Applied Mechanics and Materials Vols. 52-54

Abstract: Based on the characteristics of parameterized modeling technology, digital solid modeling of the parts of rubber-bar roller cotton harvester and virtual assembly of rubber-bar roller cotton-picking machine were established, The motion parameters curve of key parts were analyzed by dynamic simulating method. The results showed that cotton-picking machine could achieve high collect rate of cotton and low impurity rate at the 400-450 RPM and 0.83 m/s of working speed.

Abstract: For the noise problem of moving target in noisy space, This work is dedicated to developing a novel and promising solution based on the moving target tracking technology and the active noise control (ANC) technology. The development process began with the simplified sound field interaction model, the “auto position tracking near head space ANC” strategy has been proposed from the modelling study. Furthermore, the primary experimental system that consists of the acoustic positioning and tracking subsystem for tracking the control point and the ANC subsystem for generating the anti-noise signal is presented, with the emphasis on the development of the improved TDC-FXLMS ANC algorithm. Finally, the performance of the auto-position tracking near head space ANC device is evaluated by carrying out the primary experiments on an experimental evaluation system.

Abstract: In this study, beryllium bronze/steel composite plates were fabricated through explosive welding process using different ratios of explosive. Microstructures of the joint were examined, and then shearing strength, peeling strength, Bending tests and hardness measurements were carried out on the bonded specimens. Experimental studies show that, beryllium bronze and steel could be bonded with a good quality. The interface is wavy texture changing in turns from flat - wavelet - large wave - stable large wave beginning with initiation point. Grains near the interface are elongated parallel to the explosion direction. As the ratio of explosive increase, the amplitude and wavelength of wave are increased, which leads to the increasing of shearing strength and bonging strength. No shearing in the interface is seen from the tensile-shear tests and fracture take place in the low strength material. The bended specimens show that defects such as separation and tearing were not observed. Hardness is increased with increasing explosive ratio and the highest hardness values are obtained near the bonding interface.

Abstract: A kind of design scheme of intelligent vehicle control system based on infrared photoelectric sensor is introduced in this paper.The Freescale 16-bit single chip MC9S12DG128B is used as controller, 13 infrared photoelectric sensors are used for acquiring path information and the PID controll is used for steering control in the system. All these ensure the intelligent vehicle’s independent tracing. To improve the system stability and response speed, a suppressing interference method based on software and a simple and effective filter interference scheme based on hardware are put forward.

Abstract: This paper describes a detection system design method of hydrogen engine based on LabVIEW. In order to understand the characteristics and working status of hydrogen fuel engine, we have developed a set of hydrogen fuel engine test system. In the system, LabVIEW is used as the software and DAQ PCI-1802H is the hardware, which mainly realizes the collection, testing, comparison analysis of engine signals and its feature parameters. It has strong functions of signal analysis and processing as well as nice user interface.

Abstract: Through the external flow analysis of 200 km/h high-speed container flat wagon utilizing SST k- turbulence model, we got the surface pressure distributions, flow field, locomotive resistance, containers resistance and so on. The researches show that pressure drag dominates large resistance of high-speed container flat wagon; the size difference between locomotive and container as well as the gap between vehicles will complex the flow in return increase the total aerodynamic resistance of train; due to the influence of bottom flow, the pressure drag of middle container with bogies is smaller than without, but still large.

Abstract: For acquiring the data about how did the aircraft platforms environment impact on its equipment, designed a measurement system for measuring aircraft platform environment. How to select the measurement position, where did the system install and how to verify the system parameter measurement precision are introduced in this article. Finally, according to the using environment a environment test was designed to verify the environmental worthiness of the system.

Abstract: Aiming at the deficiencies of positioning accuracy and matrix operating complexity in the classical MDS-MAP locating algorithm in WSN, a distributed multi-dimensional scaling-MAP algorithm (MDS-MAP (D)) was proposed in this paper. In this algorithm, the distance of the nodes was quantified to obtain the close-neighbor vector (CNV), the distance matrix D and the initial value of nodes location was calculated. Theoretical analysis and simulation experimental results show that, the advance algorithm can realize the positioning of sensor nodes with good accuracy.

Abstract: Four kinds of porous structures, copper wire mesh, metal foam, copper fiber sintered felts and cross-connected micro-channel plates were applied in a heat exchanger. Heat transfer coefficient per unit volume, pressure drop and comprehensive heat transfer effect of the heat exchanger were studied. The results show that: four kinds of porous structures can enhance the heat transfer performance obviously. The heat exchanger with copper metal foam has the largest comprehensive heat transfer coefficient which can reach 821.5W•m-3•K-1•Pa-1. And it increased about 2.5 times than that of the heat exchanger without porous structures. The comprehensive heat transfer coefficient increases with the flow rate in small case and decreases with the flow rate in large case. The coefficient reaches the largest value at the flow rate range of 6L/h-8L/h. The heat transfer coefficient per unit volume of the heat exchanger with four kinds of structures increases with the flow rate, and the increasing trend tends slowly. Metal foam of brass has the largest heat transfer coefficient per unit volume of 1266.8 W•m-3•K-1. Pressure drop increases with the flow rate, and the increasing trend tends rapidly. The 200 mesh copper wire mesh has the least pressure drop of 968.8Pa.

Abstract: Mining classification rule of spare parts is very important for inventory management. In traditional classification work of spare parts, the attributes of spare parts were used as a standard to extract classification rules, but it was hard to know the influence of every attribute of spare parts, and which one should be considered, because the attributes of spare parts had many species. So it was necessary for inventory management to mine classification rules of spare parts. Because the values of many attributes of the spare parts are in form of the range of data, the grey rough set theory was borrowed to mine the classification rules in this paper. Firstly, the mining classification rules model of spare parts was built by the grey rough set theory. Then the attributes of spare parts were summarized, and the steps of mining data samples and the mining classification rules of spare parts were introduced respectively. Finally, case study from the classification management of the spare parts of a maintenance factory shows that the proposed mining classification rules model of spare parts based on grey rough set theory can reduce the unnecessary attributes of spare parts without affecting the results of classification.