Springback angle prediction of circular metal tube considering the interference of cross-sectional distortion in mandrel-less rotary draw bending

The springback directly affects the forming accuracy and quality of metal bent-tube, and accurate springback prediction is the key to the springback compensation and control. This paper investigates the springback of mandrel-less rotary draw bending (MLRDB) of circular metal tubes, and an innovative method, springback angle prediction considering the interference of cross-sectional distortion (IoCSD-SAP), is proposed. The digit decomposition condition variational auto-encoder generative adversarial network (D2CVAE-GAN) is developed to augment the data samples. Considering the nonlinear interference of the cross-sectional distortion on springback, auxiliary extended radial basis function (AE-RBF) is proposed. It establishes the mapping relationship between the characteristic parameters and cross-sectional distortion. By extracting the information encode of cross-sectional distortion as the condition input, this model realizes the condition prediction of springback angle. Taking MLRDB of 6060-T6 Al-alloy circular tube as a case study, the proposed method, IoCSD-SAP, is verified. According to the experimental results, the mean absolute percentage error (MAPE) for the springback angle of our proposed method is 4.73%, and three different analytical models are 38.92%, 14.39%, and 14.22%, respectively. It can be seen that our proposed method significantly improves the prediction accuracy of springback angle. For the springback angle prediction of circular metal tube in MLRDB, the data augmentation can effectively reduce the generalization error and improve the prediction accuracy. The nonlinear interference of the cross-sectional distortion on springback should be taken into account to improve the accuracy and robustness of the springback prediction model.

The effect of using the metal tube on laser welding of the battery case and the tab for lithium-ion battery

Given the drawbacks of the conventional welding methods in joining the battery case and tab in the lithium-ion battery, the laser welding technique using the metal tube has been introduced for the weld. The metal tube is supposed to contribute a positive effect on protecting the outside structure by blocking the injection of the spatters. However, the use of the metal tube is believed to affect the intensity as well as the power distribution of the laser gaussian beam. Through the observation and analysis in this study, both advantages and disadvantages of the application of the metal tube on the weld have been clarified. The use of the metal tube prevents the ejection of the spatter to the outside of the welding zone, the gap between the battery case and tab in the weld is also minimized. Besides, the limitation of the intensity and the power energy distribution of the laser Gaussian beam has caused significant changes in the morphology, mechanical, and electrical properties of the weld.

Study on the Composite Structure of Aluminum Foam-Filled Thin-Walled Metal Tube to Reduce the Charge Overload inside the Projectile during the Penetration Process

When a projectile penetrates a target at high speed, the charge loaded inside the projectile usually bears a high overload, which will consequently severely affect its performance. In order to reduce the overload of the charge during the penetration process, the structure of the projectile was improved by adding two buffers at both ends of the charge. In this study, the mathematical expressions were first gained about the axial buffering force generated by the thin-walled metal tube, aluminum foam, and the composite structure of aluminum foam-filled thin-walled metal tube when they were impacted by the high-speed mass block through reasonable assumptions and stress analysis. During the experiment on the high-speed projectile penetrating reinforced concrete target, the acceleration curve of the charge and the projectile body were obtained. The results show that the maximum overload that the charge was subjected to during the launch and penetration process was significantly reduced, and the change in overload, which the charge was subjected to during the penetration process, was also less obvious.

The Effect of Using a Metal Tube on Laser Welding of the Battery Case and the Tab for Lithium-Ion Battery

Given the drawbacks of the conventional welding methods in joining the battery case and tab in the lithium-ion battery, the laser welding technique using the metal tube has been introduced for the weld. The metal tube is supposed to contribute a positive effect including protection to the outside structure by blocking the injection of the spatters, and minimization of the contact gap between the battery case and table. However, the use of the metal tube is believed to cause the plume trapped inside and affect the intensity distribution of the laser gaussian beam. Through the observation and analysis in this study, both advantages and disadvantages of the application of the metal tube on the weld have been analyzed. The use of the metal tube prevents the ejection of the spatter to the outside of the welding zone, as well as minimize the air gap between the battery case and tab in the lap joint weld is also minimized. On the other hand, the trapped plume inside the metal tube and the reduction of the energy of the laser beam have been considered to cause significant changes in the morphology, mechanical, and electrical properties of the weld.