Advanced Materials Research Vols. 546-547

Abstract: Based on Discrete Element Method(DEM), movements of steel balls in ball mill were simulated by Particle Flow Code in three Dimensions (PFC 3D), the motion states of all steel balls and balls with one diameter were discussed respectively at different ball filling rate. The results indicated that steel balls moved from cascading motion gradually to throwing motion with the increasing of rotary speed rate, and became centrifugal motion after rotary speed rate exceeded certain value. When rotary speed rate unchanged, the translation speeds from cascading to throwing or from throwing to centrifugal motion accelerated as steel balls’ diameter decreased. The segregation of steel balls was more obvious with the rising of rotary speed rate and lead to steel balls’ lamination that big balls moved in the inner and small balls moved in outer layer of the mill. Lamination of steel balls is benefical to crush different size minerals and improve grinding efficiency.

Abstract: Based on Discrete Element Method(DEM), initial state models of steel balls were establisheded by Particle Flow Code in three Dimensions (PFC 3D), the initial void rate of steel balls at different filling rate were calculated. The results showed that at the same filling rate, the initial void rate of steel balls decreased as steel ball’s diameter decreased. The initial void rate of steel balls with one diameter and grading steel balls both increased gradully as ball filling rate increased, but the initial void rate of grading steel balls were smaller than that of steel balls with one diameter. The Stratification phenomenon will occur after steel balls in grading scheme reached to the initial equilibrium sates, that is, Large steel balls moved near the mill’s center, but small steel balls moved away from the mill’s center and close to the cylinder of mill, which is benifical to improve grinding effeciency.

Abstract: Mecanum wheel can provide a Omni-directional movement, so to design the academic profile of the Mecanum Wheel become the first problem to be solved. this paper make a projection of the Mecanum wheel to the set of planes that perpendicular to the wheel axes, Derivate the academic profile of the wheel. Use the data to build the model of the wheels. Then import the model to ADAMS to validate the equation we got. The simulation results indicate they have a good Omni-directional mobile performance.

Abstract: The task of timing system is countdown on a set date and showing the time from current date to the setting date to enhance people’s attention and sense of urgency. A kind of high-precision timing system is introduced. The system is controlled by single-chip microcontroller. High integration clock chip is used as clock module. System hardware design and software design are introduced. System hardware design includes design of clock module, its connection with single-chip microcomputer, and the design of display module. System software design includes the settings of single-chip serial port, its initialization, the reading and writing of the clock module, the countdown program and the display program. Compared with other timing system which consists of frequency demultiplication by multivibrator, this system is more stable and reliable. The accumulative error is zero when long-time running continuously. Because the system control module is simple, it is convenient to be developed and utilized. Practice shows that this high-precision timing system can meet practical needs well.

Abstract: On the base of modal synthesis theory, the self-compiling vehicle-bridge coupling vibration analysis program was used to analyze the vehicle dynamic response and passing vehicle riding comfort of cable-stayed bridge. Compared with the impact of different factors on vehicle riding comfort, this method provides a useful theoretical reference to correlated evaluation research and management maintenance. The influence of driving speed on comfort is not obvious. The research makes reference to correlated project evaluation in procedure and method.

Abstract: Since the importance of ship-radiated noise simulation in onshore simulation training and digital sonar development, we establish a mathematical model of ship-radiated noise on the basis of analyzing the causes and characteristics for each of its components, and then apply the model on simulating each signal component in turn. Additionally, for improving the versatility of the model while reducing the complexity of the simulation, a design method for specific frequency response filter based on window function is used to realize the simulation. The simulation results demonstrate the effectiveness of the approach.

Abstract: Support structure of UAV (Unmanned Aerial Vehicle) engine is the important support for UAV engine, playing a support role and bearing extremely complex load, so its lightweight, strength and dynamic characteristics have a great influence on high performance of UAV. This paper focuses on UAV having the requirement of high performance and stability to the support structure of engine, and uses the software of MSC.Patran and MSC.Nastran and topology optimization criterion to lightweight design and analysis the support structure of UAV engine under the premise condition of existing constraints. Then the static strength and modal are analyzed for the result of lightweight design, and the strength of the model and dynamic characteristics are verified.

Abstract: The laminar cooling process for the hot-rolled strip is very complex, and the identification of k related to the heat transfer is critical to improve the mathematic precision. So a study of heat transfer parameters is carried in the paper, and the proposed approach is based on the hybrid multi-intelligence technology, where the RBF neural networks, CBR have been used to obtain the parameter estimates. A number of tests using industrial data have been conducted where desired numerical results have been obtained.

Abstract: For the blades of the small wind turbine working under the conditions of Low-Reynolds, the air viscosity has relatively great influence on them. The design and calculation on thickness of airfoils were studied in order to raise its life and reduce weight. In the premise of strength, the lighter, the better. This paper studied the aerodynamic performance of the airfoil under the Low-Reynolds and analyzed fluid-structure interaction effect at Reynolds number 600,000 under three different attack angles. The numerical simulation approach addresses unsteady Reynolds-averaged N-S solutions and covers transition prediction for unsteady mean flows. The computational result and the analysis show that the fluid-structure interaction is an important issue to consider while designing the wind turbine blade. The results may provide technical reference for the further wind turbine design.

Abstract: Land wheel is an important part of vegetable transplanting machine, its strength directly affects the whole performance. In this paper, Three-dimensional model of land wheel was built by Solidworks and imported into ANSYS by interface module between Solidworks and ANSYS. The load was applied with rotation angular velocity in this study, the stress, strain and displacement of the land wheel of a vegetable transplanter in operation were obtained through static analysis on the land wheel with finite element method analysis of software ANSYS, the maximum deformation and stress occurred at the rim and the studs on wheel, the results of static stress analysis will provide theoretical basis for design of vegetable transplanter. 5 order post-processing was conducted on the wheel, natural frequency and mode shapes was obtained after calculating and analyzing, Considerations should be taken in keeping the frequency of the wheel different from that of ambient vibration, which provides references for avoiding resonance during test wheel's running.