Abstract. Based on the local annealing process with induction heating for the A286 alloy sleeve of the blind bolt, a mathematical model is built to analyze electromagnetic-thermal coupling. Influence factors, such as frequency and current, are investigated and analyzed using finite element method on temperature distribution and length of the annealing zone in induction heating. The experiment on local annealing of the sleeve is then carried out with the optimal parameters of annealing process. Results show that temperature distribution designed in annealing zone is in a good agreement with the hardness distribution of the sleeve. The local annealing process validated by wrinkle of the sleeve under axial compression is feasible.
In recent years, convolutional‐neural‐network based stereo matching methods have achieved significant gains compared to conventional methods in terms of both speed and accuracy. Current state‐of‐the‐art disparity estimation algorithms require many parameters and large amounts of computational resources and are not suited for applications on edge devices. In this paper, an end‐to‐end light‐weight network (LWNet) for fast stereo matching is proposed, which consists of an efficient backbone with multi‐scale feature fusion for feature extraction, a 3D U‐Net aggregation architecture for disparity computation, and color guidance in a 2D convolutional neural network (CNN) for disparity refinement. MobileNetV2 is adopted as an efficient backbone in feature extraction. The channel attention module is applied to improve the representational capacity of features and multi‐resolution information is adaptively incorporated into the cost volume via cross‐scale connections. Further, a left‐right consistency check and color guidance refinement are introduced and a robust disparity refinement network is designed with skip connections and dilated convolutions to capture global context information and improve disparity estimation accuracy with little computational cost and memory space. Extensive experiments on Scene Flow, KITTI 2015, and KITTI 2012 demonstrate that the proposed LWNet achieves competitive accuracy and speed when compared with state‐of‐the‐art stereo matching methods.
In order to discuss the heat transfer characteristics of the graphite welding pool and the copper electrode, in penetration brazing of Cu/Ni dissimilar metal wire. A mathematical model for electrothermal coupling, on penetration brazing of Cu/Ni dissimilar metal wire, is developed, to describe temperature distribution and influence factors of different types of graphite welding pool and copper electrode, using simulation and experimental tests. The simulation results show that temperatures of the common graphite welding pool is 749.88°C, while the experimental results show that temperatures of the common graphite welding pool is 752.23°C, and the corresponding temperature range of the copper electrode is 236.5°C to 752.23°C, respectively. Furthermore, the length of the copper electrode at high temperature is 16 mm. Since the common graphite has the lowest thermal conductivity, higher thermal resistance, at the contact interface, is developed, while the contact heat, transferred to electrode, is reduced. Last, the heat transfer effect of the common graphite is stronger than that of fine graphite, isostatic graphite and molded graphite.
Tool edge preparation can improve the tool life, as well as cutting performance and machined surface quality, meeting the requirements of high-speed and high-efficiency cutting. In general, prepared tool edges could be divided into symmetric or asymmetric edges. In the present study, the cemented carbide tools were initially edge prepared through drag finishing. The simulation model of the carbide cemented tool milling steel was established through Deform software. Effects of edge form factor, spindle speed, feed per tooth, axial, and radial cutting depth on the cutting force, the tool wear, the cutting temperature, and the surface quality were investigated through the orthogonal cutting simulation. The simulated cutting force results were compared to the results obtained from the orthogonal milling experiment through the dynamometer Kistler, which verified the simulation model correctness. The obtained results provided a basis for edge preparation effect along with high-speed and high effective cutting machining comprehension.
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