A Particle Coupling Finite Element Method for Shock-Mitigation Characterization of Magnetic Granular Systems

Granular chain system could realize the impulse protection mechanism. This work presents the shock mitigation characteristics of magnetic granular chains in different configurations. Based on magneto-structural coupling algorithm, a particle coupling finite element method is proposed. The coupling process is to numerically capture the process of the pre-compression and magnetic force of each grain in magnetic analysis and the field-induced dynamic responses under impulse loadings. For validation, an experimental set-up is designed, and the experimental results are tested and compared. The numerical predicted values present a good agreement with experimental results. It is shown that, when the characteristics of peak force, peak velocity, incident kinetic energy and stress wave propagation are compared, the performance in interstitial decorated chains is superior and followed by reverse-interstitial decorated chains and then monodisperse chain. The increment of magnetic field strength enhances the field-induced pre-compression, magnetic force, and shock mitigation capacity of granular chains. Such nonlinear behavior of magnetic granular chains can be exploited in order to design new tunable devise, such as shock absorbers and impulse protector.