Qingdao, China
Qingdao, China

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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.


Sun X.Y.,CAS Shenyang Institute of Metal Research | Zhang B.,CAS Shenyang Institute of Metal Research | Lin H.Q.,CSR Qingdao Sifang Co. | Zhou Y.,CAS Shenyang Institute of Metal Research | And 4 more authors.
Corrosion Science | Year: 2013

The correlations between grain boundary precipitates (GBPs) area fraction and stress corrosion cracking (SCC) susceptibility for an Al-Zn-Mg alloy have been studied using TEM statistical investigations and image analysis. The results reveal that SCC susceptibility of the Al-Zn-Mg alloy first decreases and then increases with the increase of GBPs area fraction, which does not agree with Dix's anodic dissolution theory, suggesting that SCC of the Al-Zn-Mg alloy is dominated by hydrogen induced cracking when GBPs area fraction is relatively low and is dominated by anodic dissolution when GBPs area fraction is relatively high. © 2013 Elsevier Ltd.


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.


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.


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.


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

In arc welding of aluminum, a mixture gas, with argon, helium and N2,can improve the welding process. In comparison to the pure argon MIG welding, the arc is more concentrated and allows a higher application of energy, which increases the microstructure of weld bead. Welding thermal cycle curve of Ar-He-N2 gas shielding metal arc welding and argon metal arc welding are measured, which the peak temperature is higher, the cooling rate is faster than the former. A staining method is used for the microstructure analysis. In comparison to argon metal arc welding, the grain size is larger and porosity is lower in build up welding. In comparison to argon metal arc welding, the partially melted zone is narrower in butt welding. The results of experiment show that the characteristic of welding temperature field is the basic reason for promotion of welded joint mechanical properties. ©, 2015, Harbin Research Institute of Welding. All right reserved.


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

Traditional stress measurement method is time consuming and destructive. Based on the acoustic elasticity theory, ultrasonic stress measurement method is used to overcome these disadvantages. The ultrasonic stress measurement method has been proved its accuracy and reliability by actual measurement of a variety of industrial structure. During measurement, the experiment results in plastic region of welding residual stress field show more stable than that in elastic region, which can be called it "instability acoustic elasticity effect". To describe the mechanics of this phenomenon, special Gauss distribution of LCR enveloping peak acoustic elasticity fluctuation experiment was carried out. To reveal the mechanics of this phenomenon, series of analysis experiments were designed. Acoustic elasticity simulation test was done by the static stress field. Acoustic elasticity principal stress equation of elastic residual stress field was proposed, which can obtain the two principal stresses and the transverse residual stress by measurement result of longitudinal residual stress. ©, 2015, Harbin Research Institute of Welding. All right reserved.


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

For the demand of low heat input and high quality welding technology, the difference in multi-pass welding techniques for thick aluminum alloy plates with CMT welding and pulse MIG welding was investigated. The thermal cycles during welding were measured; the microstructure and mechanical properties (tensile, bending and microhardness) of the welded joint were analyzed. The tests show that comparing to pulse MIG welding, CMT welding technology could make weld with lower temperature field, decrease the softened zone, increase the impact toughness of the joint, and improve the weld microstructure significantly. The experimental results show that CMT welding can make better weld on thick aluminum alloy plate. ©, 2015, Harbin Research Institute of Welding. All right reserved.


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

For the demand of low heat input, high quality welding technology, the repair welding experiment using CMT welding technology have been examined in thick aluminum alloy plate welding. The multiple repair welding was performed for hot cracking test in thick aluminum alloy plate. The results have shown that the hot crack susceptibility of CMT welding is lower than the pulsed MIG welding process. The test showed that CMT welding temperature field was lower, and the microstructure of welding joint was improved significantly compared to the joint welded bypulse MIG welding. ©, 2015, Harbin Institute of Technology. All right reserved.


Shun X.,CSR Qingdao SiFang Co. | Wei C.,Qingdao University of Science and Technology
Proceedings of the 28th Chinese Control and Decision Conference, CCDC 2016 | Year: 2016

Regenerative braking is the most method frequently-used for EMU. It is the important project in the factory test of EMU. Due to the small capability of the power grid in the ring form test line, the great braking energy of regenerative braking act on the electric network can make the voltage of the electric network rapidly increased. which affects the safety of the EMU and the power network equipments. In order to ensure the safety running of EMU regenerative braking, We researched the electric energy absorption device for regenerative braking of EMU. The device adopts the design of transformer and multi-level power control based on high power bidirectional thyristor and middle voltage stainless steel resistance cabinet by air cooled. The design is not only reduces the cost of the equipment, improves the safety, facilitates the installation, but also greatly improves the reliability of the system. Several years of practical application show that if use the mature technology and the traditional devices of stability quality, We can get higher reliability and higher economic benefits. © 2016 IEEE.

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