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Li Yinshan's main experience
Li Yinshan

Li Yinshan, male, 196 1, born in Pingyao County, Shanxi Province, graduated from the Institute of Ordnance Engineering. His main works are Theoretical Mechanics of Maple Leaf I and I and II.

Chinese name: Li Yinshan

Mbth: Li Yinshan

Nationality: China.

Ethnic group: Han nationality

Place of Birth: Pingyao County, Shanxi Province

Date of birth: 196 1 year

Occupation: teacher

Graduate school: ordnance engineering college

Main achievements: continuous piecewise independent integral method

Masterpieces: Maple theoretical mechanics I, I and II.

Research direction: impact dynamics; Rotor dynamics

Character experience

Born in 196 1, Pingyao County, Shanxi Province;

1983 graduated from ordnance supervision department of ordnance engineering college (undergraduate);

1993 Master of Engineering Machinery, Taiyuan University of Science and Technology;

1999 received a doctorate in solid mechanics from Taiyuan University of Technology;

In 2002, he left the postdoctoral mobile station of general mechanics in Tianjin University to work in Hebei University of Technology, and successively served as a lecturer (1994), an associate professor (2000) and a professor (2003).

In 2006, it was selected as "the sixth batch of young and middle-aged backbone teachers in colleges and universities" by the Education Department of Hebei Province.

research direction

The research direction is nonlinear dynamics and its control (bifurcation, chaos, nonlinear vibration, etc.). ); Impact dynamics; Rotor dynamics; Intelligent structural dynamics, structural reliability optimization design.

Main contribution

research results

In the field of solid mechanics, the experimental study of bifurcation and chaos is mostly limited to beams. So far, there is no report about the experimental study of plate (or shell) chaos. Li Yinshan and Yang Gui designed a nonlinear circular plate chaotic experimental shaking table. The nonlinear dynamic behavior of axisymmetric circular plate under harmonic load is systematically studied from three aspects: experiment, theory and numerical value. Complex dynamic behaviors such as chaos, symmetry breaking and recovery, amplitude and phase modulation, sudden change (or jump) and superharmonic bifurcation were found in the experiment. The following conclusions are obtained: symmetry breaking phenomenon is due to the appearance of structural frequency components of symmetric dynamic system solutions: even-order overshoot and solution; Even reconciliation; Even order harmonic solution and even order harmonic solution. Before chaos appears, one of the above four solutions must appear, so symmetry breaking phenomenon is the precursor of chaos.

Nonlinear dynamic instability of rotor system has always been one of the important research topics in modern rotor dynamics. Many instability accidents of steam turbine-generator sets at home and abroad show that the nonlinear instability analysis of rotor system under large disturbance has become an important research topic. Although many mathematicians, mechanics and engineers have made unremitting efforts in stability research, for a long time, stability research has been limited to low-dimensional qualitative theory and linear system stability quantitative theory, such as Floquet theory. Li Yinshan and Chen Yushu put forward the relative positive area criterion which is suitable for the quantitative problem of rotor steady stability. CPAC can be used to quantitatively analyze the stability and calculate the safety margin of high-dimensional nonlinear rotor system.

Publishing books

Maple theoretical mechanics

This book corresponds to classical theoretical mechanics in content, and basically covers all the problems involved in classical theoretical mechanics-statics, kinematics, dynamics, dynamic topics and advanced applications. This textbook focuses on "mechanics" from beginning to end. Computer programming is first of all computer modeling training, followed by "calculation" and "application". Compared with classical theoretical mechanics, this textbook is oriented to "human brain" and this textbook is oriented to "computer". "Program" is the carrier of "computer" thinking and the tool for "human brain" to guide "computer" thinking. Using "computer" to analyze theoretical mechanics is essentially using "program" to analyze and calculate the mechanism and structure composed of particles and rigid bodies.

Maple material mechanics

This book is a companion of maple theoretical mechanics. This book corresponds to the classical mechanics of materials in content, and basically covers all the problems involved in classical mechanics of materials-strength, stiffness, stability, dynamic load, energy method and optimal design. Based on mechanics from beginning to end, this book uses computer technology to program, model and analyze the mechanics of materials, and analyze and calculate the structure composed of elastic bars and bar systems. The characteristics of this textbook are: this book integrates the whole process of solving practical problems, including mechanical modeling, mathematical modeling, computer programming, symbolic operation, numerical calculation, computer drawing and other steps, and is an innovative material mechanics textbook for quality education. This book is suitable for the teaching of material mechanics for engineering undergraduates and the study and research of special topics of material mechanics for graduate students. This textbook is corresponding to and consistent with the contents of classical material mechanics, and basically covers all the problems involved in classical material mechanics-strength, stiffness, stability, dynamic response and advanced application of components. So this textbook is aimed at the whole material mechanics system, not just individual methods. I hope readers can realize that computer method is applicable to all problems in classical material mechanics, and its effectiveness is higher than that in classical material mechanics.

Maple Leaf Theoretical Mechanics I and Maple Leaf Theoretical Mechanics II

The 1 version of this book has been published for six years since 2006. The second edition has been further revised in the following aspects:

(1) absorbed the latest achievements of the "Teaching and Research" column of mechanics and practice, and 1 ~ the latest achievements of the 7th National College Mechanics Course Forum, and expanded it into one or two volumes, making this book complete in content, compact in structure, rigorous in narration and strong in logic.

(2) Based on calculus, linear algebra and probability theory, from simple to complex, from plane to space, the most distinctive basic contents of theoretical mechanics are emphatically introduced.

(3) Teaching statics, kinematics and dynamics with vector mechanics and analytical mechanics as the two main threads running through the whole course.

(4) Explain the basic concepts, formulas and methods from different angles, including strict proof, intuitive geometric explanation and physical explanation.

(5) Combining inheritance with innovation, the content of analyzing the whole process of sports is increased, and students are paid attention to mastering physical concepts through mathematical operations such as images and calculations. Through theoretical analysis and examples demonstration, students' thinking methods, mechanical simplification modeling ability, mathematical modeling ability, symbolic analytical calculation ability, numerical calculation ability, computer drawing and computer simulation ability are cultivated.

(6) Mechanical principles can be divided into invariants and variational principles. This textbook talks about invariants first, and then about variational principles. Invariants are as important as variational principles. This revision adds the content of variational principle to meet the engineering needs of the rapid development of science and technology.

(7) With the development of modern science and technology, the structures of various equipment systems are becoming increasingly complex, and the reliability of various systems such as satellites, rockets, airplanes, navigation systems, aircraft carriers, robots, high-rise buildings, long-span bridges and high-speed trains has been put on the research agenda. To improve the working reliability of the system, we can start from two aspects: First, improve the reliability of each component. The second is to study the best design, use and maintenance scheme of the system. In order to meet the needs of engineering, a chapter "Probability in Theoretical Mechanics" has been added to this textbook.

Winning record

In 2004, he won the second prize of scientific and technological progress in Shanxi Province;

In 2005, he was rated as an excellent teacher of mechanics teaching in China by chinese society of theoretical and applied mechanics.

In 2004, he won the second prize of teaching achievement of Hebei University of Technology;