Electromagnetically Driven Expanding Ring Test for the Strength Study of the Zylon/Epoxy Composite

An improved electromagnetically launched method for driving specimens of composite materials is developed. The electromagnetic expansion ring device consists of a solenoid and sample rings. The solenoid is made up of eight layers of copper wire reinforced with Zylon fiber, which can produce magnetic field up to 35 T. The sample ring is composed of a high-conductivity driver (6061-T6 aluminum ring) and a layer of Zylon/epoxy composite that is directly wound on the driver. The solenoid driven by a 100-kJ (25 kV, 320
$\mu\text{F}$
) capacitor bank is designed for inducing a pulsed current in the aluminum driver. Consequently, the induced current interacts with the axial magnetic field at the center plane of the solenoid to produce a large, uniform, and outward electromagnetic force. The Zylon/epoxy composite specimen is thus pushed outward by the aluminum driver. By adjusting the charging voltage of the capacitor bank, the force can be adjusted, and thus, the strength of the sample can be easily found by exploding the rings. Different thickness values of the sample rings with an aluminum driver have been tested. The strength is calculated to be around 5.2 GPa by means of finite element analysis.