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Acta Mechanica Slovaca最新文献

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Labyrinth Seal of Aircraft Turbine Engine Air Flow Calculation at High Viscosity 航空涡轮发动机的迷宫密封在高粘度下的气流计算
Acta Mechanica Slovaca Pub Date : 2020-08-22 DOI: 10.21496/ams.2020.011
M. Čížek, T. Vampola
{"title":"Labyrinth Seal of Aircraft Turbine Engine Air Flow Calculation at High Viscosity","authors":"M. Čížek, T. Vampola","doi":"10.21496/ams.2020.011","DOIUrl":"https://doi.org/10.21496/ams.2020.011","url":null,"abstract":"This paper describes a CFD calculation of aircraft turbine engine labyrinth seal. The geometry of labyrinth seal shows that the air flow is very viscous. Based on the CFD calculation it was prepared some analysis of Reynolds numbers, Mach numbers and total temperature with different rotational speeds. Based on this analysis it is possible to improve the standard design steps of labyrinth seals of aircraft turbine engines. It should be helpful for thermodynamic and aircraft engineers.","PeriodicalId":135905,"journal":{"name":"Acta Mechanica Slovaca","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126344899","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}
引用次数: 4
Influence of Cryogenic Temperatures on Mechanical Properties of Valve Seats of Internal Combustion Engines 低温对内燃机气门座力学性能的影响
Acta Mechanica Slovaca Pub Date : 2020-08-22 DOI: 10.21496/ams.2020.006
J. Mráz, B. Skrbek
{"title":"Influence of Cryogenic Temperatures on Mechanical Properties of Valve Seats of Internal Combustion Engines","authors":"J. Mráz, B. Skrbek","doi":"10.21496/ams.2020.006","DOIUrl":"https://doi.org/10.21496/ams.2020.006","url":null,"abstract":"Valve seats of internal combustion engines are used in cylinder heads, due to increase the strength and abrasion resistance of the intake and exhaust valve seats. Valve seats are made from alloy cast iron, high-alloy steels, wear-resistant alloys and seats made using powder metallurgy. The valve seats are pressed into the head. Some materials must be deep-frozen before pressing to reduce the pressing overlap. The overlap is large, in the order of tenths of a millimetre, due to the guaranteed seating of the seat in the cylinder head. The amount of overlap depends also on the material of the cylinder head. Liquid nitrogen (about -196 °C) is used for freezing. In our case, these are monometallic seats, made by technology of precision casting from cobalt alloys. A particular type of cobalt alloy uses the trade name STELLITE.","PeriodicalId":135905,"journal":{"name":"Acta Mechanica Slovaca","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126414901","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}
引用次数: 0
The Springback Prediction of Deep - Drawing Quality Steel used in V - Bending Process V形弯曲深拉优质钢回弹预测
Acta Mechanica Slovaca Pub Date : 2019-12-20 DOI: 10.21496/ams.2019.022
P. Mulidrán, E. Spišák, M. Tomáš, Vladimír Rohaľ, F. Stachowicz
{"title":"The Springback Prediction of Deep - Drawing Quality Steel used in V - Bending Process","authors":"P. Mulidrán, E. Spišák, M. Tomáš, Vladimír Rohaľ, F. Stachowicz","doi":"10.21496/ams.2019.022","DOIUrl":"https://doi.org/10.21496/ams.2019.022","url":null,"abstract":"In the sheet metal forming processes, the material, and in this case deep drawing quality steel DC06 exhibits springback effect, which is governed by strain recovery of material after the load removal. In this contribution, numerical simulation of a bending process was performed and compared with experimental data. The springback is related to many parameters like forming conditions, tool geometry and material properties such as sheet thickness, yield stress, work hardening, strain rate sensitivity and elasticity modulus. In this work, the influence of used material parameters is evaluated. The springback effect of V-shaped sheet metal part made of DC06 steel, with a thickness of 0.85 mm was investigated. Bending angle was set to 90°. In the numerical simulation, Hill48 and Barlat yield criterions were used in combination with Ludwik's and Swift's hardening models. Achieved data from the numerical simulations were compared and evaluated with experimental test results.","PeriodicalId":135905,"journal":{"name":"Acta Mechanica Slovaca","volume":"61 19","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120816614","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}
引用次数: 2
Development of the Device with a High Positioning Accuracy Serving for Residual Stress Quantification using Optical Methods 高定位精度光学残余应力定量测量装置的研制
Acta Mechanica Slovaca Pub Date : 2019-12-20 DOI: 10.21496/ams.2020.005
M. Pástor, P. Čarák, M. Hagara
{"title":"Development of the Device with a High Positioning Accuracy Serving for Residual Stress Quantification using Optical Methods","authors":"M. Pástor, P. Čarák, M. Hagara","doi":"10.21496/ams.2020.005","DOIUrl":"https://doi.org/10.21496/ams.2020.005","url":null,"abstract":"The paper describes some procedures required for functional verification of a newly designed unique positioning device developed to quantify residual stresses by modern optical methods with a combination of the hole-drilling method based on ASTM-E 837-13a American standard. The high precision of milling a circular groove or a hole belongs to essential requirements for achieving relevant results in the quantification of residual stresses using semi-destructive methods. At the beginning of the paper, the mechanical parts of the developed drilling device are briefly described. Subsequently, two analyses were realized and present in the paper. While the first one verifies the possibilities and accuracy of the cutter positioning in the vertical direction, the second one is focused on the investigation of the milled groove circularity. The results of both analyses are processed tabularly and prove the possibility to use the drilling device in residual stress analysis.","PeriodicalId":135905,"journal":{"name":"Acta Mechanica Slovaca","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124096519","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}
引用次数: 2
Low-Cost System for Managing of Tool's Storage 刀具库存管理的低成本系统
Acta Mechanica Slovaca Pub Date : 2019-12-17 DOI: 10.21496/ams.2019.018
Vladimír Sojka, P. Lepšík
{"title":"Low-Cost System for Managing of Tool's Storage","authors":"Vladimír Sojka, P. Lepšík","doi":"10.21496/ams.2019.018","DOIUrl":"https://doi.org/10.21496/ams.2019.018","url":null,"abstract":"Companies with custom production often need to store a lot of unique tools. Amount of these tools is always increasing. That can lead to problems with storing of these tools. Storages are often overfull and unorganized. In those cases, it takes a lot of time to find specific tool, and it is an issue which generates many other wastes. Because software solutions for storage management which can resolve this problem are expensive, companies cannot afford to buy them. This problem is calling for some low-cost solutions to manage these storages. Solutions cheap and simple that every company can afford to implement. This low-cost solution could be a system of storage control, based on paper cards with simple database. This article shows how to implement the card system to unorganized storage and how can this system improve storage management, establish order and reduce waste in storage. This all is proven by a case study in glass making company at storage of wooden forms for parts made by glassblowing, that study is also included.","PeriodicalId":135905,"journal":{"name":"Acta Mechanica Slovaca","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121443748","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}
引用次数: 0
Analysis of Mathematical Programming Applications in Supply Chain Management of Manufacturing Enterprises 数学规划在制造企业供应链管理中的应用分析
Acta Mechanica Slovaca Pub Date : 2019-12-17 DOI: 10.21496/ams.2019.002
L. Veselovská
{"title":"Analysis of Mathematical Programming Applications in Supply Chain Management of Manufacturing Enterprises","authors":"L. Veselovská","doi":"10.21496/ams.2019.002","DOIUrl":"https://doi.org/10.21496/ams.2019.002","url":null,"abstract":"This paper focuses on a current topic of supply chain management and operations research which serves as a tool manufacturing enterprises to cope with pressure put on them by continuously changing market conditions and global economy itself. Paper presents results of research conducted on sample file of Slovak manufacturing enterprises. The main aim of this paper is to explore the extent of utilization of mathematical programming as optimization methods in production practice in Slovakia to analyse possible relationship between enterprise’s size and used optimizing method. Representativeness of the sample file was confirmed by application of Pearson ́s chi-squared test (χ2 test) due to criterion of enterprise’s size. The results of this research have an implication for business practice and may serve managers in their decision-making process. In managerial practice enterprises have to deal with many different problems concerning their supply chains. The majority of them can be resolved using mathematical programming.","PeriodicalId":135905,"journal":{"name":"Acta Mechanica Slovaca","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114074660","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}
引用次数: 0
High-temperature Processing and Recovery of Decommissioned Electrochemical Cells and Batteries 退役电化学电池和蓄电池的高温处理和回收
Acta Mechanica Slovaca Pub Date : 2019-12-17 DOI: 10.21496/ams.2019.007
M. Čarnogurská, Miroslav Příhoda, Peter Kurilla
{"title":"High-temperature Processing and Recovery of Decommissioned Electrochemical Cells and Batteries","authors":"M. Čarnogurská, Miroslav Příhoda, Peter Kurilla","doi":"10.21496/ams.2019.007","DOIUrl":"https://doi.org/10.21496/ams.2019.007","url":null,"abstract":"The present article describes the processing and recovery of decommissioned electrochemical cells and batteries by means of high-temperature melting in a reducing atmosphere. The experiment was carried out using two samples weighing 15 and 20 kg. CaO was used as a slag-forming additive and carbon was used as a reducing agent. The results of the experiments carried out with an 80 kVA plasma reactor showed that the decommissioned electrochemical cells and batteries may be disposed of using the plasma melting technology and the resulting product may be further recovered. The recovery rate for the non-ferrous metal of interest (cobalt) is approximately 95 %. The article also presents the chemical analyses of the formed alloy about weight of 3.7 kg in first and 5.6 kg in second experiment. The vitrified slag and fly ash analysis was also performed. The volume production of syngas was 12 m∙h with LHV from 2.7 to 3.4 MJ∙m.","PeriodicalId":135905,"journal":{"name":"Acta Mechanica Slovaca","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115841470","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}
引用次数: 0
Innovation of Fuel Maps and Pre-Ignition Maps of Experimental Vehicle as a Part of Development for Control Algorithm of the HCCI Engine 作为HCCI发动机控制算法开发的一部分，实验车辆燃油图和预点火图的创新
Acta Mechanica Slovaca Pub Date : 2019-12-17 DOI: 10.21496/ams.2019.014
M. Puškár, M. Kopas, Dušan Puškár, J. Lumnitzer
{"title":"Innovation of Fuel Maps and Pre-Ignition Maps of Experimental Vehicle as a Part of Development for Control Algorithm of the HCCI Engine","authors":"M. Puškár, M. Kopas, Dušan Puškár, J. Lumnitzer","doi":"10.21496/ams.2019.014","DOIUrl":"https://doi.org/10.21496/ams.2019.014","url":null,"abstract":"The questions concerning fuel consumption and emissions of the motor cars is always topical with regard to increasingly stricter technical standards that are valid within the automotive industry. Application of an innovative combustion technology, which is known as the Homogenous Charge Compression Ignition (HCCI) offers a possible answer for a suitable solution of the above-mentioned problems. Combustion of the homogenous mixture runs at the same time in the whole combustion area of the cylinder, i.e. almost the whole volume of the fuel-air mixture is combusted. In this way is possible not only to save a fuel, but also to reduce engine emissions. However, application of the HCCI technology is connected with some basic technical problems because the self-ignition process is very complicated and demanding with regard to the process control. This article analyses the engine fuel maps and pre-ignition maps in order to quantify their influence on the fuel consumption and on the emission production. This research work is directly related to development of a control algorithm determined for the HCCI engine.","PeriodicalId":135905,"journal":{"name":"Acta Mechanica Slovaca","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125758986","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}
引用次数: 0
Ergonomics and the Musculoskeletal Disorders in the Work of Nurses 人体工程学与护士工作中的肌肉骨骼疾病
Acta Mechanica Slovaca Pub Date : 2019-12-17 DOI: 10.21496/ams.2019.011
Ľ. Dulina, I. Čechová, M. Krajčovič, M. Gašo
{"title":"Ergonomics and the Musculoskeletal Disorders in the Work of Nurses","authors":"Ľ. Dulina, I. Čechová, M. Krajčovič, M. Gašo","doi":"10.21496/ams.2019.011","DOIUrl":"https://doi.org/10.21496/ams.2019.011","url":null,"abstract":"Ergonomics in healthcare industry is still in its early stages. The role of healthcare personnel is to take care of population's health. This is why it is very important to care about healthcare personnel. First, this article is a presentation of a survey conducted in Slovakia. The survey focused on nurses working in inpatient departments. Therefore, the main objective was to verify the physical nursing workload and determine the most frequent musculoskeletal disorders of nurses. The survey was conducted by using the Nordic Questionnaire. The results of the survey confirm the most serious difficulties for nurses with a musculoskeletal apparatus. Moreover, the results also show pain-related dependence in one body part of a nursing professional depending on his or her profile. The second part of the article shows model situations that may occur in nursing work and the physical loading they impose on health of nursing professionals.","PeriodicalId":135905,"journal":{"name":"Acta Mechanica Slovaca","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132569290","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}
引用次数: 2
Computational Model of Rotary Engine Thermodynamic Cycle 旋转发动机热力循环计算模型
Acta Mechanica Slovaca Pub Date : 2019-12-17 DOI: 10.21496/ams.2019.012
Milan Drbal
{"title":"Computational Model of Rotary Engine Thermodynamic Cycle","authors":"Milan Drbal","doi":"10.21496/ams.2019.012","DOIUrl":"https://doi.org/10.21496/ams.2019.012","url":null,"abstract":"During the engine prototype design period the performance predictions are the key subject of the development. For the piston reciprocating engines a wide spectrum of the analytical approaches was developed as well as the numerical software (GT-Suite, Ricardo Wave etc.) is being used often. The increasing demand for the high-power output engines with a low displacement and weight for the UAV and marine applications, makes Wankel rotary engine a sensible option. The commercially available software for the performance prediction does not include required algorithms for the rotary engine calculation. This paper provides an approach to be used in the simulation model setup as well as the comparison of the simulation outcome with the measured data.","PeriodicalId":135905,"journal":{"name":"Acta Mechanica Slovaca","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131755742","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}
引用次数: 1
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