Resonance refers to the case where the natural frequency overlaps with the forced frequency (machine rotation, fluid generation, electricity generation frequency, etc.) and the amplitude rises. this is not This is an important design factor that applies not only to safety issues, but also to product quality and the lifespan of machines or structures.
Natural frequency calculation method
First, as a method to find out the natural frequency, there are a method by sweep excitation with a sine wave and a method for broadband excitation using an impulse frequency. In reality, the method using a time-frequency graph (Waterfall) by increasing the speed (RPM) of the machine, the method by impact test, and the calculation method by computer simulation (FEM) are widely used. Of course, the analysis by experiment is more accurate and takes precedence over the simulation analysis. Simulation analysis is mainly used when experiments cannot be performed (when the object is large), and it is a very appropriate method for design modification work based on experimentation. The application methods to find the natural frequency are summarized as follows.
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