高超声速飞行器的非概率可靠性分析

Non-probabilistic reliability analysis of hypersonic vehicle

摘要:

为探究高超声速飞行器整体结构可靠性及其可靠性的影响因素,确保飞行器执行任务时的结构安全,将应力-强度干涉模型与区间数相结合,提出了子域子区间新方法分析高超声速飞行器结构强度可靠性。首先,分析高超声速飞行器在不同飞行状态下各受力面的力矩；其次,将飞行器结构近似为等效悬臂梁,考虑其所受力矩、宽度和飞行高度的不确定性,并表示为区间数；然后,考虑飞行器结构强度随时间退化,基于应力-强度干涉模型进行非概率可靠性分析,建立飞行器结构动态可靠性模型；最后,提出子域子区间法分析结构强度的指数退化特性和飞行动态对结构可靠性的影响。仿真结果表明,子域子区间法相比于传统蒙特卡罗法,在相同采样点数情况下,精确度会更高,验证了所提方法的可行性和有效性；飞行器可靠性随着飞行器结构强度指数递减而逐渐减小；飞行器的飞行动态会对结构可靠性产生主要影响,其中随着飞行高度的升高飞行器可靠性会逐渐增加,随着速度以及迎角的增大而逐渐减小。

Abstract:

To explore the overall structural reliability of hypersonic vehicles and its influencing factors, and ensure the structural safety of the vehicles when performing missions, a new subdomain subinterval method for analyzing the structural strength reliability of hypersonic vehicles is proposed by combining the stress-strength interference model with the interval number. Firstly, the moment of each force surface of a hypersonic vehicle under different flight conditions is analyzed. Secondly, the vehicles structure is approximated as an equivalent cantilever beam, considering the uncertainties of its moment, width and height, which are expressed as interval numbers. Then, considering the degradation of the structural strength over time, a non-probabilistic reliability analysis is carried out based on the stress-strength interference model, and a dynamic reliability model of the vehicles structure is established. Finally, a new sub-domain sub-interval method is proposed to analyze the exponential degradation characteristics of the structural strength and the impacts of the flight dynamics on the structural reliability. The simulation results show that the subdomain subinterval method is more accurate than the traditional Monte Carlo method with the same number of sampling points, which verifies the feasibility and validity of the proposed method. The reliability of the vehicle decreases gradually with the exponential degradation of the structural strength of the vehicle. In addition, the flight dynamics of the vehicle has a major impact on the structural reliability, in which the reliability of the vehicle increases with the increase of the height of flight, and decreases with the increase of the velocity as well as the angle of attack.