Face up to the problem
Traditional processing methods seriously restrict the popularization and application of carbon fiber composites. To this end, Jia Zhenyuan's team conducted interdisciplinary integration research and opened up a new theoretical system suitable for carbon fiber composite processing.
When the structural weight of a civil airliner is reduced by 1%, its fuel consumption can be reduced by 3% to 4%. For every weight loss 1% of high-speed rail, its energy consumption can be reduced by 6% to 7%. ...
For the high-end equipment field of "one gram of weight is one gram of gold", whether flying in the sky or running on the ground, only by reducing the weight can the structural efficiency and equipment performance be improved.
To this end, a battle for advanced materials triggered by "losing weight" has already swept the world. "Carbon fiber composites are the first choice for weight loss and efficiency improvement in high-end equipment. The more they are used, the more advanced the equipment performance." Jia Zhenyuan said.
However, the lag of process technology is difficult to support the innovative application of materials, which makes carbon fiber composites encounter a lot of problems once they appear. Jia Zhenyuan told the Economic Daily reporter that traditional processing can only be done by hand, with low quality and low efficiency. The machined components are prone to burr, tear and delamination, and the machining damage is random and uncontrollable, which can not meet the high performance requirements of carbon fiber composite components, which seriously restricts the popularization and application of materials.
"From 2005 to 2009, although we solved the problems encountered in the processing of composite components in some aerospace enterprises, the improvement of processing quality was limited to a certain extent because of the traditional cutting theory of homogeneous materials such as metals used in the project, but the characteristics and structure of carbon fiber composites were completely different from them, and they were typical difficult to process." Gao Hang, the backbone of the team, said.
After repeated discussions, Jia Zhenyuan decisively put forward: "We must break through the shackles of the traditional theoretical system of cutting homogeneous materials such as metals, open up and establish a new theoretical system suitable for the processing of carbon fiber composites, and solve the problems from theory to engineering."
To establish a theoretical system, we must make a breakthrough on the basis of predecessors. The practical problems forced Jia Zhenyuan's team to explore the territory and create a new world in basic theoretical research. To this end, the team intensified the research on the cross-integration of materials, mechanics, machinery and other disciplines, thoroughly figured out the causes of processing damage from the characteristics of carbon fiber composites and the process of material removal, and then studied the principle of low-damage processing and the guarantee method of high performance of components.
Bite hard bones and fight hard. Finally, Jia Zhenyuan's team made breakthroughs in a series of key links, revealed the removal mechanism of carbon fiber composites and the formation mechanism of machining damage, put forward the cutting theory for carbon fiber composites processing, established the dynamic simulation model of cutting force and cutting process, and realized the original innovation of cutting theory.
Breakthrough application
Jia Zhenyuan's team tried process innovation and developed 13 sets of NC machining process equipment, which filled the gap in China and became the key equipment for machining several key composite components in China's aerospace industry.
"Large foreign companies spend a lot of money and time, which is time-consuming and labor-intensive. The experience finally explored is the core secret of the enterprise and will not tell us. " Jia Zhenyuan said, "It is impossible to follow and lead in a short time without the support of basic research."
Backed by solid theoretical innovation and immersed in practical application, it is a scene of "another bright future village".
Jia Zhenyuan's team put forward the principle of minimizing the damage of micro-blades, cutting chip grooves on the cutting edge of spiral grooves to form micro-teeth, and realizing the "micro-element removal" in the machining process; Through the clever design of tools and the cooperation of cutting actions, the "reverse shearing principle" was invented, which effectively cut off the surface fibers. In addition, nine series of drilling and milling tools have been developed, realizing high-quality processing of carbon fiber composites, with service life 2 to 7 times longer than that of imported tools, and the price is only 1/6 to 1/4.
Not only that, they boldly tried technological innovation, invented in-situ accompanying machining method, low-stress flexible tooling and follow-up dust removal device, and developed 13 sets of NC machining process equipment, which filled the domestic blank and became the key equipment for machining several key composite components in China's aerospace industry.
Since 20 10, the newly developed technical equipment and tools have been put into use, which has reduced the processing damage of composite materials from the original centimeter and millimeter order to below 0. 1 mm, realized the leap from impossible or manual processing to low-damage digital processing, and the processing technology has leapt to the international leading level.
Gao Hang told the Economic Daily reporter that once, he took his student Bao Yongjie to an airline to sell their knives. The company doesn't believe in the performance of the tool, but simply puts forward the problem of "let the tool process 100 holes continuously". Master and apprentice held the composite board at the scene, actually drilled 100 holes, and each hole went smoothly, and finally won the trust of the enterprise.
Nowadays, the basic theory and processing technology are two-way escort, so that a series of ingenious tools and processing equipment write the legend of "Made in China".
New aerospace equipment cockpit, special-shaped deep cavity of aircraft parts, edge contour and super-large hole of large thick plate in wing structure of aviation equipment, helicopter rotor and tail series, composite/aluminum laminated verification piece of large passenger aircraft fuselage section, high-speed rail composite fuselage test piece ... All these processing problems of key parts of big countries' heavy equipment were solved by Jia Zhenyuan's team, which made outstanding contributions to the development, finalization and mass production of major national equipment and key models, and have been successfully applied to the First Aerospace Hospital.
Find the right direction
Jia Zhenyuan's team believes that to engage in scientific research, it is necessary to increase original basic research, form enterprise demand, and build a innovation chain of basic research, applied basic research, technology development and product development.
"Find the right way to do scientific research." This is a sentence that Jia Zhenyuan often hangs on his lips: "There are many people who work hard, and the key is to find the right direction. The right path may get twice the result with half the effort; If you go wrong, you may not succeed if you make great efforts to make a big circle. "
"Our difficulty lies in finding out how the problem arises. Because the factors affecting the processing damage of carbon fiber composites are very complicated and the forms of processing damage are various, the whole research process is full of challenges. " Team member Wang Fuji said, "It takes hundreds of experiments to create a theoretical research model, invent new tools and design new processes."
From theory to practice, this technological invention has won many firsts in research methods and means, and continuous innovation runs through the research process of every member of Jia Zhenyuan's team.
"Teacher Jia always has books on various composite materials on his desk. As long as he has time, he will find relevant graduate students and teachers to discuss the technical scheme and existing problems of the project. " Wang Fuji recalled.
Jia Zhenyuan and Do not forget your initiative mind, vice president of Dalian University of Technology, stick to the front line of scientific research. But only he knows how much responsibility and pressure there are. "Even when I was eating and sleeping, I was thinking about the research of this subject."
It is the scientific research attitude that Jia Zhenyuan's team has always adhered to to to unite all forces to break through the major national demand problems. Jia Zhenyuan told reporters: "Scientific research must serve the major needs of the country." This awareness comes from his profound understanding of going deep into enterprises and serving the production line for more than 30 years. "If our engineering teachers only engage in R&D from the perspective of the school, the research results will be difficult to' land' and may be abandoned in the laboratory, which will not form productivity."