Applied Mechanics and Materials Vols. 105-107

Abstract: The speed and position measurement is an important part of the train control system. Accurate measurement of train speed and position ensures safety of train running and improves transportation efficiency. Traditional methods to measure speed and position usually rely on single sensor, which has less accuracy and reliability. A method of measuring train speed and position based on multi-sensor fusion is proposed in this paper. Since trains are running on fixed rail tracks, the position of train can be determined by the traveled distance and speed monitoring is essentially to measure the magnitude of train velocity. According to this characteristic, this measurement system consists of axle odometer, Doppler radar, accelerometer and intermittent inquiry balise. The federated Kalman filter is used to implement multi-sensor fusion. Simulation experiment results prove that this method can improve the accuracy and reliability of train speed and position measurement.

Abstract: The energy flow of equal inclination interference fringes in Michelson interference measurement is theoretically calculated, and its variation with the optical path difference is also analyzed. When the ratio order of interference radius to focal length of the lens is as low as 10-2 or lower, the energy flow variation with the optical path difference is sinusoidal with period λ/2. Simulation is made via Matlab to verify the theoretical calculation and good agreement has been obtained between theoretical analysis and simulation. The parameters to be measured can be achieved via the record of the change in stripe energy flow, which is superior to the conventional method recording variation in stripe light intensity in good stability and strong anti-jam.

Abstract: For shaft angular acceleration is the key to rotary system state inspection and fault analysis, two new angular acceleration sensors based on the principle of electromagnetic induction are presented. When the angular acceleration component exist in rotary system, this component is output in the form of induced potential through electromagnetic coupling. The output voltage of sensor can reflect the changes of mechanical angular acceleration according to the experiment. The errors of sensor on actual working condition are analysed, and a new calibration method of sensor is presented, which affords technical support for the popularization and application of sensor.

Abstract: In order to accomplish the Prognostics and Health Management System(PHM) for guided missile, sensor network node of storage and conveyance’s environment’s monitoring based on multi-MEMS sensors is designed. Centering on the low power consumption singlechip, microsensor collecting the information of temperature, humidity, acceleration(calculate quiver), and magnetic field intensity(calculate posture), realizing the wireless communication between the node and the upper management system (ARM controller) with the radio frequency send-receive chip nRF2401. This node has the characteristic of small volume, easy to layout, low power consumption, continuous operation for long time and so on. It preferably realized the function of information terminal of PHM system.

Abstract: Automobile body sheets mainly resist impact and pressure. However, the fatigue property is one of the main factors with regard to properties of sheet steels. Continuous vibration happens all over the sheet steels (especially chassis) while the vehicle is in motion. And the fatigue property becomes particularly important in the condition above. Fatigue tests are conducted to four kinds of thin sheet steels for automobile in this paper. The fatigue lives of samples from sheet steels are obtained according to the various stresses. The inferior limits of fatigue life and the inferior limits of fatigue strength under the higher stresses are acquired by the computation of fatigue data. Furthermore, the test results show that there is a certain relationship among the tensile strength, yielding strength and inferior limit of fatigue strength for these sheet steels. This paper is of certain reference significance for other similar test.

Abstract: Corona discharge is a kind of self-sustained discharge that emerges in daily life, industrial production and other fields. A variety of works have been done on this issue. And corona discharge in high-velocity airflow is of great significant especially. In this paper, an experimental system is proposed and assembled, to research the characteristics of corona discharge in high-velocity airflow and the differences between corona discharge with and without high-velocity airflow. By comparing simulation results of velocity field and pressure field of air amplifier and Laval nozzle, proper airflow supply device is selected. The experiment cabin is designed following the requirements of corona discharge to airflow by mathematical calculation. We also design the discharge device and receiving device by theoretical analyses. Experiments of corona discharge with and without high-velocity airflow are both done in the system. Significant distinctions showing the impact on corona discharge of high-velocity airflow is observed.

Abstract: The purpose of a time discriminator is to decide when the input is something you are interested in. It does this by putting out a logic pulse when the input signal meets an adjustable threshold value. A low cost high performance constant fraction discriminator (CFD) for laser rangefinder using pulsed TOF (time of flight) is proposed with the accuracy been improved. The theory of CFD is deduced and discussed and a distance measuring system has been established and experimental evidence is presented to show the feasibility of solving the time walking error problem to amend the precision and improving the environmental applicability, the distance error of +/-0.5mm was observed in the lab condition. The advantages of this instrument are highlighted and the experimental results are presented.

Abstract: Many of the NDT methods used for casing, tubing, drill pipe and line pipe are applicable, with some minor modifications, to CT. This article describes the requirements of an ideal in-service inspection. This paper presents a new wall thickness and ovality measuring method engineered for reliable field use. This method based on flux gate testing technology discussed in this paper .This method not only will detect internal flaws and the density of micro-cracks, but also wall thickness measurements will be made. This paper discusses the development of this new method, the detection of eddy current testing program is used in coiled tubing ovality measurements. The key technology is the production of amorphous alloy core. Using this method measure diameter, wall thickness and ovality of CT, is currently being developed.

Abstract: A wireless data acquisition system based on MSP430F149 is developed for the measurement of microbial fuel cells’ voltage. The main function of this system is to convert the analog input voltage into digital output code, process the digital code, and transfer the data through the GSM network or the USB interface. The core of the data acquisition device is a 16-bit general purpose Texas Instruments ultralow-power microcontroller MSP430F149. As the voltage of a microbial fuel cell is very low, the A/D converter circuit is specifically designed for high precision and high accuracy. A real-time clock is used to achieve timing measurement and the time interval can be set to meet demands. The data collected is transferred through the GSM network. Besides, a Windows environment application developed with Visual C++ can be used to access the data stored in the flash memory through USB interface.

Abstract: It is a challenging problem to test the acceleration of the high-speed missiles and space shuttle under high temperature. This paper proposed a design of LC-resonant and high-temperature resistant acceleration sensors about the phenomenon. With the operational amplifier OP4177, it produces the input signal that contents with A/D (Analog to Digital) signal. An eight level low-pass filter MAX291 is used for testing after the signal is regulated. This design mainly uses AD7934 to complete the conversion from analog signals to digital signals. It also recognizes the resonant point of LC acceleration sensor by the DSP （Digital Signal Processing）recognizing program. The acceleration is computed finally by the DSP chip.