摘要
本文研究介电材料内含空气圆孔在外加均匀电场作用下放电而引起的热应力。首先推导了圆孔放电前的临界电能,然后将复杂的放电效应简化为只存在热效应,并假设临界电能全部转化为热能且沿圆周均匀分布,计算了圆周附近的热应力。最后以聚乙烯材料作为算例,讨论了圆孔尺寸、材料常数等对热应力集中的影响,以及孔洞放电产生的径向应力和环向应力的变化规律。结果表明孔洞放电所引起的热应力集中以孔边的环向应力为主,而且材料放热系数越小,径向应力、环向应力集中程度越明显。
The thermal stress induced by partial discharges inside an air-containing cavity in an infinite dielectric material subjected to a remote uniform electric stress was studied. Based on the mechanism of partial discharge, the critical discharge energy of the cavity was derived, and then the thermal stress was calculated under the assumption that all the electric energy stored inside the cavity will completely be converted to thermal energy, which is uniformly distributed along the whole surface of the cavity. Finally, the polyethylene was chosen as a model material for the related numerical calculations to discuss the effect of the cavity size and material constants on thermal stress concentration, and to explore the variety of radial stress and hoop stress at the rim of cavity. It is found that the thermal stress concentration caused by cavity discharge dominates mainly the hoop component of stress, and moreover the smaller the exothermic coefficient, the greater the radial stress and hoop stress.
出处
《力学季刊》
CSCD
北大核心
2008年第2期218-223,共6页
Chinese Quarterly of Mechanics
关键词
孔洞缺陷
气体放电
热应力集中
circular hole
gas discharge
thermal stress concentration
