Relationship between Applied Mechanical Stress and Space Charge Breakdown

Dielectrics may suffer various kinds of mechanical stress during the procedure of manufacture or application, and the mechanical stress has significant effect on the initiation of space charge breakdown. In this investigation, space charge is introduced into polymethyl methacrylate (PMMA) by electron beam irradiation, and the captured space charge can be triggered to detrap by needle tip or other mode of mechanical stress. The procedure of space charge detrapping can lead to space charge breakdown. The mechanism of space charge breakdown induced by applied mechanical stress was discussed. Many factors, such as space charge distribution in the samples, tensile or compressive mechanical stress, content of water in the samples that affected the space charge breakdown behavior induced by applied mechanical stress, were also discussed in this study