Mechanika最新文献_第8页

Using the Stress Concentration Factor in Determining the Fracture Toughness 用应力集中系数测定断裂韧性

IF 0.7 4区工程技术

Mechanika Pub Date : 2022-10-21 DOI: 10.5755/j02.mech.31226

Goksel Saracoglu

引用次数: 0

Numerical Modelling of Moisture Transport Between Two Enclosures Connected by a Tube 用管子连接的两个外壳间水分传输的数值模拟

IF 0.7 4区工程技术

Mechanika Pub Date : 2022-10-21 DOI: 10.5755/j02.mech.32166

Z. Staliulionis, G. Miliauskas, S. Mohanty, J. Hattel

{"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":null,"pages":null},"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}

引用次数: 0

Effects of Addition of Glass Fibers and SiC Particles on the Mechanical and Machinability Behaviours of Areca Fine Fiber-Reinforced Phenol Formaldehyde Composite 添加玻璃纤维和SiC颗粒对槟榔细纤维增强酚醛复合材料力学性能和切削性能的影响

IF 0.7 4区工程技术

Mechanika Pub Date : 2022-08-30 DOI: 10.5755/j02.mech.25443

Athijayamani Athijayamani, P. Muthusamy, Sidhardhan Susaiyappan

引用次数: 0

Research on Tribological Features of Brake Friction Materials - Com-parison of the Results Obtained with the Pin-On-Disc and Ball-Cratering Methods 制动器摩擦材料摩擦学特性研究——销盘法与球磨法结果比较

IF 0.7 4区工程技术

Mechanika Pub Date : 2022-08-30 DOI: 10.5755/j02.mech.31673

A. Borawski, D. Szpica, G. Mieczkowski

引用次数: 1

Optimization of Anti-Impact Energy Absorption Structure of Hydraulic Support 液压支架抗冲击吸能结构优化

IF 0.7 4区工程技术

Mechanika Pub Date : 2022-08-30 DOI: 10.5755/j02.mech.32032

Qiang Zhang, Bao-Gui Li, Runxin Zhang

引用次数: 0

Development and Comparative Evaluation of Reduced-scale Krauss Friction Tester based on Similarity Theory 基于相似理论的克劳斯摩擦试验机研制与比较评价

IF 0.7 4区工程技术

Mechanika Pub Date : 2022-08-30 DOI: 10.5755/j02.mech.32030

Zhenyu Wang, Jie Wang, Lining Wang, Yunhai Ma

{"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":null,"pages":null},"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}

引用次数: 0

Robot Workspace Optimization based on Monte Carlo Method and Multi Island Genetic Algorithm 基于蒙特卡罗方法和多岛遗传算法的机器人工作空间优化

IF 0.7 4区工程技术

Mechanika Pub Date : 2022-08-30 DOI: 10.5755/j02.mech.32035

Qingliang Zeng, Guangyu Zhou, Ji Shi, Yongqing Li, Yuanqiang Liu, Tianming Chen, Liang Wang

{"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":null,"pages":null},"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}

引用次数: 1

Analysis of the Wall Force on the Bubble Collapse of the Benzamide Based on Molecular Dynamics Simulation 基于分子动力学模拟的苯甲酰胺气泡崩塌的壁力分析

IF 0.7 4区工程技术

Mechanika Pub Date : 2022-08-30 DOI: 10.5755/j02.mech.29875

Wei Xu, Xiuli Wang, Jinhua Liu, Yuanyuan Zhao, Guohui Zhao, Wenzhuo Guo

{"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":null,"pages":null},"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}

引用次数: 0

A New Shear Locking-Free Quadrilateral Plate Element for Free Vibra-tion and Eigen-Buckling Analysis 一种用于自由振动和特征屈曲分析的新型剪切锁定自由四边形板单元

IF 0.7 4区工程技术

Mechanika Pub Date : 2022-08-30 DOI: 10.5755/j02.mech.30331

Wei XiaXIANGng, Z. Yao, Lina He

引用次数: 0

Profile Design and Performance Research of Hydrogen Circulation Pump in Fuel Cell System 燃料电池系统氢循环泵外形设计及性能研究

IF 0.7 4区工程技术

Mechanika Pub Date : 2022-08-30 DOI: 10.5755/j02.mech.31528

Huanle Zhai, Wei Li, Leilei Ji, M. Awais, Jiwei Li, Shuo Li

{"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":null,"pages":null},"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}

引用次数: 3