Applied Mechanics and Materials Vols. 157-158

Abstract: Excitation signal optimization is an important part in the power system identification based on ambient signals. An adaptive discrete Kalman filter method is proposed to select an optimal signal for closed-loop identification in this paper. This method is carried out through the use of the measurement innovation sequence as piecewise stationary process inside an estimation window. It also overcomes the shortcomings of relying on the correctness of the mathematical and statistical models excessively. The feature of random load changing in power system is fully considered in this method. Then under the energy constraints of input and output signals, this method can be used to solve the excitation signal which satisfies the performance of power system and the noise covariance estimation matrices are acquired. By using this method, the optimal identification model can be obtained. Simulation results show the effective performance of the proposed method. Compared with other methods, the quality of the closed-loop identification model based on ambient signals is improved by using the excitation signal optimal method proposed in this paper.

Abstract: High temperature pin-on-disk tester heated by middle frequency induction was designed. Friction test of hot work die steels with the same composition treated under three different heat treatment conditions was carried out by the pin-on-disk tester at high temperature. The experimental temperature were 200°C、300°C、400°C、500°C, applied loads were 1kg、1.5kg、2kg、2.5kg, respectively, pin-on-disk circumrotating speed was 1000r/min for all the experiments. Morphology of worn surface and sub-surface structure were observed by optical microscope. Experimental results indicat that wear loss decrease with temperature increasing. Meanwhile, there are various growing rule under different loads, wear loss increase slightly under low load, but increase rapidly with load increasing, especially increment become larger at low temperature. Morphology of worn surface show that the two-body abrasive wear are mainly mechanism under low temperature and low load condition, oxidation wear and adherence abrasive wear are mainly mechanism under high temperature and high load condition.

Abstract: The analysis of spindle static stiffness is particularly important. The concept of spindle stiffness is introduced. Based on software ANSYS, the finite element analysis model of simplified spindle is established. Two equivalent forms of bearings are discussed and the analysis results are compared. The stress distribution nephogram of spindle is given. The research indicates that using spring-damper element instead of bearings is more suitable and the machining accuracy mainly depends on the stiffness rather than strength.

Abstract: 3D visualization simulation is the important research method of port logistic production system, whereas the lack of uniform standard and interface of 3D simulation model, it is very difficult to share the simulation model resource, and which caused modeling repeatedly and developing efficiency lowly. Container terminal 3D simulation model repository should be considered as the key factor of solving the problems of developing low-efficiency and model no reuse of logistic system. This paper classified the model resources required by container terminal 3D simulation, explained the functions of container terminal 3D simulation model repository, and gave its framework. Finally, we discussed the key techniques to implement the container terminal 3D simulation model repository.

Abstract: There are many problems in the off-line manual press mounting of tapered roller bearing outer ring of some automobile gearbox shell, which are unstable quality, poor precision, the low efficiency and high labor intensity. In order to solve these problems, we designed a vertical pile press machine. PLC is used to achieve automatic control production, and the stable mounting force provided by air pressure system can adapt to the press mounting requirements of the bearings of eight and nine shift gearbox shell. On being applied to the automatic production line, it can press-mount simultaneously the outer ring of intermediate shaft bearing and the second shaft bearing, and switch rapidly between the eight shift gearbox and the nine shift gearbox. Therefore the automatic production is achieved , which improvs the production efficiency , ensures the assembly quality, and brings higher profit to the enterprise.

Abstract: Chinese fir and eucalyptus are the important plantation wood species in China. Wood color is a property that can reflect aesthetic features of wood and increase the perceived quality of wood. The color parameters of the two woods and the ability of near infrared (NIR) spectroscopy to assess the color parameters were investigated in this study. The results shown the L*, a* and b* values of Chinese fir were 51.91~73.33, 6.26~12.94 and 20.36~32.04 and that of eucalyptus were 42.30~62.44, 8.48~62.44 and 15.07~25.15 respectively. The excellent related coefficients (r) and lower square error of calibration (SEC) illustrated NIR spectroscopy coupled with multivariate data analysis has ability to rapidly predict the L*, a* and b* values of the two wood species. The use of reduced spectral range has little effect on the quality of PLS models allowing the use of inexpensive and portable spectrometers with lower wavelength region to rapidly assess wood surface color.

Abstract: In this paper, a novel MEMS inertial switch is designed and characterized for the purpose of crash sensing for ammunition systems in which high-speed response is required for triggering the detonator. In order to keep the same sensitivity in different direction, the structure of an annular proof-mass suspended by four serpentine flexures is designed. The switch can be integrated with electronics, fast-acting，and lack of a requirement for continuous power, and can be used in a wide area. The motion of the inertial switch is analyzed by dynamic simulation under the 700g threshold acceleration in y direction, the simulation results show that the response time is 0.142ms and the contact time of the switch is about 5 , it illustrates that the response time is short enough and the impact time satisfy the ask. The von-mises stress of the structure is calculate, the maximum stress occurs in the serpentine flexures, the value is 60.61 MPa, much less than the yield strength of the silicon, the switch can be used time after time.

Abstract: Undertake the study of the topic home monitoring system, the wisdom of building the health care environment monitoring and automation control systems, sensor signal is transmitted through ZigBee wireless technology and NI data acquisition card to do transfer cable transmission technology. In addition, an infrared remote control technology for automation and control for air conditioning. Improvements in the system developed sensors were temperature, humidity, carbon monoxide, illumination, and sensor signal transmission through wireless technology and cable transmission technology, to the terminal for processing, record, query and other features, then the terminal through RS -232 assigned for IR control module control packets, and output through PPM IR code to the IR receiver, and thus control of indoor air conditioning.

Abstract: The study of water coning phenomenon has gained wide interest in petroleum industry during the last few decades and poses a challenge for hydrocarbon production. The simultaneous production of water and oil causes lots of negative effects on the reservoir performance such as significant reduction in oil recovery, corrosion, the cost of oil and water separation, environmental pollutions, and etc. Hence investigation of water coning and finding some solutions seems highly noticeable. For that, we model one of the Norwegian reservoirs which encounters water coning problem by using a black oil simulator. Additionally, since it is not well-matched with its observation data, by the use of SimOpt software, a reasonable match between the simulated and observed data were achieved. After achieving a reasonable match between the observed and simulated data in SimOpt, by the use of ECLIPSE 100 software various scenarios are investigated. Controlling the oil production rate, controlling the field water cut, and the effect of different well completions are different factors whose influences over the water coning phenomenon are examined. Finally, the following solutions are suggested: the varied production rate, field water cut in the range of 0.1 to 0.2, and the open-hole completion.

Abstract: The workflow of mean shift has been put forward which is aimed at the intelligent vehicles. To select the logical parameter, the simulation of the formwork and the selection of search region is made; and select the most suitable algorithm of the three related algorithms through the simulation analysis; in addition, to achieve the binary image by difference and denoising, to obtain the energy distribution of the image by calculating the gravity centre of the projection, then proceed to the next step, to gain the target location. So the feasibility of the algorithm can be validated by the test, and the good results are obtained.