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Scientific Bulletin of Valahia University Materials and Mechanics最新文献

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Studies Regarding the Reaction Method to Wear Braking Mechanism 磨损制动机理的反应方法研究
Scientific Bulletin of Valahia University Materials and Mechanics Pub Date : 2017-04-25 DOI: 10.1515/bsmm-2017-0007
I. Petre, A. Poinescu, A. Catangiu, S. Mihai
{"title":"Studies Regarding the Reaction Method to Wear Braking Mechanism","authors":"I. Petre, A. Poinescu, A. Catangiu, S. Mihai","doi":"10.1515/bsmm-2017-0007","DOIUrl":"https://doi.org/10.1515/bsmm-2017-0007","url":null,"abstract":"Abstract With the development of industry have made efforts to improve the performance of braking systems of motor vehicles on public roads. The choice of materials used for coupling brake system involved the development of new materials that meet safety requirements in circulation. During braking of any vehicle, due to the friction created between the disk and pad, temperature rise occurs with negative effects on the process of slowing down the vehicle. Mechanical and thermal stress being put on the brakes is very high. Due to overheating, brake discs and pads may warp or crack, and the material they are made may their change its structure. These defects give rise to vibrations and noise during braking, to reduce the coefficient of friction, reduce the effectiveness of the braking mechanism. This paper proposes a study regarding the thermal stresses effects of brake mechanism on the disc material of a car Dacia Logan. It proposes a theoretical model to calculate the temperature that occurred during the operation of the braking system and experimental analysis on the influence of temperature on the brake disc material.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"18 1","pages":"37 - 42"},"PeriodicalIF":0.0,"publicationDate":"2017-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83521421","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
Data Scattering in Strength Measurement of Steels and Glass/Epoxy Composite 钢和玻璃/环氧复合材料强度测量中的数据散射
Scientific Bulletin of Valahia University Materials and Mechanics Pub Date : 2017-04-25 DOI: 10.1515/bsmm-2017-0002
A. Catangiu, D. Ungureanu, V. Despa
{"title":"Data Scattering in Strength Measurement of Steels and Glass/Epoxy Composite","authors":"A. Catangiu, D. Ungureanu, V. Despa","doi":"10.1515/bsmm-2017-0002","DOIUrl":"https://doi.org/10.1515/bsmm-2017-0002","url":null,"abstract":"Abstract The strength of materials is a complex function which involve two main components, material nature and the presence of defects. Usually glasses exhibit a fragile behavior due to a numerous flaws and the effect is a large range of data scattering in tensile strength measurement. The Weibull probability density function was applied to describe the scatter of experimental data in tensile test, which emphasize a difference between variance in case of tensile strength of three stainless steel grades and glass epoxy composite. The main goal is mathematical modeling of those distributions and finding of equations which predict the probability of failure for a sample subjected to a specific stress.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"69 1","pages":"11 - 16"},"PeriodicalIF":0.0,"publicationDate":"2017-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90292922","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: 11
Mechanical Characterization of Nanostructured Thin Films Used to Imporve Mechatronic Components 用于改进机电元件的纳米结构薄膜的力学特性
Scientific Bulletin of Valahia University Materials and Mechanics Pub Date : 2017-04-25 DOI: 10.1515/bsmm-2017-0009
L. Badita, G. Gheorghe, V. Bratu, Valentin Gornoavă, Marian Vocurek, A. Zapciu, I. Munteanu
{"title":"Mechanical Characterization of Nanostructured Thin Films Used to Imporve Mechatronic Components","authors":"L. Badita, G. Gheorghe, V. Bratu, Valentin Gornoavă, Marian Vocurek, A. Zapciu, I. Munteanu","doi":"10.1515/bsmm-2017-0009","DOIUrl":"https://doi.org/10.1515/bsmm-2017-0009","url":null,"abstract":"Abstract Taking into account the importance of mechatronic applications, researches regarding the possibility to improve the lifetime of mechatronic components were made. Nanostructured metallic thin films (Ti, Cr, Al and Ti/Al multilayer) were deposited on different types of steel substrates, because nanomaterials have exceptional properties in relation to the common materials. In this paper a part of the results obtained after mechanical and topographic characterization of the thin films are presented. Cr is the deposited thin film showing the highest hardness on the surface of steel substrate type OSC. After the scratch tests realized, Ti layer presented the best adhesion on all types of steel substrates used in experiments. The results of these researches could be extremely useful for engineers in the mechatronic field.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"35 1","pages":"48 - 54"},"PeriodicalIF":0.0,"publicationDate":"2017-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87871467","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
The Influence of Cooling Rate on Structure of EN AC 5083 Aluminum Alloy 冷却速率对enac5083铝合金组织的影响
Scientific Bulletin of Valahia University Materials and Mechanics Pub Date : 2017-04-25 DOI: 10.1515/bsmm-2017-0001
M. Popescu, B. Varga
{"title":"The Influence of Cooling Rate on Structure of EN AC 5083 Aluminum Alloy","authors":"M. Popescu, B. Varga","doi":"10.1515/bsmm-2017-0001","DOIUrl":"https://doi.org/10.1515/bsmm-2017-0001","url":null,"abstract":"Abstract In this paper it was studied the structure of EN AC 5083 aluminum alloy depending on cooling conditions. By cooling curves recorded for different casting conditions there were calculated the cooling rate (vr). The structural analyzes, performed by Image Pro-Plus 6.0 software, allowed both be highlighted structural particularities of various conditions for casting and establishing the correlation: lg d = lg v + n (where d is the dendritic parameter).","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"17 1","pages":"10 - 7"},"PeriodicalIF":0.0,"publicationDate":"2017-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79010306","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
Structural Transformations During Tempering in the Steels with High Content of Mo and Co 高Mo、Co含量钢回火过程中的组织转变
Scientific Bulletin of Valahia University Materials and Mechanics Pub Date : 2017-04-25 DOI: 10.1515/bsmm-2017-0003
F. Anghelina, D. Ungureanu
{"title":"Structural Transformations During Tempering in the Steels with High Content of Mo and Co","authors":"F. Anghelina, D. Ungureanu","doi":"10.1515/bsmm-2017-0003","DOIUrl":"https://doi.org/10.1515/bsmm-2017-0003","url":null,"abstract":"Abstract The structural transformations occurring at tempering for some high-speed steels are a subject of research for which have been dedicated numerous studies. More complex compositions of the high-speed steels were direct consequence of the complexity of structural transformations which occur during heat treatment. On the other hand, current tendency in energy requires maximum efficiency and rational use of heating sources used in industry. Thus, only a precise knowledge of the kinetics of transformations occurring at tempering can be a basis for optimizing this treatment. Although cobalt is used for a long time as an alloying element, though relatively recently it was considered important to the properties of rapid steel. These circumstances, combined with the lack of quantitative information on the kinetics transformation at tempering operation treatment for some steel has led to this paper. The thickness of the studied samples is 5 mm and was taken from the annealed steel bars. These samples were subjected to hardening and tempering treatment in salts bath. Heating for hardening was performed in two steps, at 5500C and 8300C. Austenitizing was done at 12000C, during 120 seconds. The cooling was done up to 5300C in salts bath, with a keeping of 15 seconds, and then air cooling was done. On these samples were carried out, HRC Rockwell hardness measurements, and X-ray diffraction analysis.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"53 1","pages":"17 - 21"},"PeriodicalIF":0.0,"publicationDate":"2017-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81890006","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 Mathematical Model Applied to Solidify and Segregation of Ledeburite Tool Steel Ingots 莱氏体工具钢锭凝固偏析的数学模型
Scientific Bulletin of Valahia University Materials and Mechanics Pub Date : 2017-04-25 DOI: 10.1515/bsmm-2017-0005
V. Bratu, I. Popescu
{"title":"The Mathematical Model Applied to Solidify and Segregation of Ledeburite Tool Steel Ingots","authors":"V. Bratu, I. Popescu","doi":"10.1515/bsmm-2017-0005","DOIUrl":"https://doi.org/10.1515/bsmm-2017-0005","url":null,"abstract":"Abstract In order to determine the optimum geometry of the ingot mold format (the format of ingot mold with a diameter per height ratio H / D <3 and the conicity of minimum 7%) was analyzed by mathematical modeling of solidification and segregation of the carbon and sulfur in it. It was considered 205Cr115 steel type (according with , STAS 3611 - Romanian stardandization) and known also as X210Cr12 steel type (according with European standard). It has been considered an element of volume of coordinates x, y, z in the solidifying ingot and have made the following assumptions: (i) the equilibrium distribution ratio K, is applied to the solid-liquid interface; (ii) solid diffusion is negligible during solidification; and (iii) the solid density is constant during solidification. In carrying out the simulation of segregation mechanisms are resolved heat transfer equation, that simulating the solidification process and are are solved the interdendritic fluid equation of motion.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"42 1","pages":"28 - 31"},"PeriodicalIF":0.0,"publicationDate":"2017-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88080348","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
On the Assessment Mode of Some Safety Coefficients Using Breaking Polynomial Criteria 基于破多项式准则的安全系数评估模式
Scientific Bulletin of Valahia University Materials and Mechanics Pub Date : 2017-01-25 DOI: 10.1515/bsmm-2017-0006
R. Iatan, Pavel Florescu, Carmen T. Popa, G. Tomescu
{"title":"On the Assessment Mode of Some Safety Coefficients Using Breaking Polynomial Criteria","authors":"R. Iatan, Pavel Florescu, Carmen T. Popa, G. Tomescu","doi":"10.1515/bsmm-2017-0006","DOIUrl":"https://doi.org/10.1515/bsmm-2017-0006","url":null,"abstract":"Abstract Starting of the characteristic expressions of some breaking polynomial criteria, known and used in practice, it is highlighted how to assess the safety coefficients used in some practical cases. It is obvious that the decision belongs to the user given the experience in the adequate technical domain. In this regard it must not neglect the fact in that the breakage is produced most often in unpredictable moments, conditioned by multiple factors, dependent on material, on manufacturing technologies of finished products, respective the operating conditions.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"2 1","pages":"32 - 36"},"PeriodicalIF":0.0,"publicationDate":"2017-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80361764","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 Stability of Longitudinal Movement During the Transportation of Industrial Oversized Equipment on a Platform with an Even Number of Axles. General Case 工业超大设备在双轴平台上运输时纵向运动的稳定性。一般情况下
Scientific Bulletin of Valahia University Materials and Mechanics Pub Date : 2017-01-25 DOI: 10.1515/bsmm-2017-0008
R. Iatan, M. Stătescu, Cristina Salca
{"title":"The Stability of Longitudinal Movement During the Transportation of Industrial Oversized Equipment on a Platform with an Even Number of Axles. General Case","authors":"R. Iatan, M. Stătescu, Cristina Salca","doi":"10.1515/bsmm-2017-0008","DOIUrl":"https://doi.org/10.1515/bsmm-2017-0008","url":null,"abstract":"Abstract It is known that the transportation of oversized technological equipment raises particular poroblems, both from the economical and technicall point of view. Knowing the loads in the platform-equipment assembly, the intensity and the direction of the wind loads, the condition of roads and the way these act is imperative. The present paper seeks to determine the expression of the loads obtained on a platform with an even number of axles, loaded with a technological equipment and neglecting or not the deformation of the suspensions and tires.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"191 1","pages":"43 - 47"},"PeriodicalIF":0.0,"publicationDate":"2017-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79773816","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
Theoretical Model Used in Monitoring the Losses from Water Networks Due to Water Control Measurement Batteries 水控测量电池对水网损失监测的理论模型
Scientific Bulletin of Valahia University Materials and Mechanics Pub Date : 2017-01-25 DOI: 10.1515/bsmm-2017-0010
V. Andrei, Cornel Marin, A. Negrea
{"title":"Theoretical Model Used in Monitoring the Losses from Water Networks Due to Water Control Measurement Batteries","authors":"V. Andrei, Cornel Marin, A. Negrea","doi":"10.1515/bsmm-2017-0010","DOIUrl":"https://doi.org/10.1515/bsmm-2017-0010","url":null,"abstract":"Abstract According to the IWA norms, the water loss category includes also the apparent loss water due to measurement errors of the water meters used at the connections. This paper presents the experimental results obtained during two years of registrations in TARGOVISTE’s Water Company network. A program for verifying the water meters used for connections has been implemented according to a statistical distribution, depending on the number of appliances and their dimensions. Using a theoretical simulation model, calibrated on the basis of the actual reference flows measured on the metrology approved measuring stand, a procedure was developed to assess the level of deviations in the fully metered water distribution network. Depending on the values of deviations and flows actually recorded by the meters in the distribution network, it was possible to estimate the percentage of the losses from the actually used water meters.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"3 1","pages":"55 - 61"},"PeriodicalIF":0.0,"publicationDate":"2017-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87456104","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
Dental Cements 牙科水泥
Scientific Bulletin of Valahia University Materials and Mechanics Pub Date : 2017-01-01 DOI: 10.1515/bsmm-2017-0014
N. Angelescu, V. Bratu, E. Stoian, D. Ungureanu, A. Gurban
{"title":"Dental Cements","authors":"N. Angelescu, V. Bratu, E. Stoian, D. Ungureanu, A. Gurban","doi":"10.1515/bsmm-2017-0014","DOIUrl":"https://doi.org/10.1515/bsmm-2017-0014","url":null,"abstract":"Abstract Calcium-phosphate cements is one of the most popular types of biomaterials, both due to their specific properties of self - setting and of their superior biocompatibility. Although in general the phosphocalcic cements, which are the subject of the present paper, have somewhat lower mechanical properties than other biomaterials based on calcium and phosphorus, or even other dental cements of the same nature. The ceramic compositions presented in the present paper constitute a special category of biomaterials due to other notable advantages that characterize them. Thus, this category of materials is defined by a near-perfect adaptation to the surface of the biological tissue, as well as by a convenient resorption rate, processes followed by the generation of optimal bone formation. In this paper are presented principles of realization of the calcium-phosphate cements (raw materials and conditions of production), as well as the properties of these biomaterials, insisting, in particular, on the chemistry of the setting reactions. At the same time, informations regarding the possibilities of clinical use, such as implants are presented.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"6 1","pages":"25 - 27"},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75829730","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
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