Papers by Keyword: Mechanical Performance

Abstract: Aluminum and aluminum alloy were widely used in various industrial fields,the key to application is the reliable welding. In this thesis,LF21 aluminum alloy brazing materials were designed and prepared by Orthogonal experiment,and mechanical properties of the brazing specimen was tested. Based on the GRNN(Generalized Regression Neural Network),Nonlinear relationship modle of brazing material preparation parameters and mechanical properties of the weldment was established.The results show that the model has better stability.When smooth factor value is 0.1,the network approximation error and prediction error absolute value is 0.01%.It can be realized that an nonliner mapping between the aluminum alloy brazing preparation parameters and solder joint tensil strenth based on the Orthogonal test and can do better prediction of the weld mechanical properties,according to brazing material preparation parameters.

Abstract: Stent placement has been a main approach to treat gastrointestinal diseases during past decade. Nitinol superelastic stents have been considered as a solution to such difficulties as restenosis after implantation, low twisting ability, inadequate radial mechanical strength and inappropriate dynamic behaviors associated with the ducts. In this paper, effects of A_f temperatures on mechanical performance of z-shaped Nitinol wire stent under crimping test for clinical applications are investigated by finite element simulation. Having 60% crimping and high radial resistive strength, favorable superelastic behaviors are attained at A_f temperature of 22°C. The performance of the stent is seen to be drastically different with a mere change of 1° in the segments angle.

Abstract: This research highlights the constructive features of Juniperus thurifera timber visible in the Western Mediterranean (from the island of Sardinia to Morocco). The use of this material is above all related to vernacular and traditional architecture, in the coastal areas as well as in the interior of the analyzed countries. An initial taxonomy of its use presents us with the issue of understanding the main structural performance of this type of timber, focusing in particular on its structural use and behavior. The results, visible throughout the research, are related to the resistance of the timber and its performance. On the other hand, this raw material is valued in vernacular architecture because of its strength when exposed to sea water or harsh weather conditions. Juniper beams and pillars are the most frequent solutions, but the use of branches and roots is also common, as the research demonstrates. In this framework, the text underlines the results of the research based on a geographical survey of juniper as a construction material, and on the first attempts to study its mechanical performance.

Abstract: The increase of the strength of gray cast iron is mainly depended on alloying. However, with the improvement of strength, its processing performance will always decrease. So three different gray cast irons are studied in this experiment, including adding 0.1% Nb elements, adding 0.2% Nb elements and adding 0.3% Nb elements, to investigate the Nbs effect to the mechanical performance of gray cast iron, we adopt Dynamic Strain Amplifier to measure cutting force to evaluate processing performance, use Optical Microscope and Electron Microscopy observe each samples organization, explains the relationship between Nbs content and the mechanical and processing performance of gray cast iron from micro-level. Finally, we draw the conclusion: when the Nb comes to 0.3 percent, the appearance of E-type graphite and Nb carbide durum granular will greatly decrease its processing performance.

Abstract: Basalt Fiber Reinforced Polymer (BFRP) bar was deemed as a substitute material of steel bar owing to its strong tensile properties and corrosion resistance which is benefit to enhance the durability of reinforced concrete bridges. Based on the current research findings, the prospects of BFRP bar for the application to bridges were analyzed. It was concluded that BFRP bar had more widely application to bridges than steel bar owing to the advantages of BFRP bar in the mechanical performance of resisting the corrosion. Meanwhile, two key points of whether BFRP bar could be successfully applied to bridges were also discussed, i.e., the bond-anchorage properties between BFRP bar and concrete as well as the manufacturing technique of anchorage device of BFRP bar.

Abstract: The glulam is determined by, and therefore a representation of, a new kind of ecological structural materials. The aim of this study was to summarize the mechanical performance especially the flexural behavior of various kinds of glulam and the physical properties of their relevant original timbers including pseudotsuga menziesii, larch, Yi poplar, poplar, China fir, mongolian scotch pine and camphor. And then it established and analyzed the relationship between the two to contrast those timber species so as to provide engineers with some reference in selecting timber glulam.

Abstract: Magnetorheological (MR) elastomers are a new type of MR material. At present, most studies in this field are at laboratory stage, and practicability was rarely considered preparation of MR elastomer materials. Consequently, the existing materials with low overall properties cannot be applied in engineering. In this paper, the performance requirements for MR elastomers to be used in isolators were proposed. Then a type of practical MR elastomers for isolators was prepared, and its mechanical performance and MR effect were tested. The results show that the designed MR elastomers have high mechanical performance and high MR effect, and thus can be used in isolators.

Abstract: In order to strengthen the co-work performance between the steel plate and concrete, the anchorage construction of arrayed studs were welded on both sides of the plate according to a super high-rise building in Beijing. Eighteen specimens of embedded steel plate concrete shear walls with arrayed studs were tested by pushing out under monotonic loading in this paper. Some parameters, such as the thickness of the concrete wall, the thickness of steel plate, the diameter, the length and the amount of the studs and the rate of reinforcement for distributing bars in the walls were considered. The shear bearing capacity, load-slip relationship, strains of the steel plate and studs, mechanical properties and failure mode were analyzed. The effect of stud layout on the coordinate work of the concrete plate was studied. Results show that the shear bearing capacity is obviously improved by using smaller diameter studs or decreasing the distance between studs when the total area of studs is kept unchanged. The thickness of the steel plate has almost no effect on the shear bearing capacity. The ratio of the length to the diameter of the studs should be not less than 4. A simplified mechanics calculated method to estimate the shear bearing capacity of this kind of shear wall was put forward. And the calculated results are in good agreement with the experimental results.

Abstract: Types of asphalt mixture with different gradations and air voids were designed. Tests on their indirect tensile strength, compressive strength and resilient modulus of compression under single axle compressing were taken to study the effects of two forms of water immersion (hot water immersion and freeze-thaw split test) on asphalt mixtures mechanical performance and high temperature stability. Test results point out that water immersion decreased asphalt mixtures performance seriously and the effect of freeze-thaw split tests on asphalt mixtures performance is far stronger than that of hot water immersion. Asphalt mixtures performance is related with its gradation and percent air voids. Asphalt mixtures with different gradation are different in their percent air voids, suitable gradation can form framework and filling action obviously, so to yield mixture with suitable percent air voids and good water stability.

Abstract: This paper studied the mechanical performance of bamboo fiber reinforced concrete through a series of compression, splitting and flexural tests. The comparative variables are the length and volume ratio of the bamboo fiber. The test results show that concretes splitting tensile property has obvious improvement when bamboo fibers are added, but the enhancement to the compression property and flexural property is not obvious.