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Qingdao, China

Liu X.L.,CSR Qingdao Sifang Co. | Jiang Z.W.,Yamaguchi University
Experimental Mechanics | Year: 2013

Piezoelectric wafer type actuator/sensor is widely used to generate and sense Lamb waves for Structural Health Monitoring (SHM). However, multiple Lamb waves modes are generally excited with this type of transducer. As a result, there is some difficulty in using Lamb waves for damage detection. To selectively generate a single A0/S0 Lamb mode, the tuned excitation of Lamb waves has been studied by some researchers. This paper investigates the design of the PZT actuator/sensor bonded to beam-like structure for generating single A0/S0 Lamb mode. In the study it is found that some factors, including the bonding layer, the unknown material properties and dynamical characteristics of the beam, will influence the design of PZT actuator/sensor. Piezoelectric impedance technique is introduced to facilitate the design of PZT actuator/sensor. Crack detection in beam using the tuned A0/S0 Lamb waves is performed. © 2012 Society for Experimental Mechanics. Source


Zhang C.,Shandong University | Zhao G.,Shandong University | Chen H.,Shandong University | Guan Y.,Shandong University | Kou F.,CSR Qingdao Sifang Co.
International Journal of Advanced Manufacturing Technology | Year: 2012

The most important way to improve the quality of aluminum profiles is to assure the material flow through die land exit with the same velocity. In this paper, a numerical model was developed to investigate metal flow behavior during aluminum profile extrusion. Firstly, the numerical model for a complex hollow aluminum profile was built based on the arbitrary Lagrangian-Eulerian program HyperXtrude. Then, with the numerical model, metal flow behavior at each stage during the whole extrusion process was analyzed and dead zones in the die cavity were also investigated by means of the particle tracking method. Finally, the numerical results were validated by comparing with the nose ends of two extrudates in practice, and the comparison showed that the numerical model developed in this work could provide the effective guidance for practical production. © 2011 Springer-Verlag London Limited. Source


Lu H.,CSR Qingdao Sifang Co.
Hanjie Xuebao/Transactions of the China Welding Institution | Year: 2015

Traditional stress measurement methods are time-consuming and destructive. Ultrasonic stress measurement method was used to overcome these disadvantages based on the acoustoelasticity theory. Ultrasonic stress measurement experimental equipment was established with Lcr waves. This method has proved its accuracy and reliability by actual measurement of such industrial structures as electric multiple units (EMU) and rockets. The entire envelope weighting algorithm was proposed to reduce the influencing factors for measurement accuracy, by which uncertainty of the system is lower than threshold method. ©, 2015, Hanjie Xuebao/Transactions of the China Welding Institution. All right reserved. Source


Feng Z.-P.,University of Science and Technology Beijing | Qin S.-F.,CSR Qingdao Sifang Co.
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2016

Planetary gearboxes are widely used in various types of machinery. Fault diagnosis of planetary gearboxes is very important. A method based on Hilbert vibration decomposition and higher order differential energy operator was proposed for planetary gearbox fault diagnosis. By adopting its advantages of low computational complexity and mono-component decomposition ability, Hilbert vibration decomposition was used to decompose a signal and meet the mono-component requirement for using the higher order differential energy operator. Considering its merits of fine time resolution and good adaptability to instantaneous changes of signals, the higher order differential energy operator was applied to detect the transient impulses induced by gear faults and to estimate the corresponding amplitude envelope and instantaneous frequency. Fourier transformation was applied in the higher order differential energy operator output and the obtained amplitude envelope and instantaneous frequency to identify the gear fault characteristic frequencies and thereby diagnose planetary gearbox faults. The effectiveness of the proposed method was validated with both simulated signals and test ones of a planetary gearbox. © 2016, Editorial Office of Journal of Vibration and Shock. All right reserved. Source


Zhang C.,Shandong University | Zhang C.,Huazhong University of Science and Technology | Zhao G.,Shandong University | Chen H.,Shandong University | And 2 more authors.
International Journal of Advanced Manufacturing Technology | Year: 2012

Taguchi's design of experiment and numerical simulation were applied in the optimization of an aluminum profile extrusion process. By means of HyperXtrude, the extrusion process was simulated and the effects of process parameters on the uniformity of metal flow and on the extrusion force were investigated with the signal to noise ratio and the analysis of variance. Through analysis, the optimum combination of process parameters for uniform flow velocity distribution was obtained, with the billet diameter of 170 mm, ram speed of 2.2 mm/s, die temperature of 465°C, billet preheated temperature of 480°C, and container temperature of 425°C. Compared with the initial process parameters, the velocity relative difference in the cross-section of extrudate was decreased from 2.81% to 1.39%. In the same way, the optimum process parameters for minimum required extrusion force were gained, with the billet diameter of 165 mm, ram speed of 0.4 mm/s, die temperature of 475°C, billet preheated temperature of 495°C, and container temperature of 445°C. A 24.7% decrease of required extrusion force with optimum process parameters was realized. Through the optimization analysis in this study, the extrusion performance has been greatly improved. Finally, the numerical results were validated by practical experiments, and the comparison showed that the optimization strategy developed in this work could provide the effective guidance for practical production. © 2011 Springer-Verlag. Source

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