PROJECT TITLE:

Analysis of Cumulative Damage Failure for Driving Coil in Coilgun

ABSTRACT:

In the launching experiment of a coilgun, the driving coil, as well as winding and shielding, is always destroyed when several launching times. To boost the service life of a coilgun, the cumulative injury mechanism of the shielding and the fatigue life assessment of the winding are investigated in this paper. 1st, the electromagnetic field of a coilgun, considering the kinematic influence, is simulated using the sector–circuit time-stepping finite-part methodology. Afterward, the result of the electromagnetic force (EMF) is applied to the structural field as the load to calculate the stress and displacement distributions. Yet, using the static strength assessment, it's determined whether or not there's a defect within the materials. For the shielding created of a nonmetallic material, if the stress is greater than the final tensile strength (UTS), cracks must emerge. For the winding made of a metallic material, although the stress is but UTS, the fatigue failures still occur with the application of repetitive masses. The analysis results of the cumulative failure show that the shielding is destroyed when several launching times. In line with the stress–life characteristics (expressed as – curves) of the winding material and the analysis results of fatigue, the service life of the winding is a lot of longer than that of the shielding. Finally, a type of insulating material with higher UTS is proposed to improve the service life of the coilgun.