Vibration, or oscillation, is a periodic movement in time of a system around a certain equilibrium position. The system consists of at least an element for storing kinetic energy and one for storing potential energy. The vibration is a process of energy-type exchanges between the kinetic and potential energies. The equilibrium position is the state in which the potential energy becomes zero. The periodicity of the movement is described in frequency which is the measurement of the numbers of times the repeated events that occurred in a unit time. Vibration is an omnipresent type of
dynamic behavior of a system and exists in many forms, such as sound and music.
Human beings first recognized the vibration phenomenon by entertaining them?selves with percussion, string, and plate music instruments in ancient times. Just like the time when the lever principle was discovered is much later than that of its real utilization in human history, the time when the vibration and acoustics theory on the principles of the music instruments were discovered is much later than that of the music instruments were made and played. The earliest music instrument unearthed in Henan Province, China, is a bone flute, which can be traced back about 6000–5000 years B.C., while the earliest string vibration frequency and music acoustic theory for a string instrument ever written and published in Chinese history is around 700
B.C. in “Guanzi” by Guan Zhong (723–645 B.C.). In his music-scale algorithm, if the length of the basic string for the major tone is 1, the string lengths of the next scales are either added 1/3 (4/3) of the basic length or subtracted 1/3 (or 2/3), other music scales are determined by this 1/3 length rule, and he obtained five tones by this algorithm:
C, D, E, G, A. It’s amazing that more than 100 years later the Greek Philosopher and Mathematician Pythagoras (570–504 B.C.) discovered independently the very similar theory for seven tones: The Pythagorean scale.
Human beings first learned the vibration and acoustics of the plates and shells also from music instrument manufacturers. “Kaogongji” or “Artificer’s Record” 500 B.C. in Chinese history, recorded the Bian-Qing (sound bian-ching). It is a set of percussion, made of high-quality stones such as jade, with several fixed music scales.
The “Kaogongji” specifically described how to adjust the percussion music scale: “if music scale is higher, filing the surfaces of the plate, if the scale is lower, then filing the edges of the plate”. These technological processes, even though not giving exactly the quantitative relation between the natural frequencies of the plate and its geometrical parameters, are indeed in accordance qualitatively with the contemporary vibration and acoustic principles of the plate and shells: filing the surfaces of the plate makes the plate thinner and natural frequencies will be decreased while filing the edges of the plate makes the plate relatively thicker thus the natural frequencies will be increased.
One of the most important dynamic properties for the vibrations of a system is the inherit frequency or natural frequency. The vibrating movements of a system occur by external forces or internal self-excitement. When the frequencies of the excitation are the same or near the system’s natural frequencies, the responses of the systems will become larger and larger, which is called the resonance. The resonance has a variety of applications, such as radio, television, and music. The large-magnitude vibrations, such as large magnitude earthquakes, tsunamis, could bring harmful,devastative, and even catastrophic damages to properties and human lives. People tried to predict the earthquake by vibrating devices. In 132 A.D. Zhang Heng (78–
139 A.D.), a Chinese mathematician, an astronomer, and a geographer, invented the vibration utilization device: Seismographer. The shape of the device looks like a goblet. Eight (8) exquisitely casting dragons, upside down, attached to the body ofthe device. The eight dragons are mounted in the North, South, East, West, North?east, Southeast, Northwest, and Southwest directions, respectively, representing the earthquake directions. There is a ball in each dragon’s month. There is a vivid toad,mounted separately to the body, under each dragon. It is said that when an earth?quake occurs the dragon in the earthquake direction will release its ball in its mouth into the toad mouth as a prediction indication. The exact mechanism inside was not
well documented. It was recorded in history books that this device had successfully predicted an earthquake about 600 miles away in 138 A.D. just 1 year before he died.
In modern days, tens of thousands of types of vibrating machines and instruments have been successfully used to accomplish a variety of technological procedures in the fields of mining, metallurgy, coal mine, petro-chemistry industry, machine,
electricity, hydraulics and civil engineering, construction, railway, highway commu?nication, light industry, food and grain processing, biological industry, information technology, and process of human everyday life. The technologies involved in this science branch are so closely associated to agricultural and industrial production that it can create great economical and social benefits, and can provide great conve?nience and excellent service for people’s life. It becomes an inevitable means and a necessary mechanism for human production activities and life processes. A study of
“Vibration Utilization Engineering” as a new branch of science has been gradually formed and developed in the latter part of the twentieth century to cope with the increasing demands of the vibration utilization.
The literature on vibration utilization is scattered over all the magazines, books, journals, and conference proceedings in different academic fields and different science branches. It would be difficult to look into and collect the information and references on different vibrating machines. It would be informative and convenient to have an encyclopedia type of a book to cover as many types of vibrating machines and as many aspects of vibration utilization as possible and provide multi-sources and cross-references for scientists and engineers to use. This is part of our inten?tion in writing this book. The authors attempt to summarize the scientific research works on the vibration utilization over more than 30 years. The book also includes the following original and creative results led by the first author and Professor Bangchun
Wen and his team colleagues:
1. The authors constructed a theoretical framework for “Vibration Utilization Engineering”, this terminology is first both in domestic and international areas.
2. In the technological theory and technology creativities, the authors introduced the creative results obtained on technological theories and practical applica?tions in the Vibration Utilization Engineering such as Probability Iso-Thickness Screening theory; material sliding and throwing theory on different surfaces;and screening process theory and their applications in the vibration machine processes.
3. In mechanism creativities, the authors proposed a variety of new vibrating mech?anisms, such as exciter-eccentric type of self-synchronically vibrating mecha?nism, special forms of non-linear inertial resonant type of vibrating mechanism,etc., patent approved.
4. In the non-linear dynamic theory creativities, the authors summarized the
systematic studies and experiments conducted on vibration and wave utilization technology and equipment working theories and derived theory basis on many branches of the Vibration Utilization Engineering, such as vibration synchro?nization and application of the controlled synchronization theory, application of the non-linear vibration, etc. For example, the dynamic theory of a variety of vibrating machines and equipments, the equivalent mass and damping of vibrating machine systems, the theory and computing methods of the second vibration isolation of the vibrating machines and equipments, the vibrating synchronization theory and methods on duel- or multi-motor-driven vibrating machines, dynamic analysis, and dynamics parameter computation methods on non-linear vibrating machines, the dynamic design methods on vibrating machines and their main components, many of them are first published in this book.
5. In the design theory and method creativities, the authors proposed the systematic vibrating machine dynamic design theory and method, especially those for the non-linear vibrating machines and the comprehensive design methods which contain the dynamic optimization, intelligent optimization and visualization.
6. In the engineering applications, the authors have applied their theoretical results to engineering for over 30 years. For example, the inertia-resonance-probability screens, new mechanism type of vibrating cooling machines and new mech?anism type of vibrating crushers, etc. These machines are rewarded by the National Invention, National Technology Progress, etc.
商品简介
This book contains seven chapters. Chapter 1 introduces the formation and devel?opment of the Vibration Utilization Engineering; Chap. 2 devotes to some of the important research results in the vibration and waveenergy utilization in some technological processes; Chap. 3 describes the theories on the technological process of the vibration utilization technology and equipments; Chaps. 4 and 5 discuss the vibration utilizations of the linear, pseudo-linear, and non-linear systems; Chap. 6 presents the utilization of the wave and wave-energy; and Chap. 7 briefly illustrates the vibration phenomena and ut
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