The new design approach for producing carbon fibers with optimized alignment and thickness results in a weight reduction in fiber-reinforced plastics

Carbon is vital to the existence of all living organisms as it forms the basis of all organic molecules, which in turn form the basis of all living things. While that alone is pretty impressive, it has recently found surprising new uses in disciplines like aerospace and civil engineering with the development of carbon fibers that are stronger, stiffer, and lighter than steel. As a result, carbon fiber has adopted steel in high-performance products such as airplanes, racing cars, and sports equipment.

Carbon fibers are commonly combined with other materials to form a composite. One such composite material is carbon fiber reinforced plastic (CFRP), which is known for its tensile strength, stiffness and its high strength-to-weight ratio. Due to the high demand, researchers have carried out several studies to improve the strength of CFRP. Most of these studies have focused on a specific technique called “fiber-guided design” that optimizes fiber orientation to improve strength.

However, the fiber-guided design approach is not without its drawbacks. “The fiber-controlled design only optimizes the alignment and maintains the thickness of the fibers, which means that the mechanical properties of CFRP are not fully exploited. An approach to weight reduction that also enables fiber thickness optimization has rarely been considered, ”explains Dr. Ryosuke Matsuzaki from Tokyo University of Science (TUS), Japan, whose research focuses on composites.

With this in mind, Dr. Matsuzaki, together with his colleagues at TUS, Yuto Mori and Naoya Kumekawa, proposed a new design method for the simultaneous optimization of the fiber orientation and thickness depending on the position in the composite structure, with which they were able to reduce the weight of the CFRP compared to a linear lamination model constant thickness without compromising its strength. Their results can be read in a new study published in Composite structures.

Their method consisted of three steps: the preparatory, the iterative and the modification process. In the preparatory process, an initial analysis was carried out using the finite element method (FEM) to determine the number of layers, which enabled a qualitative weight assessment through a linear lamination model and a fiber-guided design with a thickness variation model. The iterative process was used to determine fiber orientation through principal stress direction and iteratively calculate thickness using “maximum stress theory”. Finally, the modification process was used to make modifications that take manufacturability into account by first creating a reference “base fiber bundle” in an area requiring strength improvement and then determining the final orientation and thickness by making the fiber bundles so were arranged to spread out on either side of the reference bundle.

The method of simultaneous optimization led to a weight reduction of more than 5% and at the same time enabled a higher load transfer efficiency than with sole fiber orientation.

The researchers are enthusiastic about these results and look forward to the future implementation of their method for further reducing the weight of conventional CFRP parts. “Our design method goes beyond the conventional wisdom of composite design and creates lighter aircraft and automobiles that can help save energy and reduce CO2 emissions,” notes Dr. Matsuzaki.


About Tokyo University of Science

Tokyo University of Science (TUS) is a well-known and respected university and the largest scientifically specialized private research university in Japan with four locations in central Tokyo and its suburbs and in Hokkaido. Founded in 1881, the university has continuously contributed to the development of Japan in science by teaching researchers, technicians, and educators a love of science.

With the mission “To create science and technology for the harmonious development of nature, man and society”, TUS has carried out a wide range of research from basic research to applied science. TUS has taken a multidisciplinary approach to research and conducted intensive studies in some of the most important areas of today. TUS is a meritocracy in which the best of science is recognized and promoted. It is the only private university in Japan that has produced a Nobel Prize winner, and the only private university in Asia that has produced Nobel Prize laureates in the natural sciences.

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About Dr. Ryosuke Matsuzaki from Tokyo University of Science

Ryosuke Matsuzaki is Associate Professor at the Institute of Mechanical Engineering at Tokyo University of Science (TUS), Japan. He received his PhD from the Tokyo Institute of Technology Graduate School in 2007 and joined TUS in 2011 as a Junior Associate Professor. His research area is the mechanics of materials with a focus on composites, intelligent materials and structures, and functional materials. He has published 161 articles with over 1900 citations and co-authored 8 books. Further information can be found at: https: // /de /fac /p /Index.PHP 655b

Financing information

This work was supported by the Council for Science, Technology and Innovation (CSTI), the inter-ministerial program to promote strategic innovation (SIP), “Material Integration” for the revolutionary design system for structural materials (funding agency: JST).


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