Applied Mechanics and Materials Vols. 373-375

Abstract: The tested wheel loader machinery noise was 110dB and driver position was 108dB, more than Chinese earth-moving machinery standard. Engine noise is the main noise, so thirty-five test points were arranged around the cab and engine to analyze and find the main noise points. The frequency spectrogram show that the main frequency band for the engine and exterior cab are 120Hz and 216Hz, and the interior cab noise was caused by the vibration of the power train passed through the frame result in resonance. Analyzed and calculated the main frequency concludes that the main noise resources are engine exhaust noise and cooling fan noise. To decrease the noise, proper damping materials were affixed to the engine hood and interior cab, the metal pieces were tightened and the cooling fan and shock absorber were replaced with new ones that match the main noise frequency.

Abstract: Equipped with type AEM-RS electromagnetic current meter, the buoy provided effective technical platform for on-site rapid monitoring of the ocean current. Performance index and usage in the ocean current buoy of AEM-RS was introduced. Ultrasonic cleaning method in seawater was developed for preventing AEM-RS from biofouling. Ocean current data can serve for oceanographic research and marine resource exploitation.

Abstract: In order to solve data lack of underground water research and monitoring situation, a wide range underground water lever dynamic information monitoring network system was designed. Remote monitoring terminal based on the techniques of embedded and wireless transmission monitored the change of underground water level; Monitoring analysis center based on the JAVA technology of B/S architecture was designed to inquiry the real-time data,set parameter and analyze data, etc. An approximate water level point was obtained by adopting the modified small period prediction model and the weight distribution method. This enhances reliability of monitored data. By utilizing the technology of GPRS wireless data transmission and Ethernet technology, a remote and real-time data transmission channel was build. Large area application in Shanxi Province shows that the system has the stable performance and the reasonable structure. System can provide long-term reliable data for underground water research.

Abstract: This paper has designed a wireless sensor network (WSN) system which is suitable for the subway security environment. The system uses ZigBee wireless communication technology to form a network, uses the chip CC2530 as the core processor to design the hardware circuit for the network node, and the design of the embedded software is based on Z-Stack protocol stack. Through analyzing the factors having affection on the security environment, the system collects a variety of environmental information with some sensors, and completes the design of the sensor modules. The test results show that this system has the characteristics of low-power, low-cost and high reliability.

Abstract: In order to solve the problems of remote management on computer room for campus networks, OPC technology is introduced into the design of remote monitoring system for campus computer room. The application of OPC technology can improve the interoperability and adaptability among buses, and reduce the repetitive work of multi-bus system data in the process of the integration, so as to make computer room management more effective, and make the system update and integration become more convenient. Especially in the special environment, the application of OPC technology plays an instructive significance and reference value to unattended management and the remote fault diagnosis and maintenance.

Abstract: In this paper, wavelet packet transform and support vector machines are used to detect gear system faults. Testing signals were obtained by measuring the vibration signals of gear system at different rotating speed for different faults. Vibration feature signals were analyzed using wavelet de-noising. By using wavelet packet transform (WPT), signals were decomposed into different frequency bands. the fault detection is used for calculation of energy percents of every frequency. All these were used for fault recognition using Support vector machine (SVM). SVM and neural network transform results were compared. The research indicates that the de-noised signal is superior to the original one. When dealing with various signals, such as Multi-Faults, the diagnosis identification rates are over 92%. This method can be effectively used not only in engineering diagnosis of different faults of gear system, but also for other machinery fault style classification.

Abstract: Sea state conditions such as wind, wave and current vary in different ocean waters. Two similar offshore structures installed in two different ocean regions will yield different responses. Determining the transfer function of the structure is a system identification exercise that yields the structural response and behaviour given any sea state condition. The transfer function can be determined using available measured sea state data and structural response data. In this paper, a six-legged semisubmersible physical model is developed to a scale of 1:100 and is tested in a wave tank to measure its responses due to simulated random wave loads. The transfer functions of the semisubmersible model are then determined using the measured responses and the measured wave heights.

Abstract: By experiment,adopt clay as the transfer medium between copper bar and pavement,change the grounding mode of electrode,high density electrical method was used for subgrade failure detection. The experiment result show that this method can control all most ground resistance within 10KΩm and the subgrade failure can be detected. Because of the electrode grounding area is larger and the resistivity is higher,caused the inversion result has some error. This conclusion of experiment can provide reference for subgrade failure detection of high density electrical method for opening road.

Abstract: A new flatness error measurement method was proposed for large quantities of E-type AC relay, which was consisted of three discontinuous plane. The research object of this thesis is on both sides of the work piece plane. The relay was measured by utilizing multiple laser displacement sensors, and used the development of PC software to extract the measurement key points and process the collected data, which was used the method of least squares to calculate more accurate flatness error value. This method can achieve substandard work-piece fast sorting and rapid online measure.

Abstract: A new video image interpretation technology applied mainly to the angular distortion measuring system of navy vessel is developed in this paper. The video interpretation system incepts two video signals coming from two CCD of photoelectric self-collimation parallel optic equipment. Real-time video image processing and interpretation, as well as dynamic miss distance are achieved by using concurrent working mode, and the relatively distortion of vessel can be obtained by combining the two measurement results.