What Is Random Vibration?
Random vibration refers to those vibrations that cannot be described by a deterministic function, but have certain statistical laws. For example, bumps during vehicle travel, structural response to gusts, bulkhead chatter caused by jet noise, and vibrations occurring on offshore drilling platforms, and so on.
Right!
- Random vibration is usually described using a probabilistic approach. Probability reflects the probability of a random event. The result of a random event is described in terms of quantity, and the concept of a random variable is derived. Because it describes the development process of a random variable, it is also called a random process, and random vibration is just a type of instance of a random process.
- Assume that a certain random test (such as a car road test) is repeated under certain conditions, and a series of time-varying history records of the system response (such as the vertical acceleration of the driver's seat) are obtained (see the figure). Each record
- There are two main aspects:
- Excitation-response relationship As mentioned earlier, the excitation-response relationship in random vibration problems can only be described as the relationship between their statistical characteristics. A linear system with constant coefficients produces a stationary random response Y under the action of stationary random excitation X. At this time, there is the following relationship about the average value: