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In this study, the correlation between welding quality and features of acoustic emission (AE) signals collected during laser microwelding of stainless-steel sheets was analyzed. The performance of selected AE features for detecting low joint bonding strength was tested using a developed monitoring system. To obtain the AE signal for analysis and develop the monitoring system, lap welding experiments were conducted on a laser microwelding platform with an attached AE sensor. A gap between the two layers of stainless-steel sheets was simulated using clamp force, a pressing bar, and a thin piece of paper. After the collection of raw signals from the AE sensor, the correlations of welding quality with the time and frequency domain features of the AE signals were analyzed by segmenting the signals into ten 1 ms intervals. After selection of appropriate AE signal features based on a scatter index, a hidden Markov model (HMM) classifier was employed to evaluate the performance of the selected features. Three AE signal features, namely the root mean square (RMS) of the AE signal, gradient of the first 1 ms of AE signals, and 300 kHz frequency feature, were closely related to the quality variation caused by the gap between the two layers of stainless-steel sheets. Classification accuracy of 100% was obtained using the HMM classifier with the gradient of the signal from the first 1 ms interval and with the combination of the 300 kHz frequency domain signal and the RMS of the signal from the first 1 ms interval.
Ming-Chyuan Lu; Shean-Juinn Chiou; Bo-Si Kuo; Ming-Zong Chen. Analysis of Acoustic Emission (AE) Signals for Quality Monitoring of Laser Lap Microwelding. Applied Sciences 2021, 11, 7045 .
AMA StyleMing-Chyuan Lu, Shean-Juinn Chiou, Bo-Si Kuo, Ming-Zong Chen. Analysis of Acoustic Emission (AE) Signals for Quality Monitoring of Laser Lap Microwelding. Applied Sciences. 2021; 11 (15):7045.
Chicago/Turabian StyleMing-Chyuan Lu; Shean-Juinn Chiou; Bo-Si Kuo; Ming-Zong Chen. 2021. "Analysis of Acoustic Emission (AE) Signals for Quality Monitoring of Laser Lap Microwelding." Applied Sciences 11, no. 15: 7045.
The relative spatial position of each chain link and the phase angle of engaged tooth are not concerned in traditional sprocket designs. As such, the chain shifting might fail regularly. In this study, an optimized path of one chain for up-shifting is derived. Such path is formed by several bended chain links sustain yaw and roll. Empirically, appropriate bending, yaw and torsion angles for tooth chamfer, could be shorten the up-shifting distance and phase angle required, eventually facilitate not only more ascending points compactly arranged on sprocket but larger chain laterodeviation which curtails sprockets clearance and integrates the sprocket unit. Then again, the optimized shifting path promotes efficiency and decreases required movement yielded by derailleur tappet pressure.
Y.-Z. Ma; S.-J. Chiou. An Optimal Model on Contour of Up-Shifting Tooth for Derailleur System of Bicycle. Journal of Mechanics 2016, 33, 759 -767.
AMA StyleY.-Z. Ma, S.-J. Chiou. An Optimal Model on Contour of Up-Shifting Tooth for Derailleur System of Bicycle. Journal of Mechanics. 2016; 33 (6):759-767.
Chicago/Turabian StyleY.-Z. Ma; S.-J. Chiou. 2016. "An Optimal Model on Contour of Up-Shifting Tooth for Derailleur System of Bicycle." Journal of Mechanics 33, no. 6: 759-767.