Impact resistance and encapsulating protection performance of epoxy resin based composite materials in embedded measurement instrument

The embedded measurement instruments (EMI) are widely used in dynamic information acquisition and target characteristic detection during target penetration process. The internal electronic in EMI are easy to be damaged by the strong overload and stress wave generated by the projectile-target interaction. Therefore it is necessary to improve the impact resistance of EMI by potting reinforcement. In this paper, resin matrix composites with varying contents of carboxylated-terminated liquid acrylonitrile rubber (CTBN) were prepared as encapsulating materials for EMI, and the high-g impact protection characteristics was evaluated. The overload resulting from projectiles penetrating typical hard targets was obtained through numerical simulation. Subsequently, the overload curve was decomposed and reconstructed using wavelet analysis to study the influence of excitation overload characteristics on the encapsulation protection performance. The effect of CTBN content on the mechanical properties was assessed through uniaxial compression tests under different strain rates. A nonlinear viscoelastic model (ZWT) was used to predict the mechanical behavior of encapsulation materials, and the corresponding LS-DYNA user-defined subroutine was developed. The effects of encapsulating material composition, loading conditions, and internal structure on the impact resistance of the core body under high-g conditions were further investigated. Results indicate that the peak stress on the chip can be effectively reduced by positioning the chip away from the center and utilizing high-strength encapsulating materials. By altering the installation position of the chip, the energy of most detail signals can be reduced, while the CTBN content of the encapsulating material only show significant influence in reducing the energy of detail signals within a specific frequency band.