A method for identifying parameters of a resonant
fatigue crack propagation test vibration
system based on a
soft sensing technology comprises the following steps: 1, establishing a
system three-degree-of-freedom vibration mechanical model to obtain a kinetic equation, and deriving to obtain a
system frequency equation about a relationship among the system inherent frequency, the spring rigidity and the
particle mass; 2, calculating according to a finite element technology to obtain the rigidity of a test piece under different crack lengths, and testing the system resonant frequency when a crack is propagated to different lengths; 3, substituting the system resonant frequency value and the corresponding test piece rigidity under different crack lengths into the system frequency equation in order to obtain overdetermined equations about the
mass to be identified and unknown rigidity; 4, solving the overdetermined equations through a
least squares technique to obtain nonlinear equations about the
mass and rigidity; and 5, solving the nonlinear equations by using a Newton-Raphson formula, and identifying the vibration
system parameters comprising the
mass and the rigidity. The method has the advantages of good maneuverability, low cost and good accuracy.