Papers by Author: Zhuo Qiu Li

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Authors: Ying Wu, Ming Qing Sun, Zhuo Qiu Li
Abstract: Many efforts have been directed to the micro structure and performance evaluation of Electroplated Diamond Film. The indentation method has become extensively utilized in the evaluation of materials’ mechanical. Nano indentation devices, such as MTS-XP, are very useful, but on the other hand, are not affordable for many research institutions. This paper presents an effective and economic method for testing and evaluating micro-cracking performance of Electroplated Diamond Film on Instron 5848 MicroTester by considering the relative hardness values, and the need to evaluate the maximum strength for brittle materials in practical applications. The design of the test system, the evaluation methods, the test results, and the discussions are presented.
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Authors: Xi Fang, Si Rong Zhu, Zhuo Qiu Li, Yong Lv
Abstract: The interface properties of carbon fiber(CF) within the composite material has a great effect to its functional characteristics. The work is focused on the research of CF electro-mechanical response after its surface modification using acetone and nitric acid oxidation. With characterization by XPS and SEM, there exist the various changes on the CF surface not only the chemical elements or chemical groups. With changing CF’s resistance under uniaxial tension, the CF has differerent electro-mechanical response to loading force. Through statistical analysis, the research shows the sensibility of CF to the electro-mechanical effect can be improved by the surface modification with acetone process or nitric acid oxidization.
597
Authors: Si Rong Zhu, Liu Lin Kong, Zhuo Qiu Li, Yong Lv
Abstract: The paper aims to sense strains of structures in two-dimension stress states and to perform a large-region strain monitoring. Polymer-matrix Carbon Fiber Smart Stripes (CFSS) distributed in two ways are stuck on a bending plate to detect strains using the piezoresistivity of CFSS. Monotonous tests are conducted to calibrate the surface piezoresistivity of the CFSS and then cyclic tests are conducted to measure the strains of the structure using the constitutive relation of CFSS. Results show the experimental values by CFSS fairly good with those by gage factors.
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Authors: Zi Peng Chen, Ya Wen Dai, Peng Li, Zhuo Qiu Li
Abstract: According to IEC61000-4-2, the influence of ESD EMP on the wireless antenna is studied by the injection experiments and radiation experiments in this paper. The results of experiments show that the ESD EMP has significant influence on the wireless antenna, and various kinds of failures such as breakup, restart may be occurred. In order to solve this problem, a wireless protection program has been designed, in which the TVS diode was used as the first lever for protection and the π-type high pass filtering network as the second lever. This program not only has the traditional function of ESD protection, which can avoid the high voltage damage to the internal circuit, but also achieve the purpose of load matching, ensuring the signal source not distortion.
1928
Authors: Zi Peng Chen, Peng Li, Xi Fang, Zhuo Qiu Li
Abstract: The Electrical Resistance Tomography (ERT) is a new technology developed in recent years. Because of the characteristics as simple structure, low cost and non-invasive, the ERT has already application in geophysics, physical geography, mineral detection et al.in this paper, the ERT is used to detect the damage of the remote carbon fiber felt with wireless sensing technology. In experiment, the wireless technology is used to avoid the noise and the introduction of the long wires, which realized the remote detection; the Improved Newton -- Raphson algorithm is used to achieve the detective imaging, which had good results.
783
Authors: Ya Wen Dai, Zhuo Qiu Li, Xiao Yu Zhang, Si Rong Zhu
Abstract: With the emergence of large-size complex structures, conventional discrete sensors can’t meet the requirement of structure health monitoring because they can only sense the strain in a single direction. In this paper, based on sensing and covering properties of carbon fiber smart material (CFSM), an idea of a sensitive layer placed on the structure surface was proposed. By setting finite electrodes on the edge of the sensitive layer, the stress field of tested structure is transformed to electric field which is apt to be tested, and with resistivity tomography technology (ERT), field(global) monitoring on civil engineering structure can be realized. To avoid impact resulting from measuring errors caused by misc factors in experiment, CFSM ERT system was utilized in virtual experiments. Virtual Experiments were conducted on ANSYS finite element software aided by its excellent abilities in coupled field analysis. The virtual experiments included two cases: circular plate simply supported at its perimeter under single loading of different values in the center, and circular plate simply supported at its perimeter under multipoint loading in different positions. In the virtual experiments current incentive in adjacent electrodes and voltage measurement in other adjacent electrodes were implemented, and the measured voltage data was transmitted to the ERT system to obtain the contour plot of resistivity distribution. It indicates that for the single loaded CFSM virtual experiment with tensile strain, its resistivity is increased with the load increase. Compared with 1st and 2nd principal strain distribution in structure tested area, resistivity distribution will qualitatively reflect force field of structure. In multipoint loaded CFSM virtual experiment with compress strain, resistivity descends. Compared with 3rd and 2nd principal strain distribution in structure tested area, low resistivity area just locates at area of biggest strain. Based on virtual experiment, efficiency of CFSM ERT system is demonstrated, greatly supporting the consequent practical application.
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