Sliding Sector Control (SSC) design method for nonlinear systems is proposed in such a way that the system trajectories are kept around a nonlinear sliding surface which is surrounded by a nonlinear sliding sector. The SSC for the nonlinear system is derived so that the system trajectories are enforced to stay inside the sliding sector for tracking requirements. State-Dependent Differential Riccati Equations (SDDRE) are solved to design the nonlinear sliding surface for the nonlinear dynamical system. Within this context, SSC having nonlinear(or state-dependent) sliding surfaces are used to have a viable solution for the problem formulation. The evolving solutions of the Differential Riccati Equations are used to create the sliding surface which is kept inside the designed sliding sector so that the stability of the nonlinear system is ensured. The proposed SSC method is experimentally tested by applying it to an inner axis of a two axes gimbal system.
{"title":"Nonlinear State Dependent Sliding Sector Control of Gimbal Systems","authors":"B. E. Birinci, Özkan Özkan, M. U. Salamci","doi":"10.5755/j02.mech.31210","DOIUrl":"https://doi.org/10.5755/j02.mech.31210","url":null,"abstract":"Sliding Sector Control (SSC) design method for nonlinear systems is proposed in such a way that the system trajectories are kept around a nonlinear sliding surface which is surrounded by a nonlinear sliding sector. The SSC for the nonlinear system is derived so that the system trajectories are enforced to stay inside the sliding sector for tracking requirements. State-Dependent Differential Riccati Equations (SDDRE) are solved to design the nonlinear sliding surface for the nonlinear dynamical system. Within this context, SSC having nonlinear(or state-dependent) sliding surfaces are used to have a viable solution for the problem formulation. The evolving solutions of the Differential Riccati Equations are used to create the sliding surface which is kept inside the designed sliding sector so that the stability of the nonlinear system is ensured. The proposed SSC method is experimentally tested by applying it to an inner axis of a two axes gimbal system.","PeriodicalId":54741,"journal":{"name":"Mechanika","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45850421","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}
Z. Staliulionis, G. Miliauskas, S. Mohanty, J. Hattel
The electronics is protected using plastic or metallic enclosures. Although, the electronics is protected by the enclosures from the surrounding environment, the moisture can still enter the enclosure via gasket, plastic enclosure walls, cable feedthroughs. The moisture existing inside enclosure may condense on PCBA or components due to a temperature changes or different temperature levels and can lead to a moisture-related failures. The temperature in the enclosure is also very dependent on the location and the heating of electronic components. Furthermore, the electronics can be mounted nearby to other heating or cooling components in the complex mechanical systems, such as water pump or water meter. The paper concerns the complex transient heat and mass transfer processes between two connected enclosures with one being warm and another cold. The objective of the paper is to develop an in-house code based on the RC approach for predicting and studying the temperature and moisture behaviour inside two connected enclosures. The developed RC model combines one-dimensional description and lumped analysis for heat and mass transport. The modelling of temperature and moisture response is carried out under non-isothermal B3 STANAG ambient conditions. Moreover, the effect of different material of warm enclosure and the heating are considered.
{"title":"Numerical Modelling of Moisture Transport Between Two Enclosures Connected by a Tube","authors":"Z. Staliulionis, G. Miliauskas, S. Mohanty, J. Hattel","doi":"10.5755/j02.mech.32166","DOIUrl":"https://doi.org/10.5755/j02.mech.32166","url":null,"abstract":"The electronics is protected using plastic or metallic enclosures. Although, the electronics is protected by the enclosures from the surrounding environment, the moisture can still enter the enclosure via gasket, plastic enclosure walls, cable feedthroughs. The moisture existing inside enclosure may condense on PCBA or components due to a temperature changes or different temperature levels and can lead to a moisture-related failures. The temperature in the enclosure is also very dependent on the location and the heating of electronic components. Furthermore, the electronics can be mounted nearby to other heating or cooling components in the complex mechanical systems, such as water pump or water meter. The paper concerns the complex transient heat and mass transfer processes between two connected enclosures with one being warm and another cold. The objective of the paper is to develop an in-house code based on the RC approach for predicting and studying the temperature and moisture behaviour inside two connected enclosures. The developed RC model combines one-dimensional description and lumped analysis for heat and mass transport. The modelling of temperature and moisture response is carried out under non-isothermal B3 STANAG ambient conditions. Moreover, the effect of different material of warm enclosure and the heating are considered.","PeriodicalId":54741,"journal":{"name":"Mechanika","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45372166","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}
Athijayamani Athijayamani, P. Muthusamy, Sidhardhan Susaiyappan
In the present experimental study the effects of addition of Glass Fibers (GFs) and Silicon Carbide (SiC) particles on the mechanical and machinability behaviors of Areca Fine Fiber (AFF)-reinforced Phenol Formaldehyde (PF) composites were evaluated in three stages. Composites were prepared by hand lay-up technique at room temperature. From the first stage, it is observed that the 20AFF/20GF/PF hybrid composites give better mechanical properties than the other hybrid composites followed by the 10AFF/30GF/PF hybrid composite. The results of second stage revealed that the AFF/GF/SiC/PF hybrid composites exhibited the highest values of mechanical properties after addition of the 6% of SiC particles. From third stage, it is observed that the cutting speed is most significant process parameter during drilling of the 20AFF/20GF/6SiC/PF hybrid composite, followed by feed rate.
{"title":"Effects of Addition of Glass Fibers and SiC Particles on the Mechanical and Machinability Behaviours of Areca Fine Fiber-Reinforced Phenol Formaldehyde Composite","authors":"Athijayamani Athijayamani, P. Muthusamy, Sidhardhan Susaiyappan","doi":"10.5755/j02.mech.25443","DOIUrl":"https://doi.org/10.5755/j02.mech.25443","url":null,"abstract":"In the present experimental study the effects of addition of Glass Fibers (GFs) and Silicon Carbide (SiC) particles on the mechanical and machinability behaviors of Areca Fine Fiber (AFF)-reinforced Phenol Formaldehyde (PF) composites were evaluated in three stages. Composites were prepared by hand lay-up technique at room temperature. From the first stage, it is observed that the 20AFF/20GF/PF hybrid composites give better mechanical properties than the other hybrid composites followed by the 10AFF/30GF/PF hybrid composite. The results of second stage revealed that the AFF/GF/SiC/PF hybrid composites exhibited the highest values of mechanical properties after addition of the 6% of SiC particles. From third stage, it is observed that the cutting speed is most significant process parameter during drilling of the 20AFF/20GF/6SiC/PF hybrid composite, followed by feed rate.","PeriodicalId":54741,"journal":{"name":"Mechanika","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42559822","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}
Brakes are one of the most important systems in each vehicle. For this reason, numerous studies are carried out in many scientific institutions that allow for better understanding of friction and wear phenomenon. Therefore, the correctness of the obtained results is of great importance. Hence, the choice of the research method is not without significance. In this paper, it was decided to check how the choice of the method will affect the quality of the obtained results. The chosen methods were Ball-cratering and Pin-on-disc. Six groups of samples taken from three different types of pads were tested. The pads were both brand new and used. The analysis of the results was performed using the chi-square concordance test. It was established that at the significance level of 0.95, the choice of the research method was not statistically significant. Both methods provide similar high-quality results.
{"title":"Research on Tribological Features of Brake Friction Materials - Com-parison of the Results Obtained with the Pin-On-Disc and Ball-Cratering Methods","authors":"A. Borawski, D. Szpica, G. Mieczkowski","doi":"10.5755/j02.mech.31673","DOIUrl":"https://doi.org/10.5755/j02.mech.31673","url":null,"abstract":"Brakes are one of the most important systems in each vehicle. For this reason, numerous studies are carried out in many scientific institutions that allow for better understanding of friction and wear phenomenon. Therefore, the correctness of the obtained results is of great importance. Hence, the choice of the research method is not without significance. In this paper, it was decided to check how the choice of the method will affect the quality of the obtained results. The chosen methods were Ball-cratering and Pin-on-disc. Six groups of samples taken from three different types of pads were tested. The pads were both brand new and used. The analysis of the results was performed using the chi-square concordance test. It was established that at the significance level of 0.95, the choice of the research method was not statistically significant. Both methods provide similar high-quality results.","PeriodicalId":54741,"journal":{"name":"Mechanika","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48704922","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}
Rock bursts are a frequent occurrence in deep coal mining, and reducing the risk of rock bursts is necessary for the safe and efficient mining of coal. As honeycomb structures have good impact resistance, the design suggests that a honeycomb structure is adopted in the roof. A mechanical model of the hydraulic support is established, and the influence of geometric parameters on the impact resistance of the honeycomb structure is studied. Finally, the orthogonal test method was used to analyze the influence and weight of the geometric parameters on the anti-impact performance of the honeycomb structure with hydraulic leg stress and roof displacement as the evaluation indexes. This paper provides a new design idea for the research and development of an impact resistance hydraulic support in the underground coal mine, which is significant in ensuring coal mine safety.
{"title":"Optimization of Anti-Impact Energy Absorption Structure of Hydraulic Support","authors":"Qiang Zhang, Bao-Gui Li, Runxin Zhang","doi":"10.5755/j02.mech.32032","DOIUrl":"https://doi.org/10.5755/j02.mech.32032","url":null,"abstract":"Rock bursts are a frequent occurrence in deep coal mining, and reducing the risk of rock bursts is necessary for the safe and efficient mining of coal. As honeycomb structures have good impact resistance, the design suggests that a honeycomb structure is adopted in the roof. A mechanical model of the hydraulic support is established, and the influence of geometric parameters on the impact resistance of the honeycomb structure is studied. Finally, the orthogonal test method was used to analyze the influence and weight of the geometric parameters on the anti-impact performance of the honeycomb structure with hydraulic leg stress and roof displacement as the evaluation indexes. This paper provides a new design idea for the research and development of an impact resistance hydraulic support in the underground coal mine, which is significant in ensuring coal mine safety.","PeriodicalId":54741,"journal":{"name":"Mechanika","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46415610","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}
Based on the similarity principle, the basic parameters of the reduced-scale Krauss tester were derived from the full-scale Krauss tester by using the dimensional analysis method. The main structure of the Krauss testing machine had been made, and some components and parts such as brake system, servo loading system and torque measuring system had been designed and manufactured. The same batch and molded NAO brake friction material had been rigorously evaluated on two Krauss testers following ECE R-90 procedure as per the ‘‘Economic Commission for Europe” (ECE) regulations and these parameters such as friction torque, brake pressure, friction coefficient, test temperature and time had been discussed. The results showed that the reduced-scale Krauss tester was faster response than that of the full-scale Krauss tester in the process of brake growth and brake release, the brake completion time was about 370 ms ahead of schedule. However, the full-scale Krauss tester had a slower response and the brake completion time delay was about 240 ms. During the entire test, the average coefficient of friction was closer and the relative error is 6.3%, and the maximum and minimum values of the friction coefficient appeared at the same brake sequence, test section and brake cycle. The test temperature had good linear correlation in the whole test process. The total test time for reduced-scale Krauss tester was about 4/5 of full-scale Krauss tester. In each test, if the same other conditions existed, the power cost of the reduced-scale Krauss tester is 20.79 % of the power cost of the full-scale Krauss tester when the ECE R-90 test program was executed. From the comparison of the main test indexes, the test data of the scaled Krauss test machine reflected the fluctuation and correlation of the test data of the full-scale Krauss test machine to a certain extent, providing a new test equipment for the brake friction material.
{"title":"Development and Comparative Evaluation of Reduced-scale Krauss Friction Tester based on Similarity Theory","authors":"Zhenyu Wang, Jie Wang, Lining Wang, Yunhai Ma","doi":"10.5755/j02.mech.32030","DOIUrl":"https://doi.org/10.5755/j02.mech.32030","url":null,"abstract":"Based on the similarity principle, the basic parameters of the reduced-scale Krauss tester were derived from the full-scale Krauss tester by using the dimensional analysis method. The main structure of the Krauss testing machine had been made, and some components and parts such as brake system, servo loading system and torque measuring system had been designed and manufactured. The same batch and molded NAO brake friction material had been rigorously evaluated on two Krauss testers following ECE R-90 procedure as per the ‘‘Economic Commission for Europe” (ECE) regulations and these parameters such as friction torque, brake pressure, friction coefficient, test temperature and time had been discussed. The results showed that the reduced-scale Krauss tester was faster response than that of the full-scale Krauss tester in the process of brake growth and brake release, the brake completion time was about 370 ms ahead of schedule. However, the full-scale Krauss tester had a slower response and the brake completion time delay was about 240 ms. During the entire test, the average coefficient of friction was closer and the relative error is 6.3%, and the maximum and minimum values of the friction coefficient appeared at the same brake sequence, test section and brake cycle. The test temperature had good linear correlation in the whole test process. The total test time for reduced-scale Krauss tester was about 4/5 of full-scale Krauss tester. In each test, if the same other conditions existed, the power cost of the reduced-scale Krauss tester is 20.79 % of the power cost of the full-scale Krauss tester when the ECE R-90 test program was executed. From the comparison of the main test indexes, the test data of the scaled Krauss test machine reflected the fluctuation and correlation of the test data of the full-scale Krauss test machine to a certain extent, providing a new test equipment for the brake friction material.","PeriodicalId":54741,"journal":{"name":"Mechanika","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43517059","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}
Qingliang Zeng, Guangyu Zhou, Ji Shi, Yongqing Li, Yuanqiang Liu, Tianming Chen, Liang Wang
Workspace analysis is an indispensable part of robot research. The workspace volume is an important factor to measure the working ability of parallel robot. In order to maximize the workspace of parallel robot, this paper solves the workspace of robot by using Monte Carlo method, and obtains that the workspace volume is 2.142×106 mm3, which is optimized by the multi Island genetic algorithm in the global optimization algorithm. After optimization, the workspace volume increases to 8.25×106 mm3, the volume of workspace before and after optimization is increased by 3.85 times. The influence of various structural parameters of the parallel robot on the workspace volume is analyzed and studied. It is obtained that the rod length ratio of the connecting rod and the driving rod has the greatest influence on the workspace volume, followed by the ratio of the center angle of the long and short sides, and the radius of the moving platform has the least influence. Furthermore, the influence of single parameter on the workspace volume is analyzed. When other parameters remain unchanged, the maximum workspace volume can be achieved when the rod length ratio of connecting rod and driving rod is 1.25, or the ratio of center angle of long and short sides is 1.53.
{"title":"Robot Workspace Optimization based on Monte Carlo Method and Multi Island Genetic Algorithm","authors":"Qingliang Zeng, Guangyu Zhou, Ji Shi, Yongqing Li, Yuanqiang Liu, Tianming Chen, Liang Wang","doi":"10.5755/j02.mech.32035","DOIUrl":"https://doi.org/10.5755/j02.mech.32035","url":null,"abstract":"Workspace analysis is an indispensable part of robot research. The workspace volume is an important factor to measure the working ability of parallel robot. In order to maximize the workspace of parallel robot, this paper solves the workspace of robot by using Monte Carlo method, and obtains that the workspace volume is 2.142×106 mm3, which is optimized by the multi Island genetic algorithm in the global optimization algorithm. After optimization, the workspace volume increases to 8.25×106 mm3, the volume of workspace before and after optimization is increased by 3.85 times. The influence of various structural parameters of the parallel robot on the workspace volume is analyzed and studied. It is obtained that the rod length ratio of the connecting rod and the driving rod has the greatest influence on the workspace volume, followed by the ratio of the center angle of the long and short sides, and the radius of the moving platform has the least influence. Furthermore, the influence of single parameter on the workspace volume is analyzed. When other parameters remain unchanged, the maximum workspace volume can be achieved when the rod length ratio of connecting rod and driving rod is 1.25, or the ratio of center angle of long and short sides is 1.53.","PeriodicalId":54741,"journal":{"name":"Mechanika","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46837525","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 cavitation damage of the pollutant wall caused by shock wave and microjet in the process of bubble collapse has attracted widespread attention from scholars. However, many researches focus on bubble collapse from the macroscopic experimental point of view, the dynamics of which is still not clear. In this paper, it constructs bubbles with different radii, runs different models under different compressive strain rates, takes the pressure on the upper and lower walls of pollutants as the research target, and summarizes the influence of compressive strain rates, initial radius of bubbles and temperatures on the release pressure of bubble collapse on the pollutant wall. The results show that: as the initial radius of bubbles increase, the maximum pressure on the upper and lower walls of benzamide increases first and then decreases. The pressure release rate of bubble increases with the increase of the compressive strain rate. Based on the pressure on the upper and lower wall surfaces of the benzamide, the temperature and initial radius of the bubble have a large influence, and the influence of the compressive strain rate is small. Under the simulation conditions of the paper, when bubble collapse is used to release energy to treat pollutants, the recommended bubble radius is 10-15 Å. The paper not only reveals the influence of the initial radius of the bubble, the compressive strain rate and the temperature on the pressure released by the bubble collapse on the pollutant wall, but also provides theoretical guidance for the application of cavitation.
{"title":"Analysis of the Wall Force on the Bubble Collapse of the Benzamide Based on Molecular Dynamics Simulation","authors":"Wei Xu, Xiuli Wang, Jinhua Liu, Yuanyuan Zhao, Guohui Zhao, Wenzhuo Guo","doi":"10.5755/j02.mech.29875","DOIUrl":"https://doi.org/10.5755/j02.mech.29875","url":null,"abstract":"The cavitation damage of the pollutant wall caused by shock wave and microjet in the process of bubble collapse has attracted widespread attention from scholars. However, many researches focus on bubble collapse from the macroscopic experimental point of view, the dynamics of which is still not clear. In this paper, it constructs bubbles with different radii, runs different models under different compressive strain rates, takes the pressure on the upper and lower walls of pollutants as the research target, and summarizes the influence of compressive strain rates, initial radius of bubbles and temperatures on the release pressure of bubble collapse on the pollutant wall. The results show that: as the initial radius of bubbles increase, the maximum pressure on the upper and lower walls of benzamide increases first and then decreases. The pressure release rate of bubble increases with the increase of the compressive strain rate. Based on the pressure on the upper and lower wall surfaces of the benzamide, the temperature and initial radius of the bubble have a large influence, and the influence of the compressive strain rate is small. Under the simulation conditions of the paper, when bubble collapse is used to release energy to treat pollutants, the recommended bubble radius is 10-15 Å. The paper not only reveals the influence of the initial radius of the bubble, the compressive strain rate and the temperature on the pressure released by the bubble collapse on the pollutant wall, but also provides theoretical guidance for the application of cavitation.","PeriodicalId":54741,"journal":{"name":"Mechanika","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47497541","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}
A new plate element has been formulated by simply adding one degree of freedom for each node on the basis of the classical ACM element, based on a modified first-order shear deformation plate theory, which assumes that the plate deflection has bending and shearing components, with two rotations defined by differentiations of bending deflections. This new element, with 16 degrees of freedom, exhibits no locking effect, and is appropriate for both thin and thick plates. To assess the performance of the newly developed plate element, it has been applied to the prediction of natural frequencies and critical bucking loads of square plates with various thickness ratios and boundary conditions. Comparisons with available analytical and numerical solutions in open publication show that the new element leads to highly accurate solutions in free vibration and eigen-buckling analysis with good convergence, and can be competitive with existing plate elements.
{"title":"A New Shear Locking-Free Quadrilateral Plate Element for Free Vibra-tion and Eigen-Buckling Analysis","authors":"Wei XiaXIANGng, Z. Yao, Lina He","doi":"10.5755/j02.mech.30331","DOIUrl":"https://doi.org/10.5755/j02.mech.30331","url":null,"abstract":"A new plate element has been formulated by simply adding one degree of freedom for each node on the basis of the classical ACM element, based on a modified first-order shear deformation plate theory, which assumes that the plate deflection has bending and shearing components, with two rotations defined by differentiations of bending deflections. This new element, with 16 degrees of freedom, exhibits no locking effect, and is appropriate for both thin and thick plates. \u0000To assess the performance of the newly developed plate element, it has been applied to the prediction of natural frequencies and critical bucking loads of square plates with various thickness ratios and boundary conditions. Comparisons with available analytical and numerical solutions in open publication show that the new element leads to highly accurate solutions in free vibration and eigen-buckling analysis with good convergence, and can be competitive with existing plate elements.","PeriodicalId":54741,"journal":{"name":"Mechanika","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45737762","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}
Huanle Zhai, Wei Li, Leilei Ji, M. Awais, Jiwei Li, Shuo Li
A general design formula for rotor profile is proposed based on conjugation theory and feasibly verified by using the four different design shapes. The overset mesh method and the realizable k-ε two-layer turbulence model are used for simulation calculation. The results stated that the average volume flow error of hydrogen medium and air medium is small, so an alternative experimental study has been carried out. By building a test system for experimental verification, it is found that the error between the simulation results and the experimental results is small at the low-pressure ratio and increases at the high-pressure ratio because the influence of the ambient temperature is not considered. The results further verified the reliability using the simulation calculation method. At last, the fluid characteristics of the two-tangent-arcs type, single-arc type, ellipse type, and quadratic-curve type rotors are evaluated. The result shows that the comprehensive performance of the single-arc type rotor is superlative as followed by the ellipse type rotor. However, the quadratic-curve rotor has the largest average flow but the worst flow stability and the two-tangent-arcs rotor shows the smallest average flow.
{"title":"Profile Design and Performance Research of Hydrogen Circulation Pump in Fuel Cell System","authors":"Huanle Zhai, Wei Li, Leilei Ji, M. Awais, Jiwei Li, Shuo Li","doi":"10.5755/j02.mech.31528","DOIUrl":"https://doi.org/10.5755/j02.mech.31528","url":null,"abstract":"A general design formula for rotor profile is proposed based on conjugation theory and feasibly verified by using the four different design shapes. The overset mesh method and the realizable k-ε two-layer turbulence model are used for simulation calculation. The results stated that the average volume flow error of hydrogen medium and air medium is small, so an alternative experimental study has been carried out. By building a test system for experimental verification, it is found that the error between the simulation results and the experimental results is small at the low-pressure ratio and increases at the high-pressure ratio because the influence of the ambient temperature is not considered. The results further verified the reliability using the simulation calculation method. At last, the fluid characteristics of the two-tangent-arcs type, single-arc type, ellipse type, and quadratic-curve type rotors are evaluated. The result shows that the comprehensive performance of the single-arc type rotor is superlative as followed by the ellipse type rotor. However, the quadratic-curve rotor has the largest average flow but the worst flow stability and the two-tangent-arcs rotor shows the smallest average flow.","PeriodicalId":54741,"journal":{"name":"Mechanika","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44342326","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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