September 19, 2025Open Access

Research on the Influence Mechanism of Different Flight Altitudes on the Insulation Breakdown Performance of ETFE Aviation Cables

Key Points

Insulation breakdown strength of ETFE decreases significantly with increasing flight altitude, highlighting key performance concerns.
Molecular dynamics simulations indicated a 17.626% reduction in breakdown field strength at higher altitudes and with decreasing pressure.
Low-pressure breakdown experiments confirmed a 40.078% decrease in breakdown strength, emphasizing the material's vulnerability under these conditions.
Findings suggest that increased free volume and decreased air density at high altitudes weaken ETFE insulation, guiding future aerospace applications.

Abstract

By studying the breakdown performance of ethylene-tetrafluoroethylene copolymer (ETFE) under low pressure via molecular dynamics simulations, and verifying the simulation results through low-pressure breakdown experiments, the insulation failure mechanism of ETFE materials under low pressure can be revealed at the atomic scale. First, molecular dynamics simulations were performed on ETFE. As the flight altitude gradually increased from 0 km to 24 km, the simulated pressure decreased from 101.300 kPa to 2.951 kPa. Correspondingly, the intermolecular distance increased by 9.692%, the interchain interaction energy decreased by 8.383%, the free volume fraction of ETFE increased by 65.000%, and the density of ETFE decreased by 7.737%.Subsequently, based on the electromechanical breakdown theory, it was deduced that the breakdown field strength of ETFE decreased by 17.626%.Finally, the low-pressure breakdown experiment showed that the breakdown field strength decreased by 40.078%, and the density measurement test indicated that the density decreased by 1.574%. Both simulation and experimental results confirm that the breakdown field strength of ETFE decreases with the reduction of pressure. This is because under low-pressure conditions, the increase in free volume fraction and the decrease in air density provide a longer mean free path for free electrons; the decrease in Young's modulus leads to greater deformation under the same voltage, resulting in a higher applied field strength; and the decrease in charge trap level weakens the charge trapping capability, leading to a higher concentration of free electrons. All these factors contribute to the reduction of the breakdown field strength of ETFE. This study provides performance prediction and failure mechanism analysis for the application of ETFE in aerospace and extreme environments at high flight altitudes, and has guiding significance for the optimization design of aerospace insulating ETFE materials.

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Cite This Study

Li et al. (Wed,) studied this question.

synapsesocial.com/papers/68d466a831b076d99fa650a3 https://doi.org/https://doi.org/10.7498/aps.74.20250932

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