复合绝缘子伞裙护套材料耐冲击力学特性研究

Research on Impact⁃resistance Mechanical Characteristics of Shed Sheath Material of Composite Insulator

鸟啄复合绝缘子为输电线路的安全运行带来了严重的隐患。为进一步理解材料特性与鸟啄损伤程度之间的关系,文中基于冲击动力学理论,对复合绝缘子的伞裙护套材料的耐冲击力学特性进行了研究。建立了包含材料弹性模量、密度、泊松比、鸟嘴形状系数等相关参数的复合绝缘子鸟啄冲击模型。模型根据鸟啄速度分为弹性变形、塑性变形与流体变形3个阶段,描述了复合绝缘子伞套材料的鸟啄深度与鸟啄速度之间的关系。设计了模拟鸟啄的人工冲击试验,以硅橡胶与脂环族环氧树脂两种伞套材料为例,对比了两种材料的耐冲击特性。结果发现,硅橡胶伞套材料随冲击高度的增加,经历了弹性变形至塑性变形阶段。鸟啄冲击模型可以很好的描述硅橡胶材料所受冲击速度与冲击深度之间的关系。脂环族环氧树脂材料的冲击过程同样存在弹性、塑性变形阶段,但最终以裂纹扩展断裂形式开裂,与鸟啄冲击模型中侵入深度逐渐增加最终贯穿的过程不符,因此不适合该模型。相较于硅橡胶材料,脂环族环氧树脂伞套材料具有更好的耐冲击力学特性,更能抵御鸟啄侵害。

Bird pecking composite insulator brings serious hidden danger to the safe operation of transmission line.For understanding the relationship between the material characteristic and the extent of bird pecking,the impact⁃re⁃sistance mechanical characteristic of the shed sheath material of the composite insulator is studied on the basis of the theory of impact dynamics.A bird pecking impact model of composite insulator,including such related parame⁃ters as elastic modulus,density,Poisson’s ratio,beak shape coefficient etc,is set up.According to the pecking ve⁃locity,the model can be divided into such three stages as elastic deformation,plastic deformation and fluid deforma⁃tion,and the relationship between the bird pecking depth and velocity of the shed material of the composite insulator is described.An artificial impact test simuating bird peck is designed.And such two types of shed material as sili⁃cone rubber and cycloaliphatic epoxy resin are taken as an example to compare the impact⁃resistance characteristic of the two kinds of material.It is found by the result that the silicon rubber shed material,with the increase of impact height,experiences the stages from elastic deformation to plastic deformation.The bird pecking impact model can de⁃scribe the relationship between impact velocity and impact depth of silicone rubber very well.The impact process of cycloaliphatic epoxy resin also has elastic and plastic deformation stages,but it is,as a result,broken in the form of crack development,and is not consistent with the penetration formed by the gradual increase of the penetration depth in the model,so it is not suitable for this mode.The cycloaliphatic epoxy resin,compared with silicone rubber,has a better impact⁃resistance characteristic and is more resistant to bird pecking.