Advanced Materials Research Vols. 532-533

Abstract: The hydraulic property of Circulating Fluidized Bed Combustion (CFBC) ashes has a significant impact on their treatment and re-utilization. The studies on several CFBC ashes show that the hydraulic property of them is obvious, and even the hydraulic rate is so fast that CFBC pastes can harden within several hours after molding. The influencing factors of hydraulic property of CFBC ashes are investigated. The results confirm that the content of the free lime and the high-activity components has great influence on the hydraulic property of CFBC ashes.

Abstract: To study the Volute of Variable Geometry Turbocharger (VGT) flow field and the possibility of providing the basis theory for control strategy and matching with engine, in this paper, a method is presented. The 3D viscous compressible flow in the model of volute and the vanes is simulated by CFD using FVM (Finite Volume Method). And taking some VGT as an example, the simulation is carried out. The result shows that the method can display the distribution of pressure and velocity in the model clearly. The zone and the reasons resulting in loss will be found after analyzing the results, and then the turbocharger can be optimized and redesigned purposeful to reduce the losses resulted from improper figure. The distribution of pressure and velocity at open and close vanes will be found after analyzing the results, and the basis theory for VGT control strategy and matching with engine can be provided.

Abstract: In view of PTP high precise timing requirement for many application fields, GPS time service is provided with the advantages of high precision and high stabilization. The principle and timescale of PTP based on GPS are analyzed and discussed. And then a PTP time synchronization platform with GPS-based UTC time is designed and implemented, the correlative key design flowchart is described as well. Finally, the paper gives the experiment results, which show the time synchronization accuracies can reach nanosecond range.

Abstract: In order to verify correctness of two-dimensional axisymmetric finite element model, this paper carries out axial symmetry analysis of the steel ball shell by ANSYS software and 2-D finite element model is established. The radial and tangential stress distribution is acquired, through comparison with the theoretical solution, both are in good agreement. So it is feasible to simulate the three-dimensional model by finite element axisymmetrical two-dimensional model.

Abstract: Laser device is an important apparatus that have been widely applied in various fields. The paper classified the laser device according to the different of working material forms and discussed the main characteristics. Main constitute of laser device is working material and excitation source. Adjusting measures of the resonant cavity is quite important for laser device, the author detailed discussed the operation procedure. As to the maintenance of the cooling system, the author also discussed the manipulate steps.

Abstract: It is very important to carry out research of dynamic performance and acquire data of bridge. it can provide reference for design of bridge. Combined with a bridge in actual engineering, this paper analyzes the deformation of bridge subjected to vehicles with different velocities. Based on typical theory on vibration analysis between bridge and vehicles and simplified model, finite element model of simple-supported bridge is established by ANSYS software, and concrete process of modeling, solving, analyzing and dealing is introduced. Through the numerical simulation analysis dynamic response characteristics of the bridge body are acquired when the vehicle passes through the bridge at different speeds, variable regularity is given for dynamic response and these can provide good reference for controlling the vibration measures of bridge under moving loads.

Abstract: In this study, molecular dynamics (MD) simulation has been employed to investigate the distribution function of gyration radius under different temperatures. The structure of chloroprene rubber (CR) was constructed and the circles of energy minimization were applied. The fitting functions of normal stress with time under different pressures were obtained. Compression stress relaxation experiment of different temperatures was also conducted. Comparing with the coefficient of stress relaxation from the experiment, it was found that the theoretical stress relaxation results were similar to the experimental data. The results indicated that the mean-square radius of gyration decreased with reduction of temperature, which corresponded to the typical viscoelasticity stress relaxation behaviors of polymers. It is confirmed that the variation of mean-square radius can be used to quantitatively describe the stress relaxation of rubber system and a good agreement between the theoretical curves with the experimental data can be obtained from MD simulation.

Abstract: Indirect finite element method was used to analyze the thermal - structural coupled field of cooling tube with grid plate, and the process of finite element modeling, loading and solution were given. Cooling grid tube deformation shape and node radial deformation curve were obtained by finite element analysis and the deformation increases gradually from pipeline inner wall to the outer wall, so the nonlinear performance is significantly. Deformation of grid plate increases linearly, and the maximum and minimum deformation are respectively for 0.32mm and 0.22mm. Diameter, axial and hoop stress distribution of cooling gate can be obtained, and the results show that heat transfer result in structure internal stress, radial stress is the state of compression at the place of cooling grid and pipeline Interchange, the axial stress is the state of compression in the middle of a cooling grid, the hoop stress is pressure at the wall of pipeline and tension at grid plate.

Abstract: Reinforced concrete and Prestressed concrete T-beam bridge are widely used because they have the features of good economy and easy construction in bridge construction. However, with the increase in traffic and the growth of hours of operation, diseases like the increase of the deflection in this bridge,the more cracks,etc.,are being emerging gradually.According to the disease of Chun Ma Bridge while that is being used, we have made a detailed analysis,and proposed purposeful measures to deal with the disease as well as the design to reinforce the bridge,solved the problem of the safety in the bridge operation. This article have made a good in-depth discussion and analysis on the T-beam retrofitting,and it will have a guidance significance for the similar bridges in the future.

Abstract: The flutter derivative is the important basic tache of bridge flutter stability analysis. Taking the Liujiaxia Bridge in Gansu province as the research object, this dissertation studies the impaction of damping ratio on the flutter derivatives and the critical wind speed through different series of section model vibration test. The results showed that the change of vertical bending and torsional damping ratio have no obvious regular influence on the eight flutter derivatives. But the changing of vertical bending and torsional damping ratio have the greatly impact on the critical wind speed at 0° and -3° angle of attack. When it is at 0° angle of attack ,the vertical bending damping ratio ζ_h is increased by 23%,the torsional damping ratio is increased by 0.63%, the flutter critical wind speed is increased by 4%;when the ζ_h is increased by 1.04%, the ζ_α is increased by 0.87% , the flutter critical wind speed is increased by 7%. When it is at -3° angle of attack, the vertical bending damping ratio remained around 0.8%, the torsional damping ratio is increased from 0.65% to 1.05%, the flutter critical wind speed is increased by 14%; when the ζ_α is increased from 0.65% to 2.05%, the flutter critical wind speed is increased by 24 %.When it is at +3 °angle of attack, the vertical bending and torsion damping ratio have little effect on the flutter critical wind speed.