On February 4, 2022, at the opening ceremony of the Beijing 2022 Winter Olympic Games, the Olympic flame was lit in the center of the main torch "Big Snowflake". Subsequently, the torch platform located at the National Stadium (Olympic Central Area), beijing Yanqing Division, Hebei Zhangjiakou Division was lit in turn, and will continue to burn until the end of the Winter Olympic and Paralympic Winter Games, and will become permanent sculptures in the three places.
Night view of the torch platform of the Beijing 2022 Winter Olympics. Courtesy of the Academy of Fine Arts of Tsinghua University
96 pieces of "small snowflakes" form a "big snowflake", the olive branch is surrounded by a "silver ribbon", and the non-uniform two-way concentric rotation between the "big snowflake" and the "silver ribbon" ... The design of the torch stand became one of the highlights of the Winter Olympics. It is reported that the torch platforms in the three divisions were designed by Marseille, secretary of the party committee and professor of the Academy of Fine Arts of Tsinghua University.
Behind the flexible and flowing shape is the fusion of art and technology. "Not only is it an aesthetic work of art, but it's closer to a multidisciplinary interdisciplinary project." According to Marseille, the development process of the entire installation fully reflects the cross-integration of art, design, aesthetics and mechanical structure.
Structural stability is the biggest challenge
At the end of November 2020, receiving the design invitation of the team for the opening and closing ceremonies of the Winter Olympic Games, Marseille immediately organized teachers from the Department of Industrial Design and the Department of Sculpture, as well as more than 10 doctoral and master students to set up a design team.
Marseille told reporters that due to confidentiality requirements, director Zhang Yimou initially briefly introduced that the core element of the main torch passed by the International Olympic Committee is a circular sheet with a diameter of 10 meters, hoping that the academy team can give the core graphic more artistic beauty from the design perspective, and at the same time, under the premise of meeting the function and safety, to achieve more exquisite and complex movement of the core graphic.
In the original design of the program, it was more about "imagination". "If the core elements are not clear, other elements are difficult to identify and expand." On the way back, Marseille and the team members were repeatedly discussing, what is this "round sheet"? After many analyses and discussions, the team guessed that "the high probability is snowflakes". As a result, the team's later designs revolved around snowflakes.
Professor Marseille of Tsinghua Academy of Fine Arts led the team to simulate the support structure of the torch platform with a courier strapping tape. Courtesy of the Academy of Fine Arts of Tsinghua University
They picked up the discs in the studio to simulate this "round sheet" and used courier strapping to simulate the support structure. Marseille found that when the scale exceeds a certain proportion, it is not just an aesthetic problem, but an evolution into an engineering problem, the diameter of the 10 meters in the thin sheet in the air rotation, its own weight will make it bend, and only one fulcrum to land, "just like dancing ballet, all the weight of the human body falls on the tip of the toe, and the force on the tip of the foot is very large." ”
In addition, it is also necessary to meet the unfavorable climatic conditions such as severe cold and strong winds in the three places, so ensuring the strength and stability of support has become a major challenge. At the same time, the volume of these support structures cannot be too thick and too large, and they must complement the core elements in terms of shape, and cannot dominate the master, which increases the difficulty of design.
"Designing the torch stand is not only a matter of artistic modeling, but also structural, gas function, movement and other aspects that need to be considered, and when the volume exceeds a certain scale, it evolves into an engineering problem." Marseille said. Therefore, the team of the Academy of Fine Arts invited a team of professors from the Department of Mechanical Engineering and the Department of Civil Engineering of Tsinghua University to work together. After repeated discussions, taking into account factors such as wind load, snow pressure and self-weight, the above and lower two-point support method is proposed for the rotational motion support structure, and the leaves in the upper and lower olive branches are connected with the branches to form a double support structure, which effectively improves the strength of the olive branch support points.
"We asked teachers from the Department of Civil Engineering and the Department of Mechanical Engineering to test, considering factors such as materials, weight, thickness, etc., and using computers to simulate and measure the force of the torch stand under different winds." Under these data, we have strengthened the points. Marseille said.
In order to get close to the language of ice and snow, Marseille designed the support structure into a flowing and undulating "silver ribbon" form. "This is an abstract expression of the speed, passion, rhythm, jump and other characteristics of many events of the Winter Olympic Games." At the junction of the "silver ribbon" and the chassis, three support points were designed to ensure the stability of the structure; the team proposed the design scheme of "concentric two-way rotation", and interpreted the lighting effect and rotation effect through animation.
After drafting multiple models, Marseille selected 5 from them and submitted them to the director's group. In March 2021, the team learned that one of the most "reliable" solutions won the fierce competition.
During the construction of the torch stand. Courtesy of the Academy of Fine Arts of Tsinghua University
Use simulation experiments to determine how the small snowflakes are arranged
Looking closely at the torch stand, the large snowflakes are made up of 96 small snowflakes, each of which is inlaid with the name of a participating country. It is reported that the idea of composing small snowflakes and olive branches around each participating country into large snowflakes was put forward by director Zhang Yimou, so as to reflect the spirit of faster, higher, stronger and more united Olympics.
The team of Marseille professors at Tsinghua Academy of Fine Arts undertook the design of the torch platform in the three major competition areas of the Beijing 2022 Winter Olympics. Courtesy of the Academy of Fine Arts of Tsinghua University
Although this idea is certain, since the number of participating countries cannot be determined at first, how are the small snowflakes arranged? How is it connected to an olive branch? How to ensure the strength and reduce the wind resistance? These questions are extremely challenging.
Marseille told reporters that there must be some kind of structure between snowflakes and snowflakes to connect, and if this connection point is particularly conspicuous and not beautiful, "how can these small snowflakes be harmoniously arranged together?" We discussed it repeatedly. ”
The reporter learned from the Academy of Fine Arts of Tsinghua University that while the team deliberated on the olive branch art modeling, it also needed to consider the strength of its structure and the windward area, and proposed a number of more reasonable creative patterns in the structure through finite element analysis and topology optimization, and calculated and analyzed these patterns to obtain the possible materials, the weight of the entire torch and the reasonable distribution of the structure.
Finally, combined with a number of simulation experimental data, the Marseille team suggested that the shape of the small snowflakes be unified into a hexagonal shape, and the arrangement should adopt a honeycomb-like stable structure, so that no other external structure can be involved, and the small snowflakes can be tightly connected. Moreover, the shape of the small snowflake in the middle is exactly the shape of a snowflake.
"It not only realizes the perfect integration of artistic modeling and engineering structure, but also fully embodies the meaning of the close connection between various countries." Marseille said.
Hidden mechanical conveyor system below ground level
On the base table with a diameter of about 20 meters on the torch platform in the Olympic Central Area, there is a "silver ribbon" with a total height of about 11 meters and a large snowflake figure of an olive branch. However, this is only the part that can be seen above the ground.
To achieve the concentric two-way rotation of olive branch snowflakes and "silver ribbons", there is a complex mechanical transmission system under the ground. "One is clockwise, one is counterclockwise, and the two directions of rotation are staggered. There is a motor under the axis of the snowflake, and there is also a motor under the chassis where the ribbon is located, and the two sets of motors are independent. ”
In addition, the flare stand is to burn all the time and is transported by hydrogen fuel. "There is a control room at the far end, and there is a hydrogen pipeline under the ground that extends all the way under the flare table chassis to ensure that the torch can continue to burn. At the same time, it also leaves room for personnel to overhaul the equipment. ”
In terms of material selection, taking into account the public's perception of the ice and snow of the Winter Olympics and the fact that the main torch tower will be permanently retained in the three places, the team conducted a large number of material surface experiments on the color and texture closely related to the material senses, and finally selected stainless steel material and used 8K polishing process.
"Stainless steel materials have advantages in terms of strength, wind and rain corrosion resistance, and at the same time can make the crystal clear feeling of ice and snow that we want, and can map the surrounding scenery into it, stainless steel materials themselves are very heavy, but the polished mirror texture can produce a sense of weightless lightness in the light, which is a very suitable material." Marseille said.
At the opening ceremony of the 2008 Beijing Olympic Games, 2008 people sang and sang, and many people were impressed by this shocking scene. In that year, Marseille participated in the design of the opening and closing ceremonies of the Beijing Summer Olympic Games as a young teacher, and completed the design of performance props such as "Silk" and "Dragon Pillar" at the opening ceremony with the team.
After 14 years, Professor Marseille led the design team of the Academy of Fine Arts and the professors of the Department of Mechanical Engineering and the Department of Civil Engineering of Tsinghua University to complete the design of the outer torch platform of the Beijing 2022 Winter Olympics.
"Compared with 2008, the Beijing Winter Olympics also presented traditional Chinese elements, but more emphasis was placed on the interpretation of ice and snow sports themselves, reflecting the simplicity of science and technology, green environmental protection, this time participating in the Olympic Games design work, the mentality is relatively relaxed, and the understanding of the Olympic spirit is also deeper and more pure." Marseille said.
Beijing News reporter Feng Qi Editor Wu Hui Proofreader Fu Chunyan