A method and system for identifying full complex stiffness matrix of plant fiber reinforced composite material based on three-dimensional guided wave field

Abstract

The application discloses a kind of plant fiber reinforced composite based on three-dimensional waveguide wave field's full complex stiffness matrix identification method and system, comprising: narrow-band waveguide excitation is applied to sample and three-dimensional velocity time-domain response signal is collected;Signal is converted to polar coordinate system and modal separation is carried out;Real wave number-frequency pair representing dispersion characteristics and imaginary wave number-frequency pair representing attenuation characteristics are extracted respectively;Based on material structure parameter, establish stiffness matrix method forward wave propagation model and calculate theoretical complex wave number;Two-stage optimization objective function of real and imaginary wave number joint constraint is constructed, and full complex stiffness matrix is obtained by mixed optimization algorithm inversion.This application realizes the decoupling of geometric diffusion and material dissipation by multi-modal three-dimensional wave signal processing and complex wave number separation extraction;Combined with efficient forward model and global-local mixed optimization strategy, the stability and precision of high-dimensional parameter inversion are improved, which can be used for nondestructive testing and viscoelastic parameter accurate identification of plant fiber reinforced composite.

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