There are various uncertain factors in most practical engineering applications, such as input loads, structural sizes, manufacturing tolerance, and initial and boundary conditions. The interval method and grey number theory are common methods to deal with uncertainty. In this article, the interval truncation method and grey number theory are improved. And a mixed method is proposed to represent the confidence interval of output result based on the improved interval truncation method and improved grey number theory. The proposed methods’ feasibility is verified by a stepped bar; the methods are applied to the analysis of aircraft landing gear safety uncertainty.

在大多数实际工程应用中，存在各种不确定因素，例如输入负载，结构尺寸，制造公差以及初始和边界条件。区间法和灰数理论是处理不确定性的常用方法。在本文中，对间隔截断方法和灰度数理论进行了改进。在改进的区间截断法和改进的灰度数理论的基础上，提出了一种混合方法来表示输出结果的置信区间。所提出的方法的可行性通过阶梯状棒进行了验证；将该方法应用于飞机起落架安全不确定性分析。