Opportunities and Challenges of Civil Composite Materials

　　China's "Twelfth Five-Year Plan" for the Development of Strategic Emerging Industries clearly states: "The new materials industry should vigorously develop new functional materials, advanced structural materials, and composite materials; conduct research and industrialization of common basic materials; establish a certification and statistical system; and guide the adjustment of the materials industry structure." Advanced composite materials, in particular, hold an important position in the field of new materials technology and play a crucial role in promoting high-tech modernization in both military and civilian fields worldwide, therefore receiving significant attention in recent years.
　　Advanced composite materials, represented by carbon fiber reinforced resin matrix composites, have been primarily used in aerospace since their inception in the mid-1960s, accounting for approximately 70% to 80% of the market share. However, in recent years, they have rapidly expanded into three major areas: aerospace, sporting goods, and industrial applications. In the future, aerospace and other military applications will account for approximately 20% of the market share, sporting goods will account for approximately 30%, and industrial applications will account for over 50%. Advanced composite material technology is a typical dual-use technology, with the transfer of high technology to civilian use becoming a global trend. The application of composite materials in various industrial fields is showing a trend and characteristic of diversified development.
　　In the aerospace and sporting goods sectors, the application of composite materials still enjoys a stable market and demand, with the former maintaining steady growth. In infrastructure, the most widely used composite materials are currently in the form of wrapping materials and laminates for infrastructure repair, renewal, and reinforcement. However, the application of this technology in China is slow, while internationally, building repair composite materials have become an industry.
　　In the automotive field, due to the relatively high material and manufacturing costs of composite materials, progress has been unsatisfactory. However, in recent years, with the emergence of low-cost materials and the development of low-cost technologies, the application of composite materials in automobiles is showing good development momentum and is expected to see significant growth in the near future. It also represents a large potential market for composite materials. In the wind power generation field, as blade lengths continue to increase, higher demands are placed on material strength and stiffness, leading to the extensive use of carbon fiber as a reinforcing material. According to predictions by the European Wind Energy Association and the American Wind Energy Association, the global wind energy industry will continue to maintain an average double-digit growth rate over the next 10 years, with China in Asia and the United States in North America continuing to be regions with high growth potential. Advanced composite materials also have broad application prospects in the oil and gas, rail transit, electronics, bioengineering, and biomedical fields.
　　Composite material technology is a highly applicable new technology, but practical applications have also revealed that composite materials are relatively expensive, particularly in manufacturing costs, which has become a major obstacle to their further development and application. In view of this, the issue has received widespread attention worldwide, with Western developed countries, led by the United States, developing low-cost composite material development research plans, which have already yielded significant results. The low-cost development of composite material technology is currently a core issue in the global development of composite material technology. Low-cost composite material technology includes the following key aspects:
　　Low-cost design technology. Developing design and manufacturing technologies centered on DFM (Design for Manufacture). In essence, with the advancement of computer and manufacturing technologies, this involves adopting new design concepts and methods, developing digital and automated manufacturing technologies, and further integrating design and manufacturing to accelerate product development, improve quality, and reduce costs. The development and integration of a large number of design software packages, coupled with automated manufacturing technologies, considers manufacturing and assembly issues at the design stage, which not only reduces the number of parts but also ensures structural reliability.
　　Low-cost material technology. This technology includes the application of large-tow carbon fiber, the development of low-temperature, rapid-curing resin systems, low-cost prepreg technology, the supporting research and development of various VARY resin systems, the rational use of thermoplastic composites, and the rational application of hybrid composites, among other technologies.
　　Low-cost manufacturing technology. Manufacturing costs account for approximately 80% of the total cost of composite parts, so low-cost manufacturing technology is the core of low-cost composite material technology. Its main aspects include: (a) automated manufacturing technology; (b) large-area integral molding technology centered on co-curing/co-bonding; (c) VARY molding technology; (d) out-of-autoclave molding technology.
　　Composite materials are currently developing towards lightweight, high-performance, and multifunctional aspects. Industrial applications of composite materials are the future direction of development. China will not only be a major producer of composite materials but also a major user. However, compared with foreign countries, we still have a certain gap in materials and technology. The application of composite materials in industrial fields still faces many challenges: the price of carbon fiber is not low enough, and only by expanding applications can the price of carbon fiber be reduced; rapid and low-cost manufacturing technologies suitable for industrial products are not yet mature. Creating a full-process platform for composite material structural design, strength analysis, rapid manufacturing, and application verification can promote the development of this technology; composite material repair technology needs to keep pace; and after widespread application of composite materials, effective methods for recycling waste materials are still lacking, which is particularly prominent for thermosetting resin-based composite materials.