Explosion is a common phenomenon in the universe. It is of great significance to study the mechanical, physical and chemical phenomena of explosion, master the laws of its occurrence, development and external effects, study and develop the theory and application of explosion science, and prevent and control explosion disasters.
/kloc-in the autumn of 0/950, Ding Xian came back from abroad and was assigned to teach in the Engineering College of North China University. After the national colleges and universities were adjusted from 65438 to 0952, north university of china Institute of Technology was renamed Beijing Institute of Technology, and was identified as the first national institute of national defense technology. Ding Sui devoted himself to national defense teaching and scientific research. 1954, Beijing institute of technology established the first batch of 12 military specialties in China, and co-founded ammunition charging specialty with Chen, Ding Xian and others. After offering a series of courses such as chemical engineering principle, ammunition charging technology, initiating explosive device and pyrotechnics technology, he devoted himself to the construction of explosion theory and application. 1958 In Beijing Institute of Technology, he was responsible for the construction of the first explosion tower with a diameter of 6m in Beijing, and then successively carried out research on shaped charge and fragmentation. 1959 cooperated with yun shourong to publish "discussion on jet mechanism of пг-2 bomb hollow charge", and 196 1 year published the textbook "principle of explosion". 1963, Ding Xian and Yun Shourong jointly published The Deformation of Hollow Sphere under the Action of Explosives, and enrolled the first batch of graduate students in explosive physics in China. Cui Chunfang, a graduate student of 1964, made a numerical calculation under very simple conditions and published the Approximate Solution of Convergent Detonation Wave on a Sphere (Column). In the early 1960s, Ding Xian led the teachers and students of this discipline to conduct anti-design research on the power and structure of surface-to-surface, surface-to-air and air-to-air missile warheads imported from the Soviet Union. 1963, together with professor Zhou faqi, led dozens of teachers and students to participate in the national 142 mission, and set up the 032 scientific research group to carry out a series of work such as new explosive synthesis, explosive modification, molding powder development, precision charge molding processing technology, explosive performance test and long-term storage. After two years' efforts, two kinds of high explosives with high detonation performance, good storage stability and HJJ with excellent performance have been developed successively, which have been highly praised by famous scholars and leading departments such as Professor Wang.
At the 142-2 meeting held in 1963, Ding Wei put forward important opinions on detonation research, and clearly pointed out that it is not appropriate to pursue explosive detonation speed and single index breakthrough without considering detonation pressure and explosive safety. It is necessary to strengthen the theoretical research on explosive detonation and standardize the test methods of various properties of explosives. The higher authorities adopted this suggestion, and set up the detonation physics group in 1964, and appointed Professor Guo Yonghuai, deputy director of the Institute of Mechanics of Chinese Academy of Sciences, as the team leader and Professor Ding Wei as the deputy team leader. At the same time, a technical group for testing the performance of high-efficiency explosives was established, with Professor Ding Nai, Professor Xu Kang as deputy heads respectively. 1966 formulated the performance test method of high-efficiency explosives, which was issued by the scientific research bureau of the State Council National Defense Industry Office to all relevant units in China.
While completing a series of scientific research tasks such as 142 national major scientific research tasks, a variety of large and medium-sized precision instruments, high-voltage oscilloscopes, high-speed cameras, charging processing and explosive performance testing equipment were added, which made the explosion technology laboratory reach the advanced level in China at that time; A number of high-level technical backbones have been trained. This period also trained the first batch of graduate students in the field of explosion research in China, who have now become the backbone of achievements.
1977, Beijing University of Technology resumed the enrollment of undergraduates in explosive technology and charging specialty; 1980, Master of Explosive Mechanics Project; 1984 established the first doctoral program in explosive mechanics in China, with Professor Ding Xian as doctoral supervisor. From 65438 to 0987, the subject was renamed explosion theory and application, and was rated as a national key subject by the State Education Commission. With the approval of the State Planning Commission 1988, the State Key Laboratory for the Prevention and Control of Explosion Disaster was established on the basis of this discipline, and a number of internationally advanced instruments and equipment were purchased with loans from the World Bank, which significantly improved the teaching and scientific research conditions of this discipline. 199 1, a postdoctoral mobile station is established in this discipline. Chen Nengkuan, academician of China Academy of Sciences and deputy director of the Science and Technology Committee of the Commission of Science, Technology and Industry for National Defense, Jing, academician of China Academy of Sciences and director of the National Defense Key Laboratory of Shock Wave Physics and Detonation Wave Physics, and Zhang, director of the Science and Technology Committee of Southwest Institute of Fluid Physics, and other experts were hired as part-time doctoral tutors. Huang Chunping, chief expert of 863-409 high technology, and Zhang Xinwei, researcher of Beijing Institute of Applied Physics and Computational Mathematics, are part-time professors. Young people from Peking University, China University of Science and Technology, National University of Defense Technology, China Academy of Engineering Physics, Xi Institute of Modern Chemistry, Beihang University and other schools and research institutes come here to study for master's and doctor's degrees, or enter postdoctoral mobile stations to engage in scientific research.
With the strong support of leaders at all levels and under the personal leadership of Professor Ding Xian, the discipline of explosion theory and application has been established and is developing steadily. This subject has trained and brought up a group of high-level scientific and technological backbones loyal to national defense, and established a laboratory with good experimental conditions. Since the late 1970s, Ding Kui has led an assistant to study the detonation infrastructure. By the mid-1980s, advanced electromagnetic and manganin piezoresistive testing systems had been built successively, and a variety of Lagrangian sensors and their analysis technologies had been designed and developed, which provided necessary means and methods for studying shock wave initiation, constitutive relation, state equation of explosion products, phenomenological reaction rate and the relationship between components and technology.
The electromagnetic method test system is equipped with a large Helmholtz coil made of stainless steel plate with a diameter of 1m and its power supply system, a digital storage oscilloscope with a sampling rate of 100MS/s and a data communication interface. The maximum bandwidth of the whole system is not less than 30MHz, and the digital recording, copying, microcomputer communication and access of particle velocity or pulse analog signals on a certain section in the measured medium are realized at the earliest in China. The configuration and testing technology of this system has reached the first-class level at home and abroad.
In terms of manganese-copper piezoresistive testing technology, Professor Ding's assistants successfully solved the sub-microsecond high-speed synchronous pulse power supply technology; Expand the pressure range to MPa level; Using Kangtong stretch compensation technology, the application scope is extended to non-planar symmetric stress state, and many national patents are obtained. Many domestic research institutions have successively applied these technical achievements.
1In June, 985, Ding Wei delivered a speech entitled "Lagrangian Analysis of Reaction Flow Burning Behind Shock Front" at an academic conference held in Poland, and the report was also published in the English journal Archivum CombuStionis jointly published by the former Soviet Academy of Sciences and the Polish Academy of Sciences. Dovich (зелдович), a famous scientist in the former Soviet Union, attended the meeting, and this article was appreciated by яич. In July of the same year, Ding Wei went to the United States to attend the Eighth International Detonation Conference, and made a report entitled "Rain Gogneau Sum Reaction Rate from EMV Gauge Measurement and Lagrange Analysis" at the conference, which was widely welcomed. Compared with the articles read by American scholars at the conference, the work of Ding Wei and others has reached the international advanced level in directly studying the detonation performance of explosives and the behavior under the action of shock waves by using electromagnetic velocimetry (EMVG) and Lagrangian analysis (RFLA), which also shows that China has excellent and reusable magnetic field devices and electromagnetic method testing systems. The paper "Study on Impact Detonation Characteristics of Explosives by Particle Velocimetry and Laplace Analysis" is unique in that the whole particle velocimetry and Laplace analysis method are applied to the study of explosive detonation performance, and two dimensionless parameters are proposed, which can be used as criteria for evaluating the reliability and safety of explosive initiation under the same experimental conditions. Ding Wei and Huang Zhengping deeply and carefully analyzed the influence of the conductivity of detonation products on the measurement of electromagnetic velocimeter, and put forward the corresponding mathematical and physical model and experimental method, which made the research of electromagnetic method in China enter the advanced ranks at home and abroad.
Since 1980s, Ding Wei and Huan turned one of their research focuses to two-dimensional detonation and its measurement technology. Many practical problems in detonation research are two-dimensional axisymmetric problems, so it is obvious that one-dimensional test and analysis technology cannot be used. 1986 A Laplacian meter for measuring two-dimensional dynamic high-pressure flow field was developed, and a two-dimensional Vera analysis method was proposed, which was published in the proceedings of the conference on condensed impact compression hosted by american physical society in 1987. 19871June 12, Ding Wei gave a speech entitled "Sound Velocity Surface and Flow Field in Two-dimensional Detonation Reaction Zone", and put forward the generalized C-J condition in cylindrical symmetric two-dimensional steady detonation system. Explosion and shock 1 period 1989 put forward five characteristic quantities of reaction, namely, reaction degree, reaction rate, volumetric energy release rate, instantaneous reaction heat and thermal coefficient. These characteristics can be calculated from the P-T data measured by Willard flowmeter. 1990 made a summary of his work in Actamechanica for several years. This research, which lasted for many years, won the second prize of 199 1 national defense scientific and technological progress and the third prize of national invention.
During the period of 1989, Ding Wei gave a report on "Response of Composite Propellant to Impact Load" at the 9th International Detonation Conference, and reported some work on safety research of solid composite propellant. The dynamic responses of two solid composite propellants under shock wave pressures of 2.0GPa and 10.0GPa were measured by electromagnetic velocimeter and manganese copper manometer. Firstly, it is found that there is a stage of non-reaction or extremely slow reaction in the reaction process of composite propellant. The response of oxidant (AP), binder (HTPB, Thiokol), the mixture of AP and aluminum powder, and the mixture of AP and binder to impact load were also studied.
Ding Nai, Bai Chunhua and Huang have been engaged in solid propellant safety research for nearly 8 years, and have published more than 20 papers at domestic and international academic conferences such as Explosion and Impact, Journal of Aerospace, Journal of Ordnance, etc. A relatively complete research system is established, including impact failure performance research system, shock wave initiation and detonation process research system and detonation risk assessment system. The main progress points are as follows: (1) The dynamic fracture is divided into two stages: dynamic compression and dynamic tension for the first time, and the test method and device are successfully designed. (2) Using special substrate materials and Laplace piezoresistive sensor technology to measure spallation signals, compared with VISAR measurement by Weirick et al., it has higher accuracy. (3) The internal failure process and delamination nucleation mechanism of solid propellant under shock wave compression were studied by soft recovery and scanning electron microscopy, which provided strong evidence for establishing theoretical model. (4) A brittle fracture model of solid propellant is proposed, which can describe the process of crack nucleation, propagation and polymerization, and a numerical simulation program is compiled. (5) The impact and detonation flow fields of solid propellant are directly measured by Daulard meter for the first time, which improves the measurement accuracy. (6) Through theoretical analysis and comparison, Laplace analysis technique suitable for different conditions is established to describe different states and multivariable reaction processes. (7) The state equation and reaction rate equation of solid propellant are determined, and the calibration method of reaction rate equation of solid propellant is put forward. On this basis, a program for simulating the process of shock wave to detonation and detonation is compiled. (8) Considering the factors of viscoelasticity, compressibility, heat conduction and thermal decomposition, the hot spot formation and ignition model of composite propellant is established, and the corresponding numerical simulation program is compiled. (9) The method of analyzing and evaluating detonation risk by using the flow field behavior from shock wave to detonation is put forward for the first time. (10) puts forward the concept of minimum critical initiation pressure and establishes a quantitative method, which is consistent with the large-scale test results in the United States, saves the test cost and has good economic benefits.
Four typical solid propellants in China were studied by using the above research system, and the following important results were obtained: (1) Under the impact load of 50MPa, the energetic components (HMX and AP) in the solid propellant began to break, and the modified double-base propellant was debonded from the matrix at the same time, which could not be detected by conventional large-size grain detection methods. (2) The dynamic process of solid propellant spalling is that microcracks nucleate, grow, polymerize and form fragments, and microcracks begin with the fracture of energetic components. (3) The chemical reaction process of double-base propellant under impact load is similar to the detonation of heterogeneous explosives, and the main components react in parallel. (4) The chemical reaction process of composite propellant under shock wave is obviously different from that of double-base propellant, which has three reaction stages, and the pressure and particle velocity have two peaks. The chemical reaction time in the process of detonation is about 65438 0.0μ s (5). Compressibility and viscoplasticity are the main factors that affect the formation and ignition of hot spots in composite propellant, and heat conduction can be ignored, and hot spots form around microcavities in propellant. When the ignition time is less than 0. 15μs(5), the pre-impact damages the interior, and the process of propellant from impact to detonation changes. With the increase of damage degree, the initial flow field changes from double peak to single peak. (7) The detonation sensitivity of modified double-base propellant increases with the increase of HMX content and the decrease of density. (8) The shock wave grows into detonation wave in double-base propellant, which is mainly the result of the reaction near the wave front; In composite propellant, it is mainly the result of strengthening the flow field before and after the wave. In this way, when the grain size is small and the impact time is short, the composite propellant is not easy to detonate, while the double base propellant is less affected by these factors. (9) The critical initiation pressures of double-base propellant, modified double-base propellant and composite propellant are 6.0, 3.0 and 20GPa respectively. The minimum critical pressures of (10) modified double-base propellant and composite propellant under one-dimensional continuous loading are 1.0 and 1.8 GPA respectively. This result can be used to analyze the detonation risk of large and medium-sized grain under long-term continuous loading, which is close to the large-scale (about 2m) test results of modified double-base propellant and composite propellant in the United States (1.0 and 2.5GPa), but the test cost is much saved. The research results in this field have passed the ministerial appraisal and are considered as "the first in China, but not reported abroad".
In the early 1980s, Ding Wei carried out research on shock wave chemistry and dynamic response of materials to shock wave compression. 1984, leading students to do research on shock wave polymerization of hydroquinone and shock synthesis of tungsten carbide. 65438-0988, supported by the national natural science foundation project "Study on shock wave solid-state chemical reaction", carried out research on shock wave compaction of powder mixture, synthesis of Ni-Al compound and impact response of tungsten alloy. He instructed Xiong Yingming, a doctoral student, to complete his dissertation "Microstructure Response and Macro-Constitutive Behavior of Tungsten Alloy Materials at High Strain Rate", and studied the dynamic mechanical properties of 93 tungsten alloy in the range of strain rate1.4×104 ~ 2×106s-1,and found that it has nonlinear elasticity and impact toughness. August 1990 International Symposium on Shock Wave and Dynamic Response of Materials with High Strain Rate was held at the University of California, San Diego, USA. At the invitation of the conference, he gave a report on the research progress of shock wave in China, and summarized the work of China in 1980s, including metal explosive forming and hardening, explosive welding and recombination, dynamic fracture and spalling, impact compaction of powder, impact-induced reaction and so on. The invention of black powder is one of the four great inventions in ancient China. It is a household name in China, but not in the United States. 1980 The Seventh International Fireworks Conference (IPS) was held in the United States, and the leaders of the Ordnance Industry requested Ding Xian to lead the team. At the meeting, he gave a speech on the development of gunpowder and pyrotechnics invented by China. To his great surprise, many American and European scholars at that time expressed their surprise with one voice, saying that they had never heard of China inventing gunpowder. Traditional middle school textbooks all say that Roger Bacon invented it, and Ding's report corrected their wrong views. After he returned to China, he reported this situation in the study of the history of science and technology, especially in the editorial group of the Encyclopedia of China Military Volume, which aroused widespread concern. Ding Nai was responsible for writing the article "Ancient Gunpowder in China", which clearly pointed out: "Modern black gunpowder was developed from ancient gunpowder in China. Gunpowder is the first explosive mastered by human beings and one of the four great inventions in ancient China, which once played an important role in the world. " Therefore, he did a lot of research on the invention of ancient gunpowder in China, its early military application, the development of gunpowder technology and the discussion of ancient gunpowder theory. 1985, when he visited Cambridge University in England, he specially visited Professor Joseph Needham, a famous writer in the history of Chinese culture, science and technology, and expounded his views on the above issues, which was fully agreed by Joseph Needham. 1987, at the invitation of Japan Industrial Gunpowder Society, a speech entitled "Gunpowder in China: Past and Present" was delivered in English, translated by Tadao Yoshida, a professor at Tokyo University, and published in the first issue of Volume 49 of Japan Industrial Gunpowder Journal. 1990 At the 15th International Symposium on Initiating Explosive Devices held in the United States, he gave a report entitled "Invention and Discovery of Gunpowder and Shock Wave in China", explaining in detail the origin, theory and history of military application technology of gunpowder, which was warmly welcomed.
After textual research, Ying Xing in the Ming Dynasty first described the shock wave. See 1637 for the description of shock wave, which was reported in the conference on shock compression of condensed matter hosted by american physical society-1989. Ding Nai also studied the article "On Qi" in Song Dynasty, and contacted his own research on black powder and the description of thunderbolt and thunderbolt power in some historical books, and came to the conclusion that gunpowder explosion in Ming Dynasty could completely produce shock waves. Influenced by his family, Ding Nai learned the truth of patriotism and saving the country from an early age. When he was still studying in Zhejiang University, he joined the China Society, a progressive student organization. As of 1944, Zhejiang University has moved to Zunyi, Meitan and other places in Guizhou. At this time, the Japanese invaded Hunan and Guangxi. The students of Zhejiang University were very indignant at the fleeing behavior of the Kuomintang troops, so they formed a "Field Service Corps", with President Zhu Kezhen as honorary head and Chairman Zhi Deyu and Ding Wei as deputy heads, and went to the front to carry out a morale-boosting labor force. After returning to teach at Zhejiang University from Yumen Oil Mine, he began to serve as the director of the progressive organization "People's Century Creation Society" (hereinafter referred to as "People's Creation Society"), responsible for the propaganda work of "People's Creation Society", editing the Times Construction Newsletter, studying progressive newspapers such as Wen Wei Po and Huashang Daily, learning the land law promulgated in the liberated areas and other materials, and organizing progressive teachers and students to participate in the anti-hunger in the Kuomintang-controlled areas.
After studying in the United States, Ding Nai had a deeper understanding of the backwardness and corruption in old China, and his patriotic enthusiasm was even higher. He has frequent contacts with progressive international students, always keeps in touch with China and carries out various progressive activities.
194865438+In February, in Chicago, together with Ge Tingyi and Feng, the "American-Chinese Association for Science and Technology" was founded. 1949 65438+ 10. In view of the rapid development of the domestic revolutionary situation, Ding Wei organized a gathering of old members and other international students organized by China Association for Science and Technology to discuss what international students should do for the new country after the founding of New China. 1949 In June, the China Association of Scientists Studying in the United States, initiated by Ge Tingsui, Hou Xianglin, Hua, Ding Ying and others, was formally born in Pittsburgh, USA. The inaugural meeting adopted the declaration drafted by Ding Sui, and was elected as the executive director of the American Association for Science and Technology for Studying Abroad by voting.
After the birth of the American Association for Studying Abroad, American regional chapters were established one after another, and the members of the association developed rapidly. 1August, 949, there were 19 regional chapters with 4 10 members; By March of 195 1 year, the number of districts will increase to 32, with 7 18 members. Ding Wei is responsible for editing the Newsletter of the US-China Association for Science and Technology, and assisting in editing and publishing the Newsletter of the US-China Association for Science and Technology. Focusing on the domestic situation, he reprinted newspaper articles in the Liberated Areas and Hong Kong, and published information and letters from members of the US-China Association for Science and Technology who returned to China to participate in the construction of a new China, so as to unite and inspire students studying in the United States. At the annual meeting of the American Association for Science and Technology held in June 1950, Ding Nai presided over the meeting, and established the work focus of "knowing the new China, preparing to go back to China to participate in construction, and making all preparations for returning home" to mobilize overseas students to go back to China to participate in socialist construction. 1950 In September, he returned to his motherland and attended the first National Day ceremony of New China in front of Tiananmen Square.
After the Korean War broke out, McCarthyism in the US Congress was rampant. The "Committee on Non-American Activities" and the Federal Bureau of Investigation of the United States listed the Association for Studying in the United States as an illegal organization, persecuting progressive China students. In this case, in view of the fact that quite a few members of the American Association for Studying Abroad have returned to China one after another, and many of the remaining members are preparing to return to China, the American Association for Studying Abroad officially announced its dissolution on September 1950.
Although the history of the American Association for Science and Technology is less than two years, nearly 800 China students have joined the organization, and more than 400 members have returned to China in the early days of liberation, which has sent a group of outstanding scientific and technological talents to the new regime. They have made important contributions to the construction of new China. In his teaching career of more than 40 years, Ding Xianpei has trained a large number of senior professionals. While cultivating a large number of undergraduates, he directed 12 graduate students from 1956 to 1966. 1978 after the resumption of postgraduate enrollment, master's and doctoral students will be enrolled. In 1990s, a postdoctoral mobile station specialized in explosion theory and application was established. Up to now, it has trained 0/2 master students, 0/6 doctoral students and 3 postdoctoral students. Under his careful training and guidance, many of these students have become the backbone of teaching, scientific research and production departments, and some have become doctoral supervisors, well-known experts and leaders of enterprises and institutions.
In teaching and educating people, Ding Xian emphasized that teachers should pay equal attention to both words and deeds. He often educates students with his own personal experience: "Scientists have a country and should first serve the motherland and the people." After the reform and opening up, in view of some graduate students' ideological trends such as uneasy study and wanting to go abroad, he patiently did ideological work for students. He warned the students: "On the basis of what we have, it is entirely possible to catch up with the advanced world level in some areas of this discipline in a short time."
Ding is meticulous and strict with his students in his academic attitude. When guiding graduate students, special emphasis is placed on the quality of papers. He believes that quality is the life of a paper, and the quality of a paper is reflected in its advanced nature and creativity. He asked graduate students to aim at cutting-edge topics in the world, and encouraged them to make bold innovations and make high-level papers. He also pays attention to cultivating students' pragmatic and rigorous work style. After the student's paper was finished, he carefully examined it and revised it carefully. He often warns students that "scientific research must be honest and not false at all." If an opinion is not your own, you must indicate the source. " From 1988 to 199 1, he has been thinking about the progress of doctoral thesis in China during his lectures in the United States. He insisted on writing a letter to doctoral students every two weeks, which not only guided the work of doctoral students, but also introduced the latest development of explosive science abroad and the latest academic achievements in doctoral research. He copied the information and sent it back to China to write a thesis for doctoral students. In less than two years, his doctoral students in the United States have received more than 40 letters from him.
Ding Wei treats his students as both a strict teacher and a loving father. Whether discussing problems or chatting at home, he treats them equally. Students have difficulties in life, and he will do his best to help them; When students encounter ideological problems, he will patiently enlighten them. On holidays, he invited graduate students to his home, and his mother cooked a sumptuous meal, so that students could improve their lives, enjoy the warmth of a family and deepen the affection between teachers and students. Ding's ideological and moral character, academic attainments, research methods and life style have had a great influence on the growth of students.