Experimental Investigation On Application Of The Electric Pre-stress Effect In Engineering

Generally, the property of dielectrics will deteriorate and even breakdown under the action of the DC or AC electric field for some time. But recently, a lot of studies show that some properties of some dielectrics have strengthened after pre-treated in electric field before they are used. This pre-treatment of dielectric in electric field is named after the electric pre-stress treatment. After electric pre-stress treated, the change of dielectric property is named after the effect of electric pre-stress.The possibility of applying the electric pre-stress in some fields of engineering is studied through experiments in this paper. It is discovered that the diameters of silicon rubber decrease and the number of silicon rubber increase by the DC electric pre-stress applied during solidifying of silicon rubber-toughened epoxy resins. The effect is independent of the polarity of electric pre-stress, but it is dependent of the intensity of electric pre-stress.In addition, it is found that DC electric field weakens the effect of release agent and strengthens the binding strength between epoxy resins and anode in the condition of the existence of release agent. But this effect of electric field is not discovered between epoxy resins and cathode.In the study of the effect of electric field on the binding property of copper foil-covered veneer sheet, because of lack of experimental method and the complexity of the object studied, it is not found the regular effect of electric field on the binding strength between copper foil and veneer sheet or on the inter-laminar binding strength of veneer sheet. But it is further testified that DC electric field makes the free linkage generated during solidifying of epoxy resins orient along the direction of electric-power line. Theoretically, it is possible to accelerate water move from outside of cable to inside and therefore to accelerate the cross-linking reaction of silane-g-PE by gradient force of electric field when electric pre-stress is applied in the process of warm water cross-linking of silane-g-PE cable. In the paper it is discovered that it is necessary to design the suitable cable structure for the exertion of the effect of electric pre-stress in the process of warm water cross-linking of silane-g-PE.This paper offers some experimental foundation for the further study about the application of electric pre-stress in the engineering field.