Advanced Materials Research Vol. 859

Abstract: This article optimized hydraulic torque converter CFD simulation and pointed out the critical factors of influence to accuracy such as grid cell quality generation, fluid viscosity-temperature characteristic, improved simulation result illustrate there was only 5% accuracy deviation from real data tested which completely meets engineering application requirement.

Abstract: A great deal of experiments have been carried out in this study to reveal the effect of the water-binder ratio and fly ash content on the workability and strengths of GHPC (green high performance concrete). The workability of GHPC was evaluated by slump and slump flow. The strengths include compressive strength and splitting tensile strength. The results indicate that the increase of water-binder ratio can improve the workability of GHPC, however the strengths of GHPC were decreased with the increase of water-binder ratio. When the fly ash content is lower than 40%, the increase in fly ash content has positive effect on workability of GHPC, while the workability begins to decrease after the fly ash content is more than 40%. The addition of fly ash in GHPC has adverse effect on the strengths, and there is a tendency of decrease in the compressive strength and splitting tensile strength of GHPC with the increase of fly ash content.

Abstract: A large number of experiments have been carried out in this study to reveal the effect of the steel fiber dosage on the mechanical properties of HPC (high performance concrete). The mechanical property includes compressive strength, elastic modulus and flexural strength. The results indicate that the addition of steel fiber increase the compressive strength, elastic modulus and flexural strength of HPC. When the steel fiber dosage is less than 2%, these mechanical property parameters are increasing gradually with the increase of steel fiber dosage, while these parameters begin to decrease when the steel fiber dosage is more than 2%. With the development of HPC, the application of steel fibers in HPC becomes more and more popular. In the actual construction of steel fiber reinforced HPC, the dosage of steel fiber should be controlled strictly in order to ensure that the steel fibers can perform their best improvement on high performance concrete.

Abstract: Crack width, deflection and load bearing capacity of two-span concrete continuous beams partially prestressed with unbonded carbon fiber reinforced polymer (CFRP) tendons can be calculated accurately, the first premise is to calculate reasonably the stress increment of CFRP tendons. However, the law of stress increment of unbonded tendons is unclear. Moment-curvature analysis method and deformation compatibility condition were used to compile nonlinear full-range analysis programs of this kind of continuous beam. The comparison between simulated results and tested results of stress in CFRP tendons indicates that the simulation analysis programs are reliable.

Abstract: The pin-on-disk wear test and solid particle erosion test were used to investigate the wear resistance property of both high chromium white cast iron and multi-component white cast iron with optimal alloy compositions and heat treatment conditions. Experimental results indicate that a linear relationship between the wear lose and the testing time exists for high chromium white cast irons. Apparent scratch grooves and sheared pits appeared on the specimen surface. Subsurface observations found pit depths of some 4.5~8.0 mm. Crack propagation routes were clearly visible along the martensitic grain boundaries for alloys in the as-quenched state. Tempering treatment increases the toughness of the alloy, resulting in an increase in the resistance to crack formation. On the other hand, the multi-component white cast irons exhibited a non-linear relationship between the wear lose and the testing time. Relatively shallow scratches were found on the specimen surface, and pit depths of about 4.0 mm were observed through subsurface observations. Tempering at 570°C caused a reduction in hardness of the alloy, and therefore, the fracture mode tends to be ductile. As a result, deformation only occurred in crater regions with no clear evidence of spreading.

Abstract: Based on the previous results on the experimental study of shear performance of high-strength concrete beam and the application of mathematical statistics theory, the page establish the shearing strength formula of high strength concrete beams under concentrated load . Comparing regression formula and GB50010-2010 calculated value with the experimental results respectively, it shows that the ultimate strength calculated by regression analysis matches with the experimental results well, but GB2010 calculated results is unsafe.

Abstract: The bridge simplified two-dimensional plane beam element model, Simplified to two degrees of freedom quarter vehicle model, The entire bridge system is divided into two subsystems vehicle and bridge, Using separate equations of motion of vehicles and bridges, Proposed bridge systems numerical solution of coupled vibration analysis, The law at the wheel in contact with the deck displacement compatibility conditions for a balanced relationship with the interaction force associated, At each time step using the Newmark-β integration scheme, Through this paper the numerical solution results do comparison with the literature, the results show that the proposed method is reliability and validity.

Abstract: Ground-roll is an interferential wave existing widely in seismic data, and it is an important step in seismic data processing to suppress ground-roll. Wavelet Transform lacks of detecting the singularities of the signal with straight line or curve, and the method can separate the different waves at the same time because of Curvelet transform simultaneously has the characteristics of frequency and direction. The experiment results show that the Curvelet transform has better effects in ground-roll suppression.

Abstract: Nowadays,there are a large number of mining tailings in China,ore tailings not only pollute the environment,but also consume plenty of land resources,even threat the safety of people's life.In this article ,researches have been done to gradation of grain of tailings in QinHuangdao by the test,and compressive strength and loss on ignition with different volume of tailing concrete.

Abstract: This paper discusses the possible surface subsidence and deformation of the overlying rock during the underground coal gasification (UCG) process, which is an important part of feasibility studies for UCG operations. First coal seam roof movement and surface subsidence in the shallow UCG process were simulated by a finite element model coupled with heat transfer module in COMSOL. Numerical results from this model were compared with and in good agreement to the existing studies. This was followed by the development of model for deeper coal seam cases. The comparison of the numerical results from two models shows that surface uneven settlement in deep underground coal gasification is only 7% of that in shallow underground coal gasification.