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

Delamination failure analysis of G10 insulator in electromagnetic rail launcher

“…At 5.7 ms, when the armature exits the muzzle, the extrusion force of the armature on the rail is suddenly unloaded, the rail rapidly impacts the insulator under the action of the bolt pre‐tightening force, and the compressive load of the insulator increases rapidly, at which time the compressive strain is −0.71%. Then the current of the rail gradually decreases to 0, the insulator oscillates attenuatively, and finally converges to the initial pre‐tightening state [19].…”

“…The launch package (including the armature, projectile and bore riders) moves towards the muzzle under the action of EM force, and the containment is used to resist the EM repulsive force during launch. The material physical parameters are shown in Table 2 [19].…”

“…Scholars from the University of Texas at Austin [16,17] found that the insulator in the muzzle area delaminated after several tests, which became the starting point of failure and expanded in subsequent launches. Other scholars believed that the barrel dynamics, including the structural natural oscillation [18] as well as the repeated extrusion, friction [19] and deformation [20] of the rail, led to the cracking and delamination of G10 insulator. In summary, the current research on delamination damage of the insulator mainly focussed on the description and analysis of experimental phenomena, and scholars were generally concerned about the interaction between armature and rail during launch [21][22][23][24].…”

Third-Rail Insulator Failure Causes and Mitigating Practices: A Comparative Study of Multiple Case Studies in the U.S.

“…In step three, based on the KEQs, the data from selected case studies was collected and categorized by (1) transit system characteristics, (2) features of insulators, (3) insulator failure causes, (4) insulator failure costs, and (5) insulator failure mitigating practices. Subject matter experts (SMEs) from eight active transit agencies with third-rail systems were asked to Salt fog/air Schneider et al [36], Vohra [9] Snow and ice accumulation Vohra [9] Defective product/material Nyamupangedengu et al [22] Corrosion and fitting Venkatesulu [28], Luder et al [5] Damage from impact Jiang et al [24], Vohra [30] System voltage fluctuation Reddy [8], Vohra [9] Mechanical stress Nyamupangedengu et al [22] Flashover/arcing Verma and Reddy [6], Sun et al [14], Schneider et al [36], Chakraborty [37], Slama et al [19], Douar et al [20] Cracking/fracture Luder et al [5], Vohra [9] Dirt build-up Sun et al [14], Slama et al [19], Douar et al [20], Sima et al [21], Cavallin et al [23] Urban Rail Transit provide additional information for the data collection. Finally, the data was statistically and descriptively analyzed and compared through synthesis of similarities and differences.…”

“…Insulator corrosion is expected to occur inside tunnels, in locations where humidity/water exist [19]. The negative return current that is grounded by the rail is the major contributor to insulator corrosion [24]. Partial discharge, which occurs when insulators are exposed to high electric currents, is also an issue that can affect insulator performance [1,17].…”