In a context of increased competition, companies are looking to optimize all the components of their systems. They use compression springs with constant pitch for their linear force/length relationship. However, it appears that the classic formula determining the global load-length of the spring is not always accurate enough. It does not consider the effects of the spring's ends, which can induce non-linear behaviour at the beginning of compression and thus propagate an error over the full load-length estimated. The paper investigates the entire behaviour of a cylindrical compression spring, not ground, using analytical, simulation and experimental approaches in order to help engineers design compression springs with greater accuracy. It is built with an analytical finite element method, considering all the geometry and force components of the spring. As a result, the global load-length of compression springs can be calculated with more accuracy. Moreover, it is now possible to determine the effective tri-linear load-length relation of compression springs not ground and thus to enlarge the operating range commonly defined by standards. This study is the first that enables the behaviour to be calculated quickly, by saving time on dimensioning optimisation and on the manufacturing process of compression springs not ground.
{"title":"Improved analytical model for cylindrical compression springs not ground considering end behavior of end coils","authors":"Guillaume Cadet, M. Paredes, Hervé Orcière","doi":"10.1051/meca/2021048","DOIUrl":"https://doi.org/10.1051/meca/2021048","url":null,"abstract":"In a context of increased competition, companies are looking to optimize all the components of their systems. They use compression springs with constant pitch for their linear force/length relationship. However, it appears that the classic formula determining the global load-length of the spring is not always accurate enough. It does not consider the effects of the spring's ends, which can induce non-linear behaviour at the beginning of compression and thus propagate an error over the full load-length estimated. The paper investigates the entire behaviour of a cylindrical compression spring, not ground, using analytical, simulation and experimental approaches in order to help engineers design compression springs with greater accuracy. It is built with an analytical finite element method, considering all the geometry and force components of the spring. As a result, the global load-length of compression springs can be calculated with more accuracy. Moreover, it is now possible to determine the effective tri-linear load-length relation of compression springs not ground and thus to enlarge the operating range commonly defined by standards. This study is the first that enables the behaviour to be calculated quickly, by saving time on dimensioning optimisation and on the manufacturing process of compression springs not ground.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"104 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87732656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Effects of various clearances of variable-pitch screw vacuum pump on gas backflow of internal flow field of the pump cavity is studied. The theoretical tooth surfaces of screw rotor are optimized by radial, normal equidistance modifications, and four types of stable clearances of rotor circumferential, radial, tooth shape and tooth sides are obtained. The backflow calculation model in clearances considering Couette backflow and orifice backflow is improved. The three-dimensional model of variable-pitch screw vacuum pump is designed, and the experimental prototype and test device are developed. The internal backflow of vacuum pump is analyzed by using the commercial software Ansys-Fluent® and the calculation model. The results show that the smaller the clearances, the smaller the backflow and the higher the vacuum degree. Among the four types of clearances, the circumferential clearance plays the primary roles. The backflow is directly proportional to the inlet pressure and rotating speed. Predictions are validated by the experimental data with satisfied agreement.
{"title":"Effects of stable clearances on backflow in the variable-pitch screw vacuum pump","authors":"Li Zhang, Yongju Zhang, Ziyun Chen","doi":"10.1051/meca/2021046","DOIUrl":"https://doi.org/10.1051/meca/2021046","url":null,"abstract":"Effects of various clearances of variable-pitch screw vacuum pump on gas backflow of internal flow field of the pump cavity is studied. The theoretical tooth surfaces of screw rotor are optimized by radial, normal equidistance modifications, and four types of stable clearances of rotor circumferential, radial, tooth shape and tooth sides are obtained. The backflow calculation model in clearances considering Couette backflow and orifice backflow is improved. The three-dimensional model of variable-pitch screw vacuum pump is designed, and the experimental prototype and test device are developed. The internal backflow of vacuum pump is analyzed by using the commercial software Ansys-Fluent® and the calculation model. The results show that the smaller the clearances, the smaller the backflow and the higher the vacuum degree. Among the four types of clearances, the circumferential clearance plays the primary roles. The backflow is directly proportional to the inlet pressure and rotating speed. Predictions are validated by the experimental data with satisfied agreement.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"16 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78313183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The presence of flexibilities in rotational joints can limit the kinematic performances of manipulators doing high speed tasks as Pick and Place. The problem addressed in this work concerns the vibration control of serial robots with flexible joints performing Pick and Place tasks in order to improve productivity. Based on a dynamic model of a robot with flexible joints, a model-based control law is proposed with its associated tuning methodology. The robot dynamic model is then the key point of our methodology. This dynamic model considers stiffness and damping of each flexible joint. To guarantee its accuracy, a geometrical and dynamic identification procedure is realized. The objective is to show the relevancy of the proposed approach which integrates joint flexibilities in the control law. Theoretical results based on a representative model are used to illustrate the benefit of this model-based control law compare to two other control strategies (Feedforward control and control dedicated to rigid structures). Finally, a sensitivity analysis of this control law is realized to quantify the impact of modelling error and conclude on the criticality of joint damping value on vibration decreasing.
{"title":"A model-based control law for vibration reduction of serial robots with flexible joints","authors":"Jacques Farah, H. Chanal, N. Bouton, V. Gagnol","doi":"10.1051/meca/2021036","DOIUrl":"https://doi.org/10.1051/meca/2021036","url":null,"abstract":"The presence of flexibilities in rotational joints can limit the kinematic performances of manipulators doing high speed tasks as Pick and Place. The problem addressed in this work concerns the vibration control of serial robots with flexible joints performing Pick and Place tasks in order to improve productivity. Based on a dynamic model of a robot with flexible joints, a model-based control law is proposed with its associated tuning methodology. The robot dynamic model is then the key point of our methodology. This dynamic model considers stiffness and damping of each flexible joint. To guarantee its accuracy, a geometrical and dynamic identification procedure is realized. The objective is to show the relevancy of the proposed approach which integrates joint flexibilities in the control law. Theoretical results based on a representative model are used to illustrate the benefit of this model-based control law compare to two other control strategies (Feedforward control and control dedicated to rigid structures). Finally, a sensitivity analysis of this control law is realized to quantify the impact of modelling error and conclude on the criticality of joint damping value on vibration decreasing.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"5 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79644815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Forming sheet metals under blast loading or the explosive forming technique has many advantages for productions, but it is restricted due to its accuracy. This paper introduces a novel theoretical-empirical study for explosive sheet metal forming based on the simple plasticity principles. It provides a method of producing the sheet metal cone parts forming under blast loading, including an analytical model and experimental validation. Firstly, a theoretical-empirical model for cone forming based on underwater explosion employing the impulse method is developed. The model on the whole revealed the relationships among the geometrical parameters of forming a process that is very useful to predict the certain explosive mass for complete forming a cone part. Afterward, a series of experiments are conducted to validate the developed model and also for the required modification in the solution. Comparing the theoretical-empirical solution and experimental results, the ability of the presented model for estimation of the explosive mass is demonstrated. Experimental results show that the theoretical model matched the experiments well.
{"title":"Physically-based modelling for sheet metal cone parts forming under blast loading","authors":"R. Alipour","doi":"10.1051/MECA/2021002","DOIUrl":"https://doi.org/10.1051/MECA/2021002","url":null,"abstract":"Forming sheet metals under blast loading or the explosive forming technique has many advantages for productions, but it is restricted due to its accuracy. This paper introduces a novel theoretical-empirical study for explosive sheet metal forming based on the simple plasticity principles. It provides a method of producing the sheet metal cone parts forming under blast loading, including an analytical model and experimental validation. Firstly, a theoretical-empirical model for cone forming based on underwater explosion employing the impulse method is developed. The model on the whole revealed the relationships among the geometrical parameters of forming a process that is very useful to predict the certain explosive mass for complete forming a cone part. Afterward, a series of experiments are conducted to validate the developed model and also for the required modification in the solution. Comparing the theoretical-empirical solution and experimental results, the ability of the presented model for estimation of the explosive mass is demonstrated. Experimental results show that the theoretical model matched the experiments well.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"14 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90928310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Due to the set of factors and conditions, the stream pressure through the orifice decreases, which can lead to the occurrence of the cavitation phenomenon. The most important factor in this regard is the geometry of orifice. In the first part of this study, the flow through two types of single-hole orifice and a multi-hole orifice were experimentally studied. The results showed that the single hole orifice with a two-sided sloped edge caused less pressure drop, which in order to control the cavitation phenomenon is more efficient compared to the single-hole and multi-hole orifices with one-sided sloped edges and the same equal diameter ratio. Additionally, all experiments were simulated in the second part of this research using finite volume methods. Considering the complexity of the problem, several numerical solutions were investigated to approach the experimental results. Finally, it was determined that the type of gridding, turbulence method, and cavitation model have a great influence on the accuracy of the obtained numerical results.
{"title":"Experimental and numerical investigation of geometric effect on cavitation flow through orifice","authors":"Mohammad Reza Davoudi, Miralam Mahdi","doi":"10.1051/MECA/2021018","DOIUrl":"https://doi.org/10.1051/MECA/2021018","url":null,"abstract":"Due to the set of factors and conditions, the stream pressure through the orifice decreases, which can lead to the occurrence of the cavitation phenomenon. The most important factor in this regard is the geometry of orifice. In the first part of this study, the flow through two types of single-hole orifice and a multi-hole orifice were experimentally studied. The results showed that the single hole orifice with a two-sided sloped edge caused less pressure drop, which in order to control the cavitation phenomenon is more efficient compared to the single-hole and multi-hole orifices with one-sided sloped edges and the same equal diameter ratio. Additionally, all experiments were simulated in the second part of this research using finite volume methods. Considering the complexity of the problem, several numerical solutions were investigated to approach the experimental results. Finally, it was determined that the type of gridding, turbulence method, and cavitation model have a great influence on the accuracy of the obtained numerical results.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"62 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90441313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chiller plants are the most energy consuming system during summer season in residential, commercial and hospital buildings. The highly variable cooling demand of the buildings connected to a hybrid chiller plant included absorption and vapor compression chillers to achieve higher energy efficiencies is one of the important issues. Cooling load sharing strategies and apply the variable water flow system in chiller plant have a significant impact on energy consumption and consequently with more productivity and environmentally protected. This paper examines the behavior and pattern of energy consumption in a hybrid chiller plant that includes a combination of two air-cooled screw vapor compression and three single effect absorption chillers. In order to properly understand the pattern of energy consumption, an existing mechanical room in a hospital in Tehran has been studied for five months, and its energy consumption has been compared with the optimized model. The results indicate that the sequence of the chiller function and the way in which they are placed in the circuit during a partial load, is in highest importance in view point of energy saving also by Applying of variable water flow system for optimized chiller loading the more energy saving is achieved for hybrid absorption and vapor compression chiller plant.
{"title":"Variable flow and optimization of chiller loading effect on energy saving for screw vapor compression-single effect absorption hybrid chiller plant in hospital mechanical room ‒ case study: Tehran heart hospital","authors":"R. Boghosian, M. Mafi, M. H. Panjeshahi, A. Ataei","doi":"10.1051/MECA/2021006","DOIUrl":"https://doi.org/10.1051/MECA/2021006","url":null,"abstract":"Chiller plants are the most energy consuming system during summer season in residential, commercial and hospital buildings. The highly variable cooling demand of the buildings connected to a hybrid chiller plant included absorption and vapor compression chillers to achieve higher energy efficiencies is one of the important issues. Cooling load sharing strategies and apply the variable water flow system in chiller plant have a significant impact on energy consumption and consequently with more productivity and environmentally protected. This paper examines the behavior and pattern of energy consumption in a hybrid chiller plant that includes a combination of two air-cooled screw vapor compression and three single effect absorption chillers. In order to properly understand the pattern of energy consumption, an existing mechanical room in a hospital in Tehran has been studied for five months, and its energy consumption has been compared with the optimized model. The results indicate that the sequence of the chiller function and the way in which they are placed in the circuit during a partial load, is in highest importance in view point of energy saving also by Applying of variable water flow system for optimized chiller loading the more energy saving is achieved for hybrid absorption and vapor compression chiller plant.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"84 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86572709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jun Li, H. Gurgenci, Jishun Li, Z. Guan, Lun Li, Y. Xue
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.
{"title":"Numerical investigation on the cooling performance of a novel jet cooler design for a supercritical CO2 turbine rotor shaft cooling","authors":"Jun Li, H. Gurgenci, Jishun Li, Z. Guan, Lun Li, Y. Xue","doi":"10.1051/meca/2021049","DOIUrl":"https://doi.org/10.1051/meca/2021049","url":null,"abstract":"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.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"47 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75739641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The finger skin contains a variety of receptors, which provide multiple tactile sensing channels. When a finger touches the surface of an object, people can simultaneously perceive curvature, texture, softness, temperature, and so on. However, in most of research activities, the designed haptic feedback devices can only focus on a certain channel. In this paper, the rendering of curved and periodic textured surfaces involving two channels, i.e., curvature and texture, was studied. Two psychophysical experiments were conducted to investigate whether the coupling of kinesthetic feedback of curvature and tactile feedback of texture could reproduce curved and textured surfaces with high fidelity. The results showed a deviation of the point of subjective equality values in terms of curvature and roughness, indicating that the curvature rendering and texture rendering have an impact on each other. Therefore, it is necessary to correct the bias when making virtual rendering. The influence of curvature on texture rendering is reduced by recalculating and adjusting the spatial period of the synthesized texture in real-time; the influence of texture on curvature rendering is eliminate by compensating the force difference between touch on physical strip and artificial stimulus.
{"title":"Combination of oriented-plane curvature reproduction and squeeze film effect-based texture reproduction to simulate curved and textured surface","authors":"Tao Zeng, Yan Liu, Enshan Ouyang","doi":"10.1051/MECA/2021024","DOIUrl":"https://doi.org/10.1051/MECA/2021024","url":null,"abstract":"The finger skin contains a variety of receptors, which provide multiple tactile sensing channels. When a finger touches the surface of an object, people can simultaneously perceive curvature, texture, softness, temperature, and so on. However, in most of research activities, the designed haptic feedback devices can only focus on a certain channel. In this paper, the rendering of curved and periodic textured surfaces involving two channels, i.e., curvature and texture, was studied. Two psychophysical experiments were conducted to investigate whether the coupling of kinesthetic feedback of curvature and tactile feedback of texture could reproduce curved and textured surfaces with high fidelity. The results showed a deviation of the point of subjective equality values in terms of curvature and roughness, indicating that the curvature rendering and texture rendering have an impact on each other. Therefore, it is necessary to correct the bias when making virtual rendering. The influence of curvature on texture rendering is reduced by recalculating and adjusting the spatial period of the synthesized texture in real-time; the influence of texture on curvature rendering is eliminate by compensating the force difference between touch on physical strip and artificial stimulus.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"30 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76039215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Frame saw machine is one of machine tools that is used to process dimension stone. The velocity fluctuation of traditional feed drive system (FDS) lead to excessive wear of diamond particles. The dynamic performance of the FDS has time-varying characteristics during the processing of stone with a large material removal rate. In this paper, a novel FDS was proposed. Firstly, the dynamic modeling of FDS was set up on account of lumped parameter method (LPM). Then the speed of the new FDS was compared with that of the traditional FDS. Finally, the frequency response characteristics of the system were solved by Lagrange and state space method. Results showed that the new FDS has a faster response feed and less velocity fluctuation. The natural frequency and the amplitude of acceleration increase with decreasing load. With the time-varying load, the range of the second-order natural frequency increased by 50 Hz, which was larger than that of the first-order. The modal test verified that the first two natural frequencies of the saw blade are within the range of the natural frequencies of FDS. The proposed FDS can guide for design, reduce the wear of diamond, and improve processing quality.
{"title":"Dynamics modeling and analysis of feed drive system for a frame saw machine considering time-varying load","authors":"Depeng Sun, Jinsheng Zhang","doi":"10.1051/MECA/2021019","DOIUrl":"https://doi.org/10.1051/MECA/2021019","url":null,"abstract":"Frame saw machine is one of machine tools that is used to process dimension stone. The velocity fluctuation of traditional feed drive system (FDS) lead to excessive wear of diamond particles. The dynamic performance of the FDS has time-varying characteristics during the processing of stone with a large material removal rate. In this paper, a novel FDS was proposed. Firstly, the dynamic modeling of FDS was set up on account of lumped parameter method (LPM). Then the speed of the new FDS was compared with that of the traditional FDS. Finally, the frequency response characteristics of the system were solved by Lagrange and state space method. Results showed that the new FDS has a faster response feed and less velocity fluctuation. The natural frequency and the amplitude of acceleration increase with decreasing load. With the time-varying load, the range of the second-order natural frequency increased by 50 Hz, which was larger than that of the first-order. The modal test verified that the first two natural frequencies of the saw blade are within the range of the natural frequencies of FDS. The proposed FDS can guide for design, reduce the wear of diamond, and improve processing quality.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"76 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77212806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Conventional mattresses can not adjust precisely according to the individualized spinal alignment. In addition, there is no theoretical basis for quantitative design and adjustment of mattresses firmness. The purpose of this paper is to overcome deficiency of traditional air chambers for research of ergonomic mattresses in accordance with spinal alignment. A novel variable stiffness air spring was designed and static experiments were conducted to analyze its mechanical properties and its influence factors. An analytical model based on geometric parameters and initial internal pressure was established. The results showed that the air spring has nonlinear stiffness during the working process. Furthermore, the model can predict the load of the air spring accurately at any equilibrium position with an average error of 6.96%. The initial stiffness, volume and assembly height could be predicted by means of geometric parameters and initial internal pressure. The conclusions are that the novel air spring can obtain predictable stiffness compared with cubic and the rod-shaped air chambers, which provides a theoretical basis and possible solution for the study of stiffness adaptive ergonomic mattress according to spinal alignment.
{"title":"Mechanical characteristic and analytical model of novel air spring for ergonomic mattress","authors":"Yao Chao, Libing Shen, Ming Liu","doi":"10.1051/MECA/2021035","DOIUrl":"https://doi.org/10.1051/MECA/2021035","url":null,"abstract":"Conventional mattresses can not adjust precisely according to the individualized spinal alignment. In addition, there is no theoretical basis for quantitative design and adjustment of mattresses firmness. The purpose of this paper is to overcome deficiency of traditional air chambers for research of ergonomic mattresses in accordance with spinal alignment. A novel variable stiffness air spring was designed and static experiments were conducted to analyze its mechanical properties and its influence factors. An analytical model based on geometric parameters and initial internal pressure was established. The results showed that the air spring has nonlinear stiffness during the working process. Furthermore, the model can predict the load of the air spring accurately at any equilibrium position with an average error of 6.96%. The initial stiffness, volume and assembly height could be predicted by means of geometric parameters and initial internal pressure. The conclusions are that the novel air spring can obtain predictable stiffness compared with cubic and the rod-shaped air chambers, which provides a theoretical basis and possible solution for the study of stiffness adaptive ergonomic mattress according to spinal alignment.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83114520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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