Applied Mechanics and Materials Vols. 687-691

Abstract: The oil spill will directly affect the measuring accuracy of the gear flowmeter, so use the computational fluid dynamics software to calculate the leakage regulation of the internal gear flowmeter is one of the important things. Based on Pumplinx, when the end clearances of the gear flowmeter were 0um, 10um, 20um, 30um, 40um and 50um, the corresponding numerical analysis of spillage was carried out. From the results of numerical analysis, with the increase of the end clearance, the leakage amplification will also increase. In practical work, we should control the end clearance of gear flowmeter strictly while the gear works normally.

Abstract: Helically coiled water pipe is widely used in industry, agriculture and other areas. But few researches have been done on its internal secondary vortex rotational phenomenon. In this paper, the helically coiled water pipe was simulated by CFD software. The secondary vortex structure and its rotational development process in typical cross-sections, and the secondary flow velocity distribution, the axial velocity distribution were researched by numerical simulation. The realizable k-ε model with swirl correction was selected to solve governing equations. It is found that the secondary vortices positions are 45° symmetry in turbulent condition within the range of its working flow rate. The secondary vortices positions vary from vertical symmetry to 45° symmetry when the internal flow of helically coiled pipe translates from laminar condition to turbulence condition. In addition, with the curvature radius increasing, the flow rate that the positions of secondary vortices vary to 45° symmetry will grow up.

Abstract: Aiming at the ZA type automotive synchronous belt, natural frequency of transverse vibration of automotive synchronous belt is analyzed theoretically by using model of string vibration, and ZA type automotive synchronous belt with belt length 400mm is analyzed by using ANSYS-WORKBENCH software. Solving natural frequency of belt under preload, the results are compared with the theoretical calculation results, and to verify the theoretical calculation results. It provides a basis to design multi-pulley driving system and reduce transverse vibration of synchronous belt in the process of transmission.

Abstract: We investigate the quantum ratchet effect in a triple delta-kicked model. Three symmetric flashing potentials alternately act on a particle with a symmetric and homogeneous initial state of zero momentum. Ratchet currents emerge when quantum resonances are excited. Ratchet currents in the triple model may be stronger than those in the previous model. Our work expands upon the quantum delta-kicked model and may contribute to experimental investigation of the quantum transport of cold atoms.

Abstract: In order to analyze the explosion characteristics on the free field performance of thermobaric explosive, parameters of blast waves produced by the investigated charges in an open space were measured by the use of piezoelectric sensors and the results were compared to traditional TNT. Moreover, a numerical simulation of TBE explosion in free field was performed within the frame of AUTODYN. Comparison with TNT reveals that the values of peak pressure and impulse of TBE are higher than that of TNT due to the secondary reaction of Al and detonation products. It is found that the simulation results of TBE detonation blast wave parameters coincided very well with the experiment data. This demonstrates that the simulation method used is an effective way to depict the spreading of detonation waves in free field for TBE.

Abstract: The nose landing gear is a vital component of an aircraft,which has an important impact on the safety of the aircraft.This paper studies the system of nose landing gear steering on the basis of the gear and rack mechanism durability test of a certain type of civil aircraft landing gear steering. Furthermore,it puts forward a method of passive loading,which can simulate the friction when the nose landing gear reciprocating turning,and establishes the mathematical model. The simulation results show that the simulator can meet the requirements of load,and laid a theoretical foundation for the subsequent actual work.

Abstract: Global path planning is quoted in this paper. The stoical and global environment has been given to us, which is abstracted with grid method before we build the workspace model of the robot. With the adoption of the ant colony algorithm, the robot tries to find a path which is optimal or optimal-approximate path from the starting point to the destination. The robot with the built-in infrared sensors navigates autonomously to avoid collision the optimal path which has been built, and moves to the object. Based on the MATLAB platform, the simulation results indicate that the algorithm is rapid, simple, efficient and high-performance. Majority of traditional algorithms of the path planning have disadvantages, for instance, the method of artificial potential field is falling into the problem of local minimum value easily. ACO avoids these drawbacks, therefore the convergence period can be extended, and optimal path can be planned rapidly.

Abstract: Pro-active head restraint is a new automotive safety device. It can make a pre-estimation of the occurrence possibility of rear-end collision. Thus, the whiplash injury can be effectively reduced or even prevented. One of the key elements in rear-end collision avoidance system is to establish an effective safety distance mathematical model. Based on the running state of front car, the related calculation models of safety distance are established by means of dynamical and kinematical analysis of vehicle braking process and following process. Taken randomness of parameters into consideration, the fuzzy relations between these parameters should be validated by means of fuzzy theory. By using the MATLAB software, the study shows that safety distance model and the methods used to determine parameters are reasonable, and the false alarm can be effectively minimized.

Abstract: The characteristics of different grade of iron ore concentrate slurry are different, which causes confusion in pulp conveying process. Therefore, aiming at the problem of accelerated flow wear the pipeline, further propose the accelerated flow elimination technique to reduce the pipeline wear caused by accelerated flow, and ensure the safe operation of iron concentrate pipeline. The production practice shows that the technique can effectively inhibit the accelerated flow phenomena and ensure the different grade of iron concentrate without mixing in conveying, at the same time minimize the pipe wear.

Abstract: This paper introduces the concept of chaotic systems with complex variables,and add the time-delay part.The idea is that the number of effective state variables can be increased by treating the real and imaginary parts separately.On the basis of the Lyapunov stability theory,a scheme is designed to realize the new form of chaotic synchronization,and we demonstrate how chaotic complex systems with time-delay in a master–slave configuration can be synchronized to a constant scaling matrix.The speed and accuracy of the synchronization are illustrated by means of computer simulation.