Firstly, the structure is artificially excited in a static state, and the mechanical admittance function (transfer function) between any two points is obtained by measuring the excitation force and response and performing two-channel fast Fourier transform (FFT) analysis. .
Using the modal analysis theory, the modal parameters of the structure are identified by the curve fitting of the experimental admittance function, and the modal model of the structure is established.
According to the principle of modal superposition, the response history or response spectrum of the actual vibration of the structure can be predicted with various load time history known.
Sensor: Acceleration sensor
Excitation equipment: hammer or exciter
Data acquisition hardware: simultaneous acquisition of multi-channel vibration signals
Software: Modal Analysis Software
White body modal test:
A plurality of accelerometers are arranged on the surface of the body-in-white, and the modal experiment is performed by means of hammer excitation or exciter excitation. The data acquisition adopts NI PXI system and uses modal analysis software. The resonance frequency, damping and vibration mode of the vehicle body in the free state can be obtained through experiments.