The invention discloses a beam damage identification method based on a Koopman auto-
encoder neural network, and the method comprises the steps: collecting the dynamic response data of a structure under the
impact load effect based on the
finite element simulation analysis of a
cantilever beam; then, the collected data is preprocessed, and a
data set used for training a Koopman auto-
encoder neural network is constructed; training a Koopman auto-
encoder neural network by using the
data set so as to learn a nonlinear evolution law of the beam structure power
system and obtain a linear lifting form of the beam structure power
system; and based on the trained network, calculating Koopman modals of a health state and a to-be-detected state, and constructing a damage index by comparing the difference between the health state and the to-be-detected state, thereby realizing accurate identification and positioning of the beam structure damage. According to the method, the characteristic that a
nonlinear system is globally linearized according to the Koopman theory is utilized, the defect that a traditional method is sensitive to structural nonlinearity and
environmental noise is overcome, and the method has the advantages of being high in recognition precision, high in anti-
noise capacity and the like and is suitable for beam
structure health monitoring under complex working conditions.