No abstract

Compared with traditional guns, the cartridge belt of the Cased Telescope Ammunition (hereinafter referred to as CTA) is far away from the rifling when it is fired, which leads to a greater impact force in the process of extrusion, and further affects the barrel life and internal ballistic performance. A finite element model of the coupled projectile launching dynamics was established based on the elastic-plastic theory to study the mechanical characteristics of the extrusion process. The dynamic extrusion process of the conventional and CTA artillery projectile was simulated numerically, the corresponding data such as the extrusion velocity, extrusion resistance and the stress in the slope chamber were obtained, and the extrusion characteristics of the CTA artillery projectile were compared and analyzed. The results show that compared with the conventional artillery of the same caliber, the extrusion velocity and the extrusion resistance of the CTA guns are increased by 87.6% and 33.5%. The calculated results can provide a theoretical reference for the internal ballistics and structural design of the CTA guns.

Shirts belong to the traditional classic clothing, men's shirts to grasp the details is particularly important, sleeve is an important element of men's shirts, its structure and technological form determines the quality and style of shirts. A sewing machine actuator — automatic sleeve machine cloth flip mechanism are studied in this paper. Through the cooperation of pneumatic claw and stepping motor driving synchronous belt, the clamping mechanism completes the flip and overlay of large sleeve slit. By studying the realization mode of folding function, the motion of the clamping mechanism is analyzed, the turning path is designed, the transmission scheme of clamping and flipping is designed, the structure form of the mechanism is determined, the component parameters are calculated and selected, and the mechanism simulation is carried out.