Analysis of GFRP insulator characteristics under multiphysical fields in electromagnetic rail launchers

The glass fiber-reinforced polymer (GFRP) insulators in electromagnetic rail launchers (EMRLs) work in a complex environment coupling electromagnetic, thermal and structural fields. Ablation, metal deposition, fracture and other destructive forms easily appear in GFRP insulators, which will affect the efficiency and service life of the electromagnetic launcher system. To explore the factors causing insulator performance degradation, a coupling model of multiphysical fields, including electromagnetism, temperature and structure, was established to analyze the physical load on the GFRP insulators in EMRLs. And based on the results of the coupling numerical analysis, delamination or fracture may occur in the middle of insulators. An insulator sample was experimentally analyzed after electromagnetic launch tests to verify the simulation conclusions and to obtain the failure mechanism of GFRP insulators under extreme environments of multiphysical fields. During electromagnetic launching, the rails repeatedly compress the GFRP insulators and cause cracking of the GFRP insulators. High temperature causes carbonization and metal contamination on the surface of the GFRP insulators, which results in a decrease in surface resistivity. In addition, there were pits on the surface of the GFRP insulators, possibly due to the armature planing against the GFRP insulators during electromagnetic launching.