/10.3311/ppme.18801","url":null,"abstract":"Adhesive lap joints are widely used in modern structures. Known analytical mathematical models of the stress state of lap joints describe the joints of straight beams or cylindrical coaxial pipes. It is assumed that the stress state of these structures depends on only one coordinate. The study of the stress state of plates with defects, which are reinforced by patches, in most cases requires the use of at least two-dimensional mathematical models. In this work, it is shown that the axial symmetry of the plate, the cut-out, the patch, and the applied load makes it possible to reduce the problem to a one-dimensional problem in the polar coordinate system. An adhesive lap joint with circular symmetry is considered for the first time. The stress-strain state of the structure is described in an analytical form. Comparison of the results of calculating the stress state of the joint with the results of finite element modelling showed good adequacy of the proposed mathematical model.","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":"105 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80473768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cooling circuits can be improved by using a desuperheater. A series connected desuperheater increases the efficiency of the circuit and allows the waste heat to be used, e.g., for DHW preparation. The study investigates the behavior of a parallel connected desuperheater for DHW preparation in an experimental cooling circuit. The basic parameters of the cooling circuit (efficiency, pressure, temperature and energy consumption) were evaluated when operating 1. with only a condenser and 2. with a condenser and a desuperheater connected in parallel. The results of the study show that a parallel connected condenser and desuperheater reduces the overall efficiency of the cooling circuit.
{"title":"Efficiency of Parallel Connected Desuperheater in a Cooling Circuit","authors":"M. Formánek, P. Horák","doi":"10.3311/ppme.20262","DOIUrl":"https://doi.org/10.3311/ppme.20262","url":null,"abstract":"Cooling circuits can be improved by using a desuperheater. A series connected desuperheater increases the efficiency of the circuit and allows the waste heat to be used, e.g., for DHW preparation. The study investigates the behavior of a parallel connected desuperheater for DHW preparation in an experimental cooling circuit. The basic parameters of the cooling circuit (efficiency, pressure, temperature and energy consumption) were evaluated when operating 1. with only a condenser and 2. with a condenser and a desuperheater connected in parallel. The results of the study show that a parallel connected condenser and desuperheater reduces the overall efficiency of the cooling circuit.","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":"70 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76214172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Friction stir welding (FSW) is a solid-state welding approach that can produce high quality joints in a fast and reliable manner. The present study is focused on optimization of multi-responses for micro-friction stir welded Al6061-T6 and SS304 sheets. Weld-parameters such as tool-rotational speed (TRS) and tool-traverse speed (TTS) influenced the mechanical responses of dissimilar welded joints significantly. In order to determine the effect of optimum process parameters on mechanical responses such as ultimate-tensile strength (UTS), micro-hardness (MHV) and surface-roughness (Ra) of dissimilar welded joints, an attempt has been made to find out the best possible set of process variables through multi-attribute optimization using technique for order of preference by similarity to ideal solution (TOPSIS) approach. Finally, the optimal solution shows that multi-responses of micro-friction stir welds can be improved through TOPSIS approach.
{"title":"Multi-attribute Optimization of Weld Parameters for Micro-friction Stir Welded Al6061/SS304 Sheets Using TOPSIS Approach","authors":"M. S. Srujan Manohar, Karunanithi Mahadevan","doi":"10.3311/ppme.17766","DOIUrl":"https://doi.org/10.3311/ppme.17766","url":null,"abstract":"Friction stir welding (FSW) is a solid-state welding approach that can produce high quality joints in a fast and reliable manner. The present study is focused on optimization of multi-responses for micro-friction stir welded Al6061-T6 and SS304 sheets. Weld-parameters such as tool-rotational speed (TRS) and tool-traverse speed (TTS) influenced the mechanical responses of dissimilar welded joints significantly. In order to determine the effect of optimum process parameters on mechanical responses such as ultimate-tensile strength (UTS), micro-hardness (MHV) and surface-roughness (Ra) of dissimilar welded joints, an attempt has been made to find out the best possible set of process variables through multi-attribute optimization using technique for order of preference by similarity to ideal solution (TOPSIS) approach. Finally, the optimal solution shows that multi-responses of micro-friction stir welds can be improved through TOPSIS approach.","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":"24 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89595511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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