Advanced Materials Research Vols. 1044-1045

Abstract: This paper studies the influence on compressive strength, freezing resistance and microstructure of cement mortar with different content of mica in stone powder, in the tests, manufactured sand with high content of mica and natural river sand were mixed with different proportion, and the content of stone powder was the same in mixed sand. Experiment results indicate that, with the increasing of mica content in stone powder, 28d and 60d compressive strength of cement mortar decreases obvious, mass loss rate and strength loss rate with 50 freeze-thaw cycles increase a little. Microstructure of cement mortar with higher content of mica is not compactly by SEM, the internal defects of cement hardened pastes could be increased because of the flake mica which surface is smooth, and it will cause the spread of micro crack.

Abstract: Dynamic stability analysis is a very important research project in the space structures. Up to now, in most researches, the imperfections of members are not included in the dynamic stability analysis for the single-layer lattice domes. In this paper, using multiple-beam method to simulate the initial bending deformation of the members, the dynamic stability behavior of a Kiewitt-8 single-layer lattice dome under three dimensional earthquake actions is analyzed by considering the member imperfections and the initial geometrical imperfections. The influence of member imperfections to the dynamic stability behavior of the structure is investigated.

Abstract: Combined with the Beijing Business Center (CBD) core district Z14 plots commercial finance project (hereinafter referred to as the "CBD project") foundation pit construction, introduces the deep foundation pit of bored pile reinforcement cage fabrication and erection construction technology. In the construction process, through the site set up a special steel processing and production platform, the localization of the flange and other measures to solve the steel reinforcement cage positioning and connection construction difficulties. Combining the engineering fact, detailed calculation process of lifting steel cage hanging position, lifting machinery and hoisting rigging selection, and through the ANSYS software of finite element analysis and put forward specific measures to ensure the quality of steel reinforcement cage.

Abstract: The motion equation of the grinding cylinder is deduced, which is based on the dynamic analysis of the grinding cylinder of the ball mill coupled with vertical vibration. Numerical model of vertical vibration ball mill is built and used to study the motion of grinding cavity media and grinding efficiency. The simulation results show that the distribution status of the grinding media in each region is changed, the grinding fragmentation of the grinding media to the material is enhanced, and the efficiency of fine grinding is improved with the coupled vertical vibration in a ball mill.

Abstract: For high speed trains running at 300km/h or more, the aerodynamic noise becomes the primary noise source. A good knowledge of the location, spectral characteristics and propagation behavior of the noise source and the corresponding methods to reduce the effect of the aerodynamic noise are of crucial necessity during the design process of the high speed train. Based on the Lighthill Analogy, the pressure fluctuation of air at the surface of the train is acquired by simulating the flow field of a CRH3 high speed train running at 200 km/h, 300 km/h, 400 km/h and 500km/h by means of large eddy simulation method. By Fourier transformation, the distribution and the spectral characteristics of the surface acoustic dipole sources are obtained. The analysis of the results shows that the aerodynamic noise of the high speed train is a broadband noise with a strong radiation power band from 50Hz to 1000Hz. The dipole acoustic power calculated by statistically averaged on train surface is found to be proportional to the sixth power of running speed of the high speed train. The first and second bogie, the inter-car gap, the air deflector of the power train and the train nose of the last wagon are the main noise sources that contain high radiation energy.

Abstract: In order to acquire mechanical performance of High cap supporting frame-shear structure, in view of the sea high cap supporting frame-shear theory analysis and numerical simulation of structure is less, this paper performs numerical simulation analysis for pile caps-soil-the upper structure using the finite element software ANSYS. Expression equation of wave force is given, and three-dimensional finite element model is established. By Analysis the deformation and stress of pile foundation and pile caps under different load combinations are obtained, and the deformation, bending moment of pile top, axial force are checked, finally the feasibility of the system is verified, and these can provide a reliable basis and reference for reasonable design of offshore structures. High cap supporting frame-shear structure for its strong adaptability is widely used in offshore construction system.

Abstract: The Steady flow simulation to selected the delta wing model for different angles of attack in the Maher number.The law of flow field changes with the angle of attack is gotten.Through the FLUENT simulation,The variation tendency of coefficient of lift and drag in the different angle of attack is gotten.Further reveals the change rule of Maher number, pressure, velocity and other parameters in the different angle of attack.With increasing angle of attack, Maher number distribution is sparse of the same position increases and the greater numerical.the distribution of velocity vector is sparse of the same position increases and the greater numerical.the pressure distribution is sparse of the same position increases and the greater numerical.

Abstract: Lift joints can cause problems related to insufficient adhesion of new concrete to old. In this paper, show the possibility to avoid the formation of the lift joints with long breaks of concreting by lifts by delaying the initial setting of cement in concrete. Three types of cement retarders was tested: based on salts of phosphoric acid, based on the calcium gluconate and based on the modified technical lignosulfonates. Research has shown that can be avoided the lift joints in case the concreting breaks up to a 1 day in by using retarding layer between the old and the new concrete.

Abstract: Based on new energy efficiency design standards of Beijing and specific project, this paper focuses on finding reasonable design solution for EEERB to realize the 4^th energy efficiency target by diagnosing energy efficiency and judging thermal performance.

Abstract: Wind actions on the structures consist of two parts, the average action and the fluctuation action. The fluctuation action will cause the structures vibrating and enlarge the wind action of the structures. This paper investigates the wind vibration coefficient for the single layer lattice barrel vault structures. In the analysis, the simulation velocity-time curve of wind is developed and the finite element methods are used to analyze the wind-induced vibration responses of the lattice barrel vault structures. The influence of the rise to span ratio, the length to width ratio of the structure, and the different average velocity of the wind are investigated. Based on the numerical analysis results, the formula of the wind vibration coefficient for the single layer lattice barrel vault structure is suggested for the wind resistance design of the structures.