Papers by Keyword: Shearing Strength

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Authors: Fei Lin, Tie Peng Li, Lu Lu Sun, Qing Sen Meng
Abstract: In this investigation a study on vacuum diffusion bonding of as-extruded AZ31 magnesium alloys was carried out according to atomic diffusion theory. The bonding quality of the joints was checked by microstructure analysis, shear test and micro-hardness testing. The results showed that the diffusion temperature and holding time had a great effect on the the bonding quality of the joints. The maximum of joint shear strength was 76.2MPa with the bonding temperature being 420°C and the holding time reaching 90min.
Authors: Qian Fa Deng, Ju Long Yuan, Zhi Wei Wang, Dong Hui Wen, Xun Lv
Abstract: The most typical example of hard and brittle material is advanced ceramics, for its ultra-precision machining difficulty and wide applications, now it becomes a focus of attention. Semi-fixed abrasive plate (SFAP) is newly developed for preventing larger particles from doing workpiece surface damage in machining advanced ceramics, for larger particles from grain size dispersion or from outside of processing area could bring uneven load distribution on processing region of advanced ceramics. In this paper, Shearing strength, surface hardness and Young’s modulus as characteristics of SFAP are investigated. They were influenced by Grain size and abrasive weight ratio are analyzed and discussed, as well as the qualitative estimation of these influences on the characteristics of SFAP are deduced.
Authors: Xiao Yan Lin, Tong Lu Li
Abstract: The conventional shear creep apparatus uses lever to amplify the load, which has a serious limitations in practical use. First, the round and small shearing box can easily form an obvious stress concentration in the margin area. In addition, tilting of the lever can give an unreal vertical load in loading process. Aiming to solve the shortages of conventional apparatus, a new type of shear creep apparatus is introduced in this paper, whose loading system apply the pulley block, and shear box is changed from the round with the area of 30cm2 into the present square one with 10×10cm2. The new shear creep apparatus has more advantage compared with the conventional, and is more satisfactory to the need of test.
Authors: Zhi Tong Chen, Fei Lin, Jie Li, Fei Wang, Qing Sen Meng
Abstract: A study on vacuum diffusion bonding between as-extruded AZ31 magnesium alloy and 7075 aluminum alloy was carried out according to atomic diffusion theory. Recrystallization annealing was used for grain refinement of AZ31 magnesium alloy and 7075 aluminum alloy before the diffusion welding. The quality of the bonding joints was checked by shear test, micro-hardness test and microstructure analysis. Experimental results showed that the welding temperature and holding time have a great effect on the joint shear strength. The maximum of shear strength was 38.41MPa under the temperature of 470°C and the holding time of 60min. The result of micro-hardness measurement showed that the micro-hardness of welded joints was maximum. Three kinds of intermetallic compounds, Mg2A13, MgAl and Mgl7Al12, formed at the interfacial transition zone at 470°C.
Authors: Fei Lin, Jie Li, Hong Wei Zhao, Zhi Tong Chen, Qing Sen Meng
Abstract: Vacuum diffusion bonding of as-extruded AZ61 magnesium alloy was investigated according to atomic diffusion theory. The effects of the diffusion temperature and holding time on the quality of the bonding joint are investigated by means of microstructure analysis, shearing strength test and microhardness testing. The shearing test results showed that the maximum shearing strength reached 51.95MPa with the temperature of 470°C and the holding time of 90min. And the diffusion temperature and holding time have a great effect on the quality of the bonding joints. The microhardness measurement results showed that the microhardness value at the bonding joint was maximum.
Authors: Zhi Qing Li, Zhen Dong Cui, Yan Ping Wang, Li Chao Wang, Duo Zhong
Abstract: According to the typical loess in Shuozhou in Shanxi province, tests involved in compaction characteristics, shearing strength characteristics and disintegration are carried out by using loess and three kinds of improved loess, namely lime and fly-ash, lime and cement, cement and fly-ash. The best improved soil method is selected. The test results indicate that the compact hybrid structure is formed by fly ash and loess. The activity of fly ash is activated as a result of the lime mixing. A series of hydration reaction prompt the intensity of modified loess. And the physical and mechanical properties of improved loess are improved noticeably.
Authors: Jun Gu, Bao Lin Yang, Yi Jun Yang, Chao Ma, Ji Biao He, Ke Li
Abstract: In order to evaluate the impact of mud cake thickness on shearing strength at cement-formation interface accurately, a feasible simulation experiment system and evaluation method was established, which includes preparation of artificial core, formation of mud cake, maintenance of the samples and testing of the Shear bond strength of cement-formation interface. Based on this, by taking commonly used drilling fluid from Shuangjiang oilfield, Jinglou oilfield and Zhongyuan oilfield in China as examples, the laboratory impact evaluation results show that: (1) As for different drilling fluid system, the shearing strength at cement-formation interface of the cement-formation interface keeps a general tendency to an obvious decline as the growing of the mud cake thickness. (2) In the same drilling fluid system, though different in the time of maintenance, the variation trends that the shearing strength at cement-formation interface declines as the growing thickness of the mud cake are similar. (3) The declining rate of shearing strength at the cement-formation interface will reach 83.4 %-99.9 % when the mud cake thickness is 5mm. These developments of this paper can be used to optimize the design of drilling fluid and cementing technology, and consequently improve the cementation quality of cement-formation interface to meet the demands of highly-efficient petroleum production.
Authors: Qun Yang, Xu Li
Abstract: The double-layer pavement design with a combination of normal concrete layer and porous concrete overlay is the promising way towards tunnel pavement. This paper is aimed to confirm the optimal construction opportunity of porous concrete overlay based on the mechanical behavior of tunnel pavement. Parameters like compressive strength, shearing strength and tensile splitting strength were examined in laboratory and field experiment respectively. It is observed that the strength of the pavement gradually decreases with the increase of the construction time interval between the two layers. The results have revealed that the reasonable construction opportunity of porous concrete overlay should be controlled between the initial setting time and the final setting time of normal concrete layer.
Authors: Shao Peng Wu, Hong Wang, Jun Han, Jun Tao Lin
Abstract: The waterproof-adhesive layer plays an important role in cement concrete bridge pavement. The adhesive strength of the layer between the cement concrete deck and the asphalt pavement may affect the bridge’s service performance directly. In the study, the direct shearing-strength experiment between the asphalt pavement, waterproof adhesive layer and the cement concrete deck was done in a laboratory. Some testing parameters were considered, including different loading speed, surface processing mode of the cement concrete deck and adhesive materials. The result shows that the coarser the surface of the cement concrete deck is, the larger the shearing strength of the adhesive material is at the same temperature. The loading speed of the shearing test has important effect on the shearing strength. The rapid loading speed can cause high shearing strength. Especially, the experiment datum indicates that the relationship between the loading speed of the test and the shearing strength can be described using the power exponent. Ultimately, the study is aimed at providing bridge engineers with an efficient testing method that attempts to increase the prediction accuracy of adhesive strength for more reliable design.
Authors: Xi Xi He, Ye Lin
Abstract: Test & research on the shearing strength of the hollow mortar-less fabricated concrete block & masonry has been done in this article. A proposed formula has been put forward in this article by analyzing the influence of the shear loading methods on the shearing strength using the shearing test data of 27 standard test specimens’ continuous seams divided into 9 groups with 100% concrete infill ratio.
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