Professor Sun Yize held an academic exchange meeting for the team. Courtesy of Professor Sun Yize's team
February 2(Zhu Yichao, Xu Jing) The opening of the 2022 Beijing Winter Olympics is imminent, and the torch relay ceremony is underway. As one of the elements that have attracted much attention in previous Olympic Games, the "flying" of the Winter Olympic torch has attracted countless attention as soon as it is unveiled. As the key manufacturing technology provider of the outer streamer (shell) of an important part of the torch, the team of Sun Yize of Donghua University unveiled the "big" knowledge behind the "small" torch.
Recently, the reporter walked into the office of Sun Yize, a professor at the School of Mechanical Engineering of Donghua University and director of the Textile Science and Technology Innovation Center, which was still a hot scene, and he was conducting academic discussions with the members of the research group.
The outer streamer shape of the torch "Flying" is very special, it is a high-dimensional surface body, which is an extremely complex heterosexual structural part for engineering manufacturing. What is the black technology behind the little torch? "This is a perfect collision of art design and technological innovation." Sun Yize summarized the three "high" words of "high-tech materials", "high-tech equipment" and "high-end manufacturing".
In August and September 2020, Shanghai Petrochemical, the overall bearer of the torch, found Sun Yize, who has been working in the field of automatic weaving equipment for nearly 20 years, and threw out a difficult problem - how to use carbon fiber composite materials to present the imaginative outer torch ribbon art modeling with high precision.
Sun Yize explained that the first thing he saw was a clay torch work "Flying", which is inspired by the artist, hand-shaped boutique, to complete digital manufacturing, industrial production, and with high-tech carbon fiber composite materials woven and formed, the first difficulty to break through is mathematical modeling, only mathematical modeling can restore and reproduce beautiful art design works with high precision, making automated digital manufacturing possible.
The world's largest three-dimensional spherical three-dimensional weaving machine has been developed. Courtesy of Professor Sun Yize's team
In order to lay a good "foundation", Sun Yize led the team to the north several times, and repeatedly discussed, revised and polished with the torch shape designer team of the Central Academy of Fine Arts and the relevant staff of the Winter Olympic Organizing Committee. During the Spring Festival last year, the members of the research group were still working intensively to test and change the plan, from busy day to night. "The PhDs on the team dreamed several times at night that they were doing mathematical modeling of the outer streamers of the torch."
In the production workshop of the cooperative team Huai'an, a ring -- 8-meter-diameter "big guy" is running at high speed, with hundreds of black silk tows interweaving and shuttling, which at first glance looks like "knitting sweaters", and it only takes a few minutes to "weave" a torch coat that is accurate to grams.
Sun Yize said that the outer streamer of the torch is flexible and beautiful, but because it is variable diameter, curvature, up and down is not generally thick, the thickness of the curved surface is not consistent, the traditional manufacturing process can not be realized, and the "big guy" in front of him is the "secret weapon" of "weaving" the torch coat, developed exclusively by Donghua University, the world's first large-size heterosexual structural parts three-dimensional high-precision spherical three-dimensional knitting machine, the series of knitting machines can weave large aircraft, high-speed rail and other large-size structural bearing parts, but also weave propellers, drones, Precision special-shaped structural parts such as flare outer streamers.
This "big guy" has a total of 576 weaving spindles, which can weave a maximum cross-section of 500 * 500 mm, which is currently the world's most powerful and largest three-dimensional spherical three-dimensional knitting machine. When the equipment is working, in the circular spherical track, 576 high-speed moving spindles constantly change tracks and cross and shuttle at a rapid speed.
Team members are on site to guide the three-dimensional weaving. Courtesy of Professor Sun Yize's team
"This weaving process can be said to be 'dangerous', each movement spindle has 14 kinds of collision possibilities at every moment," Sun Yize made an analogy: "It's like on a four-lane highway, there are hundreds or even thousands of cars quickly crossing and shuttling through, not only high-speed running, but also constantly crossing, inside and outside penetrating lane change running, we can avoid 'traffic accidents' through intelligent calculation and precise track change control."
In order to make these carbon fiber composite materials "obedient" in the weaving process, and at the same time in the industrial production of three-dimensional reduction of the soft and flowing feeling of the outer streamer, Sun Yize led the team to study the control algorithm, wonderful mechanism, track change technology, etc., from theoretical derivation to experimental verification to production practice, repeated debugging. Invented the so-called "eccentric" weaving method, solved the problem of large curvature and variable density weaving; original double robot collaborative clamping mandrel control algorithm to ensure the optimal dynamic performance of large-size special-shaped structural parts weaving under complex stress state; developed a single yarn tension whole process digital control technology to achieve constant tension precision weaving; developed a high-dimensional surface automatic grinding skill operation robot system. Realizing the three-dimensional automatic three-dimensional weaving and automated grinding of the outer streamer belt of the torch, the project technology not only fills the domestic gap, but also takes a leading position in the world.
In the end, Professor Sun Yize's team made the torch "alive" and truly showed the best "flying" state.
"Small torches carry large energy, and we in China have the ability and technology to weave and form high-precision carbon fiber composite materials!" Looking at the picture of the successful passing of the torch on the TV, Sun Yize said excitedly. (End)