Modal introduction
Modes are the natural vibration characteristics of structural systems. The free vibration of the linear system is decoupled into N orthogonal single-degree-of-freedom vibration systems, corresponding to the N modes of the system. Each mode has a specific natural frequency, damping ratio and mode shape. These modal parameters can be obtained by calculation or experimental analysis. Such a calculation or experimental analysis process is called modal analysis. Through structural modal analysis, the vibration characteristics of the mechanical structure in various order modes within a certain susceptible frequency range, as well as the mechanical structure in this frequency band and under the excitation of various internal or external vibration sources Vibration response results, and then obtain the modal parameters by the modal analysis method combined with related tests, with the help of these unique parameters for structural redesign.