# Mechanical Behaviors of Polymer-Based Composite Reinforcements within High-Field Pulsed Magnets

## TL;DR

This paper studies how polymer composites behave in ultra-high magnetic fields and identifies why magnet failures occur at their ends.

## Contribution

The first investigation of Zylon fiber-reinforced polymer mechanical behaviors in high-field pulsed magnets from a composite perspective.

## Key findings

- ZFRPs showed a 45% reduction in radial and axial stiffness under high magnetic fields.
- Failure in the inner magnet was primarily due to damage in the end ZFRPs.
- Transverse mechanical strength and axial Lorentz forces significantly affect magnet structural performance.

## Abstract

The development of pulsed magnets capable of generating magnetic fields exceeding 100 Tesla has been recognized as a crucial pursuit for advancing the scientific research on high magnetic fields. However, the operation of magnets at ultra-high magnetic fields often leads to accidental failures at their ends, necessitating a comprehensive exploration of the underlying mechanisms. To this end, this study investigates, for the first time, the mechanical behaviors of Zylon fiber-reinforced polymers (ZFRPs) within pulsed magnets from a composite perspective. The study begins with mechanical testing of ZFRPs, followed by the development of its constitutive model, which incorporates the plasticity and progressive damage. Subsequently, in-depth analyses are performed on a 95-T double-coil prototype that experienced a failure. The outcomes reveal a notable reduction of approximately 45% in both the radial and axial stiffness of ZFRPs, and the primary reason for the failure is traced to the damage incurred by the end ZFRPs of the inner magnet. The projected failure field closely aligns with the experiment. Additionally, two other magnet systems, achieving 90.6 T and 94.88 T, are analyzed. Finally, the discussion delves into the impact of transverse mechanical strength of the reinforcement and axial Lorentz forces on the structural performance of magnets.