Applied Mechanics and Materials Vols. 121-126

Abstract: As the plant areas of blueberries expand unceasingly, the realization of harvesting mechanization becomes more and more urgent. The fruit collection devices of the picking machine are designed with three-dimensional software Pro/E based on the blueberry picking machine. Meanwhile, wind sorting is used to realize the separation of fruit and leaves. In this paper, wind-sorting box is studied on the basis of the principle of wind sorting. The simulations of wind-sorting box inner are made with software FLUENT. A reliable basis is provided for the feasibility of wind sorting and a further analysis is made for the shape and the position of the inlet of wind-sorting box. And the structure of wind-sorting box is optimally designed. The improvement of the efficiency of wind sorting not only provides a theoretical basis for the separation of fruit-leaves of small berries, but also has an important meaning in agricultural machinery.

Abstract: In order to avoid avalanche propagation in engineering change that is high-risk and high-cost, two methods for the detection of avalanche propagation were proposed. Firstly, analyzed the reasons for the avalanche propagation and its main features: constraint conflict and/or a great many affected elements. Then, the methods for the detection of those two features based on directed graph and complex networks respectively were proposed. Finally, the experiment of managing a type of transmission was employed to validate our method and it showed the correctness of the proposed method.

Abstract: Oil source made up of constant pressure variable displacement pump, accumulator, and pipeline is widely used to provide stable pressure for electro-hydraulic control system in practical engineering. Based on the experiment, the relationship between initial charging pressure & volume of the accumulator at inlet of the servo valve and control precision is analyzed in detail, and coupling rules between the load variation and the pressure fluctuations of oil-source are obtained, the rules can give reference for selecting initial charging pressure & volume of the accumulator according to the requirement of system control precision, which can further improve control precision and product quality by optimizing equipment parameters.

Abstract: Experiments were carried out to investigate the tribological properties of spherical plain bearings with copper grid composite liners filled PTFE under two contact pressures(40MPa,60MPa), four oscillating frequencies (1.2Hz, 1.8Hz, 2.4Hz, 3.0Hz) and two swinging conditions. With the help of SEM, EDS and Three-dimensional morphology profiler, the wear mechanism was analyzed. The results indicate the coefficients and wear depths under tilt swinging condition are higher than those of swivel swinging. While the friction temperature show the contrary trend. The research discovers that the friction temperature has a great influence on tribological properties of spherical plain bearings. The analysis demonstrates that the main wear mechanisms are the adhesive and abrasive wear under the two swinging conditions and extrusive wear exist also.

Abstract: For some special active magnetic bearings (AMBs) application occasions that demand the rotor isolated from external environment, especially when a metal layer is added, other sensors besides differential transformer displacement sensor (DTDS) can not used to detect the rotor displacements. Before being used, the impact factors and relevant extents on the DTDS performances are analyzed on the basis of magnetic and electrical properties the added metal layer between the DTDS core and the measured object. The DTDS performance with and without metal layers are separately simulated on the platform of MATLAB and ANSOFT. And then the DTDS with metal layers are applied to a five-DOF AMB test bed. The research results show that the sensor sensitivity has decreased 8.18% and cutoff frequency decreased 5%, while the linearity increased 38.7%. Despite of those changes, the rotor can also be stably suspended and rotated at 30 000r/min in the five-DOF AMB system.

Abstract: In this paper, the influencing factors of springback for air-bending of sheet metal are introduced. The bending springback in various process parameters is simulated with a ABAQUS FEA software. The influence of different parameters on bending springback is investigated and some effective methods for predicting and restricting sringback are put forward.

Abstract: Based on the interaction between nano-fiber and eutectic interphase, forth-phase mode is used to get the mechanical stress field of matrix in eutectic composite ceramics. The effective flexibility increment tensor of eutectic ceramic composite is obtained by the volumetric average strain. The remote stress boundary condition of the eutectic composite ceramis is accounted for getting the mechanical stress field in matrix. The results show the mechanical stress field of the matrix is associated with the stiffness and the volume fractions of each component in eutectic composite ceramic , the shape of interphase and nano-fiber. The stresses in matrix will decrease due to the strong constraining effects of the eutectic interphase. The eutectic interphase make the eutectic composite ceramics strengthen.

Abstract: This paper adopts the method labor time standard, in the development environment of VC++, using Access database storage costs data, and the cost results output into Excel, developed mechanical product turning processing manufacturing cost estimation system. Using this system can realize turning processing cost estimation and feedback the cost information of mechanical product turning processing, make a design personnel to understand the cost information, to improve design, reduce the cost, improve the market competitiveness of products

Abstract: The large spatial reticulated structures belong to vibration and defects sensitive structures when vibrations will be easily produced under dynamic loading actions, and dynamic failure accidents will be caused. The application of the piezoelectric smart material in structural vibration control was researched with the shaking table test of active seismic control simulation of the spatial reticulated shell model structure.The results show that the piezoelectric actuators optimally arranged can effectively decrease earthquake responses of the structure, so it is a good active seismic control method.

Abstract: Canal control algorithm is very import in the process of water delivery. The paper presents a parameters-self-adapting canal flow fuzzy P+PR control according to the merits of fuzzy-control and the features of P+PR control algorithm through fuzzy inference method. The model uses the canal automation history control experiences to realize the optimization of parameters and make the control process always running in the optimal state. The parameters of fuzzy rule-table are built, the solution processes are deduced. The simulation results show that the overshoot is reduced significantly, and the dynamic behaviors are improved by using this adaptive fuzzy P+PR control model.