China's new generation of fluid high-pressure forming technology overcomes the international problem of coexistence of wrinkling and cracking defects in the formation of ultra-large and ultra-thin curved surfaces. It breaks the foreign technical blockade and directly forms the thin wall of a 3m-class fuel tank for the first time in the world At the bottom of the overall box, he successfully won the "crown" on the rocket.
According to reports, the bottom of the fuel tank is known as the "crown" on the rocket. Because the fuel storage tank is the main structure of the launch vehicle, it is composed of a barrel, a fork ring and the bottom of the tank. However, the bottom of the tank is subject to complex forces and is a key component that affects the reliability of the full arrow. NASA and ESA of the United States use the "thick plate (more than 50mm) + hot-spinning blank + NC milling" technology line to manufacture the overall structure of the box bottom, but this method has complex processes, long manufacturing cycles (about 6 months), materials Waste is serious (90% of the material is milled), and large spinning equipment in the United States and Europe currently imposes an embargo on China. Therefore, the "bottom forming + welding" structure is commonly used in the bottom of the tanks of active rockets in China, but this structure has poor dimensional accuracy, high reject rate and low reliability, which has become a bottleneck problem restricting the development of launch vehicles.
The "New Technology for High Pressure Forming of Bidirectional Controllable Pressurized Fluid" proposed by Professor Yuan Shijian's team at Harbin Institute of Technology solved the problem of coexistence of wrinkling and rupture of deep cavity curved parts, breaking the forming limit of the existing technology. This technology subverts the technical routes that the United States NASA and ESA have followed for decades, and breaks down the developed countries' blockade and equipment embargo on China ’s overall rocket box bottom manufacturing technology.
"We use a thin plate with the same thickness as the component to directly shape the thin-walled overall bottom of the 3m fuel tank of the carrier rocket. This is also the first time in the world." Said Liu Wei, an associate professor at Harbin Institute of Technology. The block welding structure completely eliminates welding seams, and its comprehensive mechanical properties are superior to traditional welding structures, which can greatly improve the reliability of the launch vehicle.
In order to realize the industrial application of this technology, the Institute of Fluid High-Pressure Forming Technology of Harbin Institute of Technology, in conjunction with aerospace and other departments, independently developed a super-high-pressure sheet fluid high-pressure forming machine. This sheet fluid high-pressure forming machine is currently the world's largest thin-plate hydroforming machine. The forming force and high-pressure liquid volume are 1.5 times and 10 times the previous largest similar equipment abroad. The team used multi-channel supercharger parallel synchronous control technology to solve the problem of super large-volume high-pressure liquid pressurization and regulation.