封隔器胶筒的非正态分布变量对其可靠性灵敏度的影响

Influence of Non-normal Distribution Variables on Reliability Sensitivity of Packer Rubber

针对工程实际中涉及非正态分布变量的封隔器胶筒密封不可靠问题,建立胶筒力学可靠性模型,提出Edgeworth级数和四阶矩的机械可靠性灵敏度数值分析方法;对密封胶筒力学模型的随机变量进行可靠性灵敏度对比分析,得出结构参数对封隔器胶筒可靠性的影响规律。结果表明:服从正态分布的几何尺寸比非正态分布的工作压差、密封载荷对封隔器胶筒可靠性的影响更显著,而非正态随机变量中,工作压差对胶筒密封可靠性的影响大于密封载荷的影响;随机方差灵敏度的增加,都会使胶筒趋向不可靠,但不同结构变量方差灵敏度的变化对胶筒密封可靠性的影响不尽相同。通过实例胶筒的可靠性灵敏度设计计算,验证该方法的有效性和准确性,工程应用中该方法可作为封隔器胶筒结构参数定量设计和可靠性设计的依据。

Aimed at the unreliable sealing problem of packer rubber with non normal distribution variables in the engineering practice,a mechanical reliability model of packer rubber was established,and a numerical analysis method of mechanical reliability sensitivity of Edgeworth series and fourth-order moment was proposed. The reliability sensitivity of the random variables of the sealant cylinder was compared and analyzed,and the influence of the change of the structural parameter design on the reliability of packer rubber was obtained.The results show that the influence of the physical dimension of normal distribution is more significant on the reliability of the packer than the working pressure difference and the sealing load of non-normal distribution. In non-normal random variables,the influence of working pressure difference on the sealing reliability of packers rubber is greater than that of sealing load.With the increase of the random variance sensitivity,the packer rubber tends to be unreliable,but the variation of the variance sensitivity of different structural variables has different effects on the reliability of the packer rubber seal.The validity and accuracy of the method were verified by designing the reliability sensitivity of the packer rubber.This method can be used as a basis for quantitative design of reliability evaluation indexes and structural parameters of packer rubber in engineering application.