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Texture Representation and Application of Colored Spun Fabric Using Uniform Three-Structure Descriptor

Li Yuan, Muli Liu, Liu JunPing, Yang Yali, Gong Xue

Autex Research Journal

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2022

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Vol. 22, no. 4

477--487

EN

The local binary pattern (LBP) and its variants have shown their effectiveness in texture images representation. However, most of these LBP methods only focus on the histogram of LBP patterns, ignoring the spatial contextual information among them. In this paper, a uniform three-structure descriptor method was proposed by using three different encoding methods so as to obtain the local spatial contextual information for characterizing the nonuniform texture on the surface of colored spun fabrics. The testing results of 180 samples with 18 different color schemes indicate that the established texture representation model can accurately express the nonuniform texture structure of colored spun fabrics. In addition, the overall correlation index between texture features and sample parameters is 0.027 and 0.024, respectively. When compared with the LBP and its variants, the proposed method obtains a higher representational ability, and simultaneously owns a shorter time complexity. At the same time, the algorithm proposed in this paper enjoys ideal effectiveness and universality for fabric image retrieval. The mean Average Precision (mAP) of the first group of samples is 86.2%; in the second group of samples, the mAP of the sample with low twist coefficient is 89.6%, while the mAP of the sample with high twist coefficient is 88.5%.

2

Enhancing the Strength of Al/Mg Dissimilar Friction Stir Lap Welded Joint by Zn Filler Addition Combined with an Appropriate Heat Input

Zhao Huaxia, Gong Peng, Ji Shude, Gong Xue

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 1

137--146

EN

7075-T6 Al and AZ31B Mg dissimilar alloys were friction stir lap welded with or without a Zn filler, and the effect of heat input on the joint quality was systematically studied. The experimental and finite element simulation results displayed that the formation characteristics and microstructures of the joint with or without the Zn filler were significantly affected by the heat input. The tensile shear load of joint with or without the Zn filler increased first and then decreased with the decrease of the welding speed from 200 to 50 mm/min. Moreover, the peak temperature in the stir zone was significantly decreased by the Zn filler addition, and the high temperature zone narrowed along the plate thickness direction. These changes of heat input made that longer mixing region boundary length and larger effective lap width were attained as the Zn filler was used. In addition, due to the replacement of Al-Mg intermetallic compounds (IMCs) by Al-Mg-Zn and Mg-Zn IMCs which were less harmful to the joint, the tensile shear load of the joint with the Zn filler was obviously enhanced compared to that of the joint without the Zn filler at each welding speed. The maximum tensile shear load of 7.2 kN was obtained at the welding speed of 100 mm/min.

3

Ultrasonic Assisted Active-Passive Filling Friction Stir Repairing to Eliminate Volume Defects

Wang Tao, Gong Xue, Ji Shude, Xue Gang, Lv Zan

Archives of Metallurgy and Materials

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2021

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Vol. 66, iss. 1

217--222

EN

Ultrasonic assisted active-passive filling friction stir repairing (A-PFFSR) was proposed to repair volume defects in the metallic parts. Sound joints without interfacial defects could be achieved. Firstly, the ultrasonic was beneficial to improving material flow and atom diffusion, and then eliminated kissing bond defects compared to conventional A-PFFSR joints. Secondly, the equiaxed grains were refined by ultrasonic vibration. Lastly, the repairing passes were reduced due to the ultrasonic, which decreased softening degree of the repaired joints. The maximum tensile strength of 150 MPa was achieved. Therefore, this strategy to repair the volume defects is feasibility and potential in the remanufacturing fields of aerospace and transportation.