What? Fashionable socialites can actually "participate" in rocket building!

As you can imagine from the title, this is a story that spans a long period of time - the time span is also the same, from the late 19th century to the middle of the 20th century.

The story begins with a bold woman named Madeline Vionnet. Male readers may not know who she is, but female readers may be able to understand: she is one of the three great fashion designers in the 1920s and 1930s, along with Coco Chanel.

Portrait of Madeleine Vionnet, image source: wikimedia

Few people know her family background. Everyone only vaguely knows that she was born in poverty, married very early, and her child did not survive for a year. Later, she experienced marital turmoil and crossed the English Channel to London alone. She worked several temporary jobs and finally became a tailor's assistant. It was probably at that time that Vionnet decided that making clothes was her only career in this life.

When she earned enough money to return to France, the fashion industry was quietly undergoing a transformation. The women's liberation movement that swept the entire 20th century was continuing to brew. Many avant-garde women took the lead in throwing away the rigid corsets that restricted their bodies like a tight hoop. American dancer Isadora Duncan set off a trend by dancing barefoot with her skirt fluttering. This image, as unrestrained and pure as a Greek goddess, struck a chord with young Vionnet. She was determined to make a skirt that was as surging and gentle as water, allowing women to freely show their body curves without being bound.

But how can this be achieved?

She transformed her love for clothing into extremely delicate observation and experience. She played with various fabrics carefully, and inspiration suddenly jumped into her head.

She rotated a thin but textured silk fabric 45 degrees and cut it diagonally. The originally stiff and cramped material, when hung diagonally, unexpectedly showed a flowing and drooping texture. And this drooping texture, on the mannequin used for cutting clothes, outlined a graceful curve.

A dress designed by Madeleine Vionnet in 1925. Image source: wikimedia

This technique was later called "bias cut". The question is, why does bias cut make the fabric look so light and beautiful?

This is a structural engineering problem. Most natural materials, such as cotton and silk, have very low ductility. In engineering terms, the elastic modulus is very large, that is, the ratio of stress to strain is very large - even if you use a lot of force, there is no way to pull it out of a very obvious deformation. On the contrary, things with a small elastic modulus, such as rubber, such as the common cotton fabric containing Lycra, are more likely to deform.

Each thread on the fabric is woven perpendicularly to each other along the warp and weft. Therefore, it cannot be pulled horizontally or vertically. Fabric with a large elastic modulus has a small elastic modulus in diagonal shear, and can stretch in a diagonal direction. The thicker the fiber and the looser the weave, the more it can be stretched, and it looks more drapey.

To understand it more intuitively, you can find a square piece of gauze and compare the elongation of the gauze when it is pulled diagonally and when it is pulled from the opposite side. Image source: wikimedia

The bias cutting technique immediately became a major trend in the Parisian fashion industry, and Vionnet became the "Queen of Bias Cutting".

Vionnet has never studied mathematics or physics, and probably has no idea about terms like "elastic modulus". However, her control over materials shows the beauty of mathematics and engineering. She also cuts the hem of a bias-cut skirt diagonally and inserts parallelogram fabrics, so that the hem falls down layer by layer, like Descartes' leaf line; and her square-cut skirts are also very beautiful, with appropriate materials causing vertical folds like water waves under the shear force of falling.

All this comes from the intuition of the craftsman. Often, the insight and intuition of the craftsman exist beyond theory. This comes from their experience and perception of materials in practice. Similar to Vionnet’s intuition, American sailmakers discovered as early as the 19th century that sails cut and hung at a specific angle would be stronger and more windy, and could leave British sailboats far behind during racing. The principle of sailmakers handling sails is similar to “bias cutting”, but the application direction is opposite - the texture of the canvas when cut straight forms a more stable structure.

Half a century later, this craftsman's intuition played a role again, this time extending to an unexpected field - rockets.

Rocket fuel is divided into two types: liquid and solid. Solid fuel is lighter and easier to control. The only problem is that this plastic material will expand when ignited, which can easily burst the fuel tank .

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In the 1950s, NASA launched several Polaris rockets in succession, but all of them failed and exploded due to similar problems.

James Edward Gordon, a British scientist and one of the founders of materials science and biomechanics, mentioned in his famous work "What is Structure" that engineers working for NASA found inspiration in the bias-cut pajamas that were popular at the time: Could the fuel tank expand and contract slightly in the vertical direction like silk, thereby solving the problem of ignition expansion?

The answer is: Yes.

In the late 1950s and early 1960s, engineers improved the design of fuel tanks by replacing metal materials with extremely low elastic modulus with tempered glass or carbon fiber filaments that were twisted diagonally like a braid , and then filled with heat-resistant materials. When the rocket ignites, these materials will expand and stretch the fuel tank slightly. This will not affect the direction of the fuel force, but also prevent the tragedy of being blown up.

Later rocket fuel tanks all adopted a similar design. Solid fuel is widely used in rocket boosters and plays an important role in the launch of large and small satellites. We can watch TV and use GPS thanks to the invention of "bias cutting".

This craftsman's intuition, coupled with "inspiration" across disciplines and fields, constitutes a turning point in technological innovation. The "upgrade" from craftsman to engineer is a complete and systematic theoretical training. However, what craftsmen and engineers share is indispensable experiential knowledge, which can only be acquired through practice. The focus of practice is not only on the cultivation of practical skills, but also on the cultivation of observation, communication, perception and even empathy, and to use observations in reality to think carefully and to boldly conceive and practice.

For organizations, building an environment that values ​​diversity and cooperation is conducive to the cultivation, transfer and innovation of experiential knowledge. After all, the sources of experiential knowledge are diverse. Nightgowns and rockets are two fields that are completely unrelated, but they can produce "unexpected" connections. This requires organizations to provide a more flexible and free management environment for experiential knowledge.

A research team once went deep into a well-known semiconductor company in Taiwan, China, and learned about their project innovation process. The research found that the new technology required for the project requires cross-institutional cooperation, and what supports this kind of innovation is not only technical conditions, but also management conditions, so that the team can have enough space to communicate, collide, and learn with the outside world, and then transform the knowledge at the experiential level into practical innovation in the form of small-scale experiments.

The power of craftsmen and engineers lies in connecting two unrelated things in the details of the world, and then stitching them together closely with mathematics, physics and engineering. This world is never short of wise and passionate eyes; what we need to cherish is how to cultivate such keen wisdom and give the spark of wisdom the opportunity to shine.

References

[1] JE Gordon (1978), Structures, or why things don't fall down.

[2] https://www.businessoffashion.com/articles/education/madeleine-vionnet-1876-1975

[3] Madelyn Shaw (2006) Textiles and the Body: The Geometry of Clothing, Textile Society of America Symposium Proceedings. 322.

[4] Hung, HF, Kao, HP, & Chu, YY (2008). An empirical study on knowledge integration, technology innovation and experimental practice. Expert Systems with Applications, 35(1-2), 177-186.

Planning and production

Author: Dr. Zheng Li, History of Science and Technology

Review丨Liu Yong, Researcher, National Space Science Center, Chinese Academy of Sciences

Planning: Xu Lai, Ding Zong

Editor: Ding Zong

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Reprinting may lead to copyright disputes