Pub Date : 2022-01-01DOI: 10.23977/jemm.2022.070105
F. Chen, Yujie Bai
To explore the characters of geothermal recovery process of deep borehole heat exchanger, a geothermal recovery process was simulated to explore the difference in stratum temperature distribution change under layered model and uniform model. The results indicated that the geothermal recovery rate is sharp at first and slow down then. The outlet temperature would be higher in the next heat extraction stage if the longer geothermal recovery period was adopted. Considering the time cost during the geothermal recovery period, the suggesting proportion of heat extraction and geothermal recovery could adopt 1:1. In addition, the uniform model cannot reveal the ground temperature variety of layered in geothermal recovery process accurately.
{"title":"Discussion on geothermal recovery process of deep borehole heat exchanger in layered stratum","authors":"F. Chen, Yujie Bai","doi":"10.23977/jemm.2022.070105","DOIUrl":"https://doi.org/10.23977/jemm.2022.070105","url":null,"abstract":"To explore the characters of geothermal recovery process of deep borehole heat exchanger, a geothermal recovery process was simulated to explore the difference in stratum temperature distribution change under layered model and uniform model. The results indicated that the geothermal recovery rate is sharp at first and slow down then. The outlet temperature would be higher in the next heat extraction stage if the longer geothermal recovery period was adopted. Considering the time cost during the geothermal recovery period, the suggesting proportion of heat extraction and geothermal recovery could adopt 1:1. In addition, the uniform model cannot reveal the ground temperature variety of layered in geothermal recovery process accurately.","PeriodicalId":32485,"journal":{"name":"Journal of Engineering Mechanics and Machinery","volume":"157 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68787839","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}
Pub Date : 2022-01-01DOI: 10.23977/jemm.2022.070103
Lifang Zhang, Qiang Ma
Wind turbine blade is the key component of wind turbine to realize wind energy capture, so it is necessary to verify the rationality of blade structure design through full-scale structural fatigue test. In order to improve the test accuracy and efficiency, this paper proposes to establish the dynamic analysis model of the multi-degree of freedom system of the tested blade by using the finite beam element to realize the calculation method of the load amplitude of the biaxial fatigue test and integrate the dynamic analysis model and the target load calculation method into the particle swarm optimization algorithm to realize the optimization of the load distribution of the biaxial resonant full-size structure fatigue test. Through the design of a biaxial resonant loading scheme of 2.5MW-52.5m wind turbine blades, the results show that this method can quickly and accurately adjust the optimization parameters such as the position of the exciter and the motion quality of the exciter in the flapwise and edgewise on the premise that the fatigue cumulative damage caused by the test load is not less than the cumulative damage of the target load.
{"title":"Load Distribution Optimization Method for Fatigue Test of Full-scale Structure of Biaxial Resonant Wind Turbine Blade","authors":"Lifang Zhang, Qiang Ma","doi":"10.23977/jemm.2022.070103","DOIUrl":"https://doi.org/10.23977/jemm.2022.070103","url":null,"abstract":"Wind turbine blade is the key component of wind turbine to realize wind energy capture, so it is necessary to verify the rationality of blade structure design through full-scale structural fatigue test. In order to improve the test accuracy and efficiency, this paper proposes to establish the dynamic analysis model of the multi-degree of freedom system of the tested blade by using the finite beam element to realize the calculation method of the load amplitude of the biaxial fatigue test and integrate the dynamic analysis model and the target load calculation method into the particle swarm optimization algorithm to realize the optimization of the load distribution of the biaxial resonant full-size structure fatigue test. Through the design of a biaxial resonant loading scheme of 2.5MW-52.5m wind turbine blades, the results show that this method can quickly and accurately adjust the optimization parameters such as the position of the exciter and the motion quality of the exciter in the flapwise and edgewise on the premise that the fatigue cumulative damage caused by the test load is not less than the cumulative damage of the target load.","PeriodicalId":32485,"journal":{"name":"Journal of Engineering Mechanics and Machinery","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68787783","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}
Pub Date : 2022-01-01DOI: 10.23977/jemm.2022.070401
Yifei Zhang, Youjia Feng, Liyi Yang
: Connect the two metal balls with a rubber band, then twist the rubber band and put the metal ball on the table. The ball will start to rotate in one direction and then in the other. This strange phenomenon is similar to the so-called "pendulum" movement. This paper makes a theoretical and experimental study of this phenomenon, and explores the relevant parameters that affect the motion, such as the type of rubber band, the material of the contact surface, and the size of the metal ball.
{"title":"The Ball on the Rubber Band","authors":"Yifei Zhang, Youjia Feng, Liyi Yang","doi":"10.23977/jemm.2022.070401","DOIUrl":"https://doi.org/10.23977/jemm.2022.070401","url":null,"abstract":": Connect the two metal balls with a rubber band, then twist the rubber band and put the metal ball on the table. The ball will start to rotate in one direction and then in the other. This strange phenomenon is similar to the so-called \"pendulum\" movement. This paper makes a theoretical and experimental study of this phenomenon, and explores the relevant parameters that affect the motion, such as the type of rubber band, the material of the contact surface, and the size of the metal ball.","PeriodicalId":32485,"journal":{"name":"Journal of Engineering Mechanics and Machinery","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68788267","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}
Pub Date : 2022-01-01DOI: 10.23977/jemm.2022.070106
Wen-ying Chen, Jingyu Li
For a class of network control systems with both data packet dropout and network communication delay problems, a new robust model predictive control method with compensation function is proposed. Considering that the system has interference problems, in the two cases of long-delay and short-delay, the packet loss problem is established as a Bernoulli sequence, and then a discrete NCS model based on the state observer is obtained. The state observer in the model can deal with the data packet dropout compensate and predict the state of the long-delay problem. Through linear matrix inequality and Lyapunov method, the controller is designed to obtain sufficient conditions for the closed-loop system to be exponentially stable and meet the specified performance indicators. Finally, compared with the method without any compensation measures, the method in this paper can get better control effect.
{"title":"Design of H∞ Predictive Controller for Networked Control System","authors":"Wen-ying Chen, Jingyu Li","doi":"10.23977/jemm.2022.070106","DOIUrl":"https://doi.org/10.23977/jemm.2022.070106","url":null,"abstract":"For a class of network control systems with both data packet dropout and network communication delay problems, a new robust model predictive control method with compensation function is proposed. Considering that the system has interference problems, in the two cases of long-delay and short-delay, the packet loss problem is established as a Bernoulli sequence, and then a discrete NCS model based on the state observer is obtained. The state observer in the model can deal with the data packet dropout compensate and predict the state of the long-delay problem. Through linear matrix inequality and Lyapunov method, the controller is designed to obtain sufficient conditions for the closed-loop system to be exponentially stable and meet the specified performance indicators. Finally, compared with the method without any compensation measures, the method in this paper can get better control effect.","PeriodicalId":32485,"journal":{"name":"Journal of Engineering Mechanics and Machinery","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68787919","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}
: The durability of vehicle structure is one of the important performances to evaluate the quality of automobiles, and it has been paid more and more attention by automobile manufacturers and consumers. In the whole vehicle development process, automotive structural durability testing is essential. With the advantages of high test accuracy and short test cycle, road simulation test has become an effective test method in the vehicle development stage. Among them, the spindle-coupled road simulation test can most comprehensively reproduce the excitation of the road to the vehicle. The relevant test technology is synchronized with the rapid development of automotive products and keeps pace with the times, becoming one of the most deeply cultivated test technologies in the industry.
{"title":"Overview of Spindle-Coupled Road Simulation Test Method for Vehicle Structure Durability","authors":"Guang Yanga, Zhiqiang Zhaob, Zhihui Niuc, Yong-Fu Wangd","doi":"10.23977/jemm.2022.070303","DOIUrl":"https://doi.org/10.23977/jemm.2022.070303","url":null,"abstract":": The durability of vehicle structure is one of the important performances to evaluate the quality of automobiles, and it has been paid more and more attention by automobile manufacturers and consumers. In the whole vehicle development process, automotive structural durability testing is essential. With the advantages of high test accuracy and short test cycle, road simulation test has become an effective test method in the vehicle development stage. Among them, the spindle-coupled road simulation test can most comprehensively reproduce the excitation of the road to the vehicle. The relevant test technology is synchronized with the rapid development of automotive products and keeps pace with the times, becoming one of the most deeply cultivated test technologies in the industry.","PeriodicalId":32485,"journal":{"name":"Journal of Engineering Mechanics and Machinery","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68788116","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}
Pub Date : 2022-01-01DOI: 10.23977/jemm.2022.070309
Zhuang Sun, Hongyan Zhang
: In order to study the stress intensification effect of pipe elbow in the secondary stress check, the U-shaped pipeline commonly used in engineering was taken as the research object. The experiment platform for analysing pipe elbow stress was established, and the maximum stress with the displacement load was measured and compared with the results of the finite element analysis results and ASME B31.3 Code. On this basis, a correction formula calculating the Stress Intensification Factor (SIF) of elbows was proposed, and the influence of the wall thickness and the bend radius on the elbow stress distribution was studied. The results showed that pipeline displacement significantly affects stress for pipe bends, the stress of the elbow increased with in-plane displacement load. To ensure structural integrity for reliable working conditions for piping components, pipe displacement needs to be considered when designing bends. On this basis, a modified formula for calculating the SIF of in-plane elbow is proposed. Compared with the ASME code formula, this formula is closer to the actual stress value of the elbow due to considers the influence of pipe displacement on elbow stress. The stress value of the elbow obtained by finite element analysis essentially in agreement with the experimental value, and the average error is less than 5.16%. With simultaneous increase in bend radius and wall thickness there is a reduction in SIF. When either of the above parameters is increased on, and keeping others constant the SIF decreases. The influence of pipeline displacement on SIF is more for short bend radius and its effect decreases with increased bend radius.
{"title":"Analysis of Elbow Stress Intensification Factors for Piping System","authors":"Zhuang Sun, Hongyan Zhang","doi":"10.23977/jemm.2022.070309","DOIUrl":"https://doi.org/10.23977/jemm.2022.070309","url":null,"abstract":": In order to study the stress intensification effect of pipe elbow in the secondary stress check, the U-shaped pipeline commonly used in engineering was taken as the research object. The experiment platform for analysing pipe elbow stress was established, and the maximum stress with the displacement load was measured and compared with the results of the finite element analysis results and ASME B31.3 Code. On this basis, a correction formula calculating the Stress Intensification Factor (SIF) of elbows was proposed, and the influence of the wall thickness and the bend radius on the elbow stress distribution was studied. The results showed that pipeline displacement significantly affects stress for pipe bends, the stress of the elbow increased with in-plane displacement load. To ensure structural integrity for reliable working conditions for piping components, pipe displacement needs to be considered when designing bends. On this basis, a modified formula for calculating the SIF of in-plane elbow is proposed. Compared with the ASME code formula, this formula is closer to the actual stress value of the elbow due to considers the influence of pipe displacement on elbow stress. The stress value of the elbow obtained by finite element analysis essentially in agreement with the experimental value, and the average error is less than 5.16%. With simultaneous increase in bend radius and wall thickness there is a reduction in SIF. When either of the above parameters is increased on, and keeping others constant the SIF decreases. The influence of pipeline displacement on SIF is more for short bend radius and its effect decreases with increased bend radius.","PeriodicalId":32485,"journal":{"name":"Journal of Engineering Mechanics and Machinery","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68788190","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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