VibrationThis refers to the periodic back-and-forth motion of a mechanical or structural system near its equilibrium position. This phenomenon is widely present in nature and the engineering field, such as the operating vibrations of household appliances, the bumpy rides of vehicles; in geological activities, similar periodic movements are referred to asVibrationFor instance, earthquakes and moonquakes.
The exploration of vibration phenomena dates back to ancient times. In China, as early as the 10th century BC, our ancestors utilized the principle of vibration to create instruments like the sheng; records of the relationship between pitch and vibration were already present in the "Guanzi" from the 5th century BC. Concurrently, the ancient Greek scholar Pythagoras, in the 6th century BC, studied the relationship between string vibration and pitch through experiments, proposing the laws of string length, tension, and frequency. These early studies mark the initial understanding of vibration phenomena by humans.
In the late 16th century, Italian scientist Galileo discovered through pendulum experiments that the period of small oscillations is independent of the amplitude, a property known as "isochronism." Subsequently, Dutch physicist Huygens built upon this and invented the pendulum clock, delving into the nonlinear characteristics of large amplitude swings. His work, "The Pendulum," became a significant milestone in vibration research. These endeavors marked the beginning of scientific quantitative research into vibration issues.
In the late 17th century, the establishment of Newtonian mechanics and calculus provided mathematical tools for vibration analysis. In the 18th century, scientists like Lagrange, Bernoulli, and Euler systematically studied the vibration patterns of discrete mass-spring systems and continuous elastic bodies (such as strings, beams, and rods), laying the foundation for linear vibration theory. Their work revealed the natural vibration modes of multi-degree-of-freedom systems and elucidated the physical mechanism of resonance.
In the late 19th century, with the advancement of industrial technology, issues of vibration in engineering structures such as machinery, ships, and bridges became increasingly prominent. The resulting fatigue damage and noise problems spurred scholars to delve deeper into the mechanisms of vibration. This era saw the development of various approximate analytical methods and experimental testing techniques. Entering the 20th century, vibration theory emerged as a core knowledge in the fields of mechanical and structural engineering, incorporated into the higher engineering education system, laying the foundation for the development of modern vibration control technology.
Vibration research has now expanded into cutting-edge fields such as nonlinear dynamics, active vibration reduction, and smart materials. Its applications span across a wide range of disciplines, including aerospace, precision instruments, and biology, continuously driving the advancement of engineering technology.
