多层过盈联接的可靠性稳健设计研究

Research on reliability-based robust design of multi-layer interference fit

基于厚壁圆筒理论,通过分析多层过盈联接的几何关系,推导得出结合压力与过盈量的矩阵表达式,明确了多层过盈联接力学模型的函数关系。以风电锁紧盘作为多层过盈联接的具体实例,根据应力-强度模型和失效机理,建立了锁紧盘可靠度数学模型,同时确定了锁紧盘可靠度相对基本随机变量的灵敏度;依据可靠度对基本随机变量灵敏度平方和最小原则及满足最小可靠度的原则,建立了风电锁紧盘可靠性稳健设计数学模型;为多层过盈联接过盈量的确定提供一种评价指标,进一步精确过盈量的具体取值。通过对设计参量的分析,确定摩擦因数、装配间隙、屈服强度对锁紧盘可靠度的影响。以某型号风电锁紧盘为例,对经典设计方法与可靠性稳健设计方法进行了比较。结果表明,基于可靠性稳健设计的锁紧盘,其可靠度提高了47.6%,且除屈服强度外,可靠度对随机变量的灵敏度均小于经典设计方法,稳健性更强。最后,通过试验验证了基于文中设计方法的锁紧盘能够满足实际运转过程中给定的工况要求。

Based on the theory of thick-walled cylinder,the matrix expression of combined stress and interference is derived based on the geometry relationship of multi-layer interference fit,and the functional relation of the mechanical model of multilayer interference fit is clarified.The wind turbine’s shrink disk is taken as a specific example of multi-layer interference fit.According to the stress-strength model and the failure mechanism,the mathematical model of the shrink disk’s reliability is established,and the sensitivity of the shrink disk’s reliability to basic random variables is determined.According to the minimum sum of squares of the sensitivity of shrink disk’s reliability to basic random variables and the minimum reliability,the mathematical model of reliability-based robust design is set up.This provides an evaluation index for determining the magnitude of multi-layer interference fit,and the specific magnitude of interference is accurate.The influences of the coefficient of friction,assembly clearance and yield strength to the shrink disk’s reliability are determined with the aid of design parameters.Taking a type of wind turbine’s shrink disk as an example,a comparison is conducted between the classical design and the reliabilitybased robust design.The results show that the shrink disk on the basis of reliability-based robust design improves the reliability by 47.6%;in addition to yield strength,the reliability-based sensitivity to random variables is less than that of the classical design,and the robustness is stronger.The experiment verifies that the method proposed in this paper can meet the specific requirements for the given working conditions in the actual operation process.