Applied Mechanics and Materials Vols. 687-691

Abstract: Compared to traditional manual-operation method for tunnel-wall deformation measurement, DCRP (Digital Close Range Photogrammetry) technique based on non-metric digital camera is a new emerging and more effective non-contact measurement method. In practical applications, the deformation parameter measurement jobs are throughout the entire process of the tunnel construction to ensure the safety of the project. There are urgent requirements for portability and miniaturization performances of the measurement system to reduce the interaction of measurement job and project construction. A configurable 3D control field equipment was presented, the control points of which could be freely configured according to the practical work conditions and do not need to be re-calibrated. A novel portable tunnel-wall deformation measurement system based on the non-metric digital camera and DLT algorithm was set up. Experimental results showed that the precision of the system for a large section tunnel-wall deformation measurement is better than 0.1‰. The system presented in the paper has the advantages of portability and miniaturization, as easy to implement fast and in-situ tunnel-wall deformation measurements.

Abstract: In this study, using simulated falls and activities of daily living (ADL) performed by elderly subjects, the ability to discriminate between falls and ADL was investigated with wearable tri-axial accelerometer sensors, mounted on the chest. The movement data of human body analysis was performed using one-class support vector machine (SVM) to determine the feature of motion types. Experiments to detect falls are performed in four directions: forward, backward, left, and right. The preliminary results show that this method can detect the falls effectively, reduces both false positives and false negatives, while improving fall detection accuracy, and the application can offer a new guarantee for the elderly health.

Abstract: Things of RFID-based asset management applications in the metering equipment, researching applicable to the marketing of RFID tags metering equipment, automatic identification metering equipment. Based on sensor network technology, a wireless sensor network are established in the metering equipment warehouse, working libraries and other areas so that each region and the metering device automatically perception, monitoring and recording the operation of process measuring device , strengthen out of storage management, metering equipment for the entire process of tracking. Innovative metering equipment on-site mode of operation, through handheld devices, allows the operator to automatically locate existing metering operation of equipment, a comprehensive record of on-site business information to improve business efficiency. System of things technology integration metering equipment monitoring information, will achieve metering equipment identity, authentication, monitoring, positioning and tracking, real-time monitoring metering device status, with warning alarm, query statistics functions.

Abstract: This work proposes an economical, practical, and easy-to-operate combined measuring device to measure volume. This device integrates measuring tools that are commonly employed in architectural engineering for gauging distance, height, area, and volume, and has an error rate of less than 1% in volume measuring. Regarding the microcomputer controller, the law of cosines in trigonometric functions was adopted to calculate side lengths. The experimental results verified that this device can identify the correlation coefficients of side-length measurements by using sensors and calculating the side length of an object according to the law of cosines .Consequently, the study device achieved non-contact volume measurement using a microcomputer controller, and the results conformed to the gauge repeatability and reproducibility (GR&R) method in measurement system analysis.

Abstract: This article considers a step-stress partially accelerated life tests for series system model where independent and non-identical Burr XII-distributed lifetimes are assumed for the components. Based on Type-I progressive hybrid censored and masked data, expectation maximum algorithm combined with auxiliary variables is developed for estimating the model parameters and the acceleration factor. In addition, the asymptotic confidence intervals are constructed by the parametric bootstrap method. Furthermore, the proposed method is illustrated through a simulation study under various masking levels.

Abstract: As for ultrasonic gas flow meters, special attention should be paid to transducer installation effect as the flow disturbed by transducers will greatly affect the transit time determination and accordingly reduce metering accuracy. This paper presents a numerical method to analyze the disturbed effects based on Computational Fluid Dynamic (CFD), which can give valuable guides for transducer installations. Different pipe configurations covering a wide velocity range are modelled to simulate the actual flow field in different chords for three transducer installations including protrusion, recess and half protrusion. Then, detailed results are presented and the mechanism is analyzed to give suggestions about better transducer installations and a modified weighting factor method to improve the incredible error is also given in this paper.

Abstract: Instantaneous speed signal is a new information source for diesel fault diagnosis. It has been used in critical fault diagnosis successfully such as misfire. But the occurrence rate of early weak diesel fault is high, and can’t be diagnosed easily by other information source, so it has high value to research on the weak fault feature extraction method of transient speed. Due to the difficulty in setting up effect and accurate mathematic model for diesel engine instantaneous speed under weak fault conditions, so in this paper the early fault simulated experiments are proceed in 6-135 type diesels. Many early faults are simulated by adjusting cylinder fuel eject quantity, adjusting exhaust valve clearance, simulating exhaust valve leak in differ degree. Through analyzing the variation rule of instantaneous speed signal in different status, the direct time domain fault feature is extracted. It is the instantaneous speed unitary rise amplitude ratio of every cylinder, the value of each cylinder is named as Pi. The experiments outcome shows that if Pi descend over 10%, then the No.i cylinder exist fault. The feature is very sensitive to some fault which influence gas press in cylinder such as fuel ejects quantity not uniformity and valve leaking.

Abstract: BP neural network has a good nonlinear mapping ability, and can describe the relationship between frequency characteristics and fault. However, the multi-resolution wavelet neural network has the simple learning rules, fast training speed with the avoidance of local minima. So a multi-resolution wavelet neural network based on UKF is proposed to solve the problem of fault diagnosis for rotating machinery. The simulation result shows that the proposed multi-resolution wavelet neural network based on UKF value has a good diagnosis capability, and is better than that of traditional BP neural network and wavelet neural network.

Abstract: This paper focuses on the detection technology for Electric Multiple Units (EMU) break valves features. Aiming at the issues of EMU break valves features detection, this paper propose a kind of EMU break valves feature detection technology based on neural network algorithm which does not overly dependent on break valve characteristic parameters. The spatial function neural network algorithm is used to predict the EMU break valves features. The experiments illustrate the proposed algorithm can increase the detection accuracy with satisfactory effects in EMU break valves features detection.

Abstract: Current OTS (Online Test System, OTS) of airborne electrical equipments in the environments of mechanics is only able to test statically but dynamically. To solve the problem, a new kind of dynamic test system based on PXI bus is designed. In the design, modular instrument resources that used in the third generation of ATE (Auto Test System, ATE) commonly is adopted to prove the system’s reusability, extensibility and standard ability, digital signal acquisition is replaced with analog signal acquisition to realize dynamic test, support from the method of process monitoring is drew to get the capability to detect the reversible failure in UUT (Unit Under Test, UTT), VC++ language is used as the software development tool to control the system and record test data. In the special mechanics environment such as centrifuge, drawing lessons from the experience of the new concept dynamic test, the system architecture of remote control acquisition is used to prove the stability and efficiency of the test system greatly. The experimental result shows that the system runs well and has more advantages such as high efficiency of auto-test and reliability of failure diagnosis results, meeting new demand of the airborne electrical equipments’ online test in the environments of mechanics.