The Study on the Control of the Early-Stage Crack of the Concrete Poured in Winter in Shenyang Subway

2013 ◽  
Vol 671-674 ◽  
pp. 1135-1139 ◽  
Author(s):  
Li Han ◽  
Wen Zhao ◽  
Yu Zhao
Keyword(s):  
Temperature Stress ◽  
Civil Engineering ◽  
Early Stage ◽  
Difficult Problem ◽  
Construction Quality ◽  
Concrete Crack ◽  
Combination Of Methods

The control of concrete crack is a complicated and difficult problem for civil engineering. It is more difficult to control the crack of the concrete poured in winter. Thorough the analysis of the construction of Shenyang subway in winter, a combination of methods are applied. Frost proof and decreasing the temperature stress of concrete are considered together. The combination of antifreezing measures and decreasing the temperature stress of concrete make the construction quality arrive a satisfying level.

Research on early Concrete Crack Control of Shijiazhuang Subway Construction in Winter

2014 ◽  
Vol 580-583 ◽  
pp. 1134-1137
Author(s):  
Xiang Mei Yu ◽  
Li Jun Cao ◽  
Dong Yang Geng
Keyword(s):  
Temperature Stress ◽  
Civil Engineering ◽  
Difficult Problem ◽  
Construction Quality ◽  
Concrete Cracking ◽  
Crack Control ◽  
Concrete Crack ◽  
Subway Construction

The control of concrete cracking is a complicated and difficult problem for civil engineering. It is more difficult to control the cracking of the concrete poured in the winter. Thorough the analysis of the construction of the Shijiazhuang subway in winter, several methods are integrally applied. Frost proof and decreasing the temperature stress of concrete is considered together. The construction quality of the concrete arrive a satisfied level and the cracking of the concrete is successfully handled.

The Influence of Raft Foundation Temperature Stress Calculation by Radiation Condition

2014 ◽  
Vol 1021 ◽  
pp. 100-104
Author(s):  
Li Jun Zhao
Keyword(s):  
Temperature Stress ◽  
Radiation Condition ◽  
Influence Of Temperature ◽  
Stress Calculation ◽  
Concrete Crack ◽  
Raft Foundation ◽  
Calculational Method ◽  
Calculation Results

Raft foundation was researched in this paper,basing on the traditional “Wang Tiemeng Method”,the influence of temperature stress calculation by radiation condition was put forward emphatically. According to analysis the two calculation results, obtains the more precise temperature stress calculational method. Consequently the of concrete crack calculation and analysis result can be more precise and reliable.

Research on Temperature Stress for Contacts Reliability of Electric Connector

2014 ◽  
Vol 945-949 ◽  
pp. 1082-1085
Author(s):  
Yong Ying Du ◽  
Zhi Li Sun
Keyword(s):  
Temperature Field ◽  
Temperature Stress ◽  
Transfer Functions ◽  
Early Stage ◽  
Field Analysis ◽  
Contact Pair ◽  
Temperature Structure ◽  
Electrical Connector ◽  
Electric Connector ◽  
The Impact

Temperature induced degradation is a widely recognized failure phenomenon.However, the basic mechanisms that control the onset and progression of such behavior are not well understood and are a topic of considerable interest in the electrical connector community. In this paper, the simulation analysis of temperature field on this topic are described. The distribution graph of temperature field for the electrical connectors and the highest temperature of the surface of electrical connector was achieved by analyzing a single blade/receptacle contact pair FEA model. A mathematical model was developed that related the early stage temperature levels for the connectors.Additionally, the thermal deformation caused by the temperature had little effect on the contact stress based on temperature - structure coupling field analysis for the electrical connector, the impact of temperature on the electrical connector was mainly reflected in the rate of oxidation of the metal surface. The failure physical process of the electric connector was drawn under temperature stress through the model and theory analysis for the electrical connector , and reliability growth program of the electrical connector was achieved under the temperature influence. The same transfer functions for one type of contact pair were obtained from the simulation, and the results showed that for this limited system, finite element modeling and analysis have great potential for evaluating the influence of design variations on degradation behavior.

scholarly journals Effect of Reinforcement on Early-Age Concrete Temperature Stress: Preliminary Experimental Investigation and Analytical Simulation

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Jianda Xin ◽  
Siqing Lin ◽  
Nannan Shi ◽  
Jianshu Ouyang ◽  
Dahai Huang
Keyword(s):  
Reinforced Concrete ◽  
Temperature Stress ◽  
Testing Machine ◽  
Early Age ◽  
Principle Of Superposition ◽  
Stress Development ◽  
Concrete Crack ◽  
Analytical Simulation ◽  
Concrete Temperature ◽  
Early Age Concrete

For concrete under short-term loading, effect of reinforcement on concrete crack resistance capability is usually negligible; however, recent research results show that extension of this viewpoint to concrete under long-term loading (temperature variation) may be unsuitable. In order to investigate this phenomenon, this paper presents the experimental and analytical results of early-age reinforced concrete temperature stress development under uniaxial restraint. The experiments were carried out on a temperature stress testing machine (TSTM). Experimental results show that the coupling of reinforcement and concrete creep behavior influenced the concrete temperature stress development, and nearly 16% of concrete stress was reduced in the current research. Moreover, the cracking time of reinforced concrete was also delayed. Finally, based on the principle of superposition, analytical simulations of effect of reinforcement on concrete temperature stress have been performed.

scholarly journals Development of Innovative Methods for the Assessment of the Technical Condition of the Gearboxes of the Mine Belt Conveyors in the Parameters of the Lubricating Oil

2019 ◽  
Vol 297 ◽  
pp. 03006 ◽  
Author(s):  
Mariya Mamaeva ◽  
Evgeniy Kuzin
Keyword(s):  
Early Stage ◽  
Optical Emission ◽  
Technical Condition ◽  
Lubricating Oil ◽  
Actual Condition ◽  
Innovative Methods ◽  
Combination Of Methods ◽  
Belt Conveyors ◽  
Wear Products ◽  
The Cost

This article shows that a significant part of the cost of coal is the cost of transporting it from the long wall to the mine surface, which makes it important to search for reserves in order to increase the efficiency of using mine vehicles, in particular, belt conveyors. This article proposes a method for diagnosing the state of gears of mine belt conveyors based on the actual condition of the lubricating oil. The advantages of combining the study of oil parameters by spectroscopic and microscopic methods are shown. The results of testing lubricating oil of the mine gearboxes located on belt conveyors installed in a single transport and process chain. In order to determine the concentration of wear products the oil was examined with an optical emission spectrometer. For lubricating oil, in which excess wear was observed, a microscopic examination was carried out to clarify the types of wear. Micrographs of wear particles in lubricating oil are given. It characterizes one or another type of wear or their combination. This particular combination of methods increases the probability of identifying possible malfunctions of gearboxes at an early stage of defect development. Thus, the introduction of this technique will reduce the duration of unplanned emergency downtime of belt conveyors and improve the safety of mine transport.

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