基于统计能量理论的飞行器壁板高频声振疲劳寿命预报及参数设计

SEA-BASED FATIGUE LIFE ESTIMATION ALGORITHM AND PARAMETERS DESIGN FOR VEHICLE-PLATES EXCITED BY HIGH FREQUENCY FLUCTUATIONS

  • 摘要: 为研究高速飞行器受高频脉动噪声载荷激励下的结构声疲劳问题,讨论了基于应力谱的频域疲劳损伤计算方法。该文提出了一种基于统计能量理论(SEA)的结构高频随机振动疲劳寿命计算方法。在该方法中,首先采用SEA计算子系统的均方应力,然后引入模态间隔的Rayleigh和Poisson分布假设,生成飞行器壁板的随机模态空间并构建危险点的应力谱曲线,进而结合频域疲劳寿命分析方法,采用Monte Carlo模拟求解壁板的疲劳寿命。验证分析表明,基于SEA和Monte Carlo模拟的结构高频声振疲劳寿命分析方法计算精度高,是高速飞行器强度设计的一种可靠方法。在此基础上,考察了壁板厚度和结构阻尼参数对壁板声振疲劳寿命的影响,计算结果表明,当输入声压谱一定时,存在局部最优解,采用该局部最优解作为壁板的设计参数可明显降低结构质量。

     

    Abstract: In order to study the fatigue life of high-speed vehicles excited by a turbulent boundary layer in a high-frequency band, frequency-domain fatigue damage estimation methods are discussed. A new method for the broad-band vibration fatigue life analysis based on statistical energy analysis(SEA) is approached. The principle of the method is to first calculate the mean square stress using SEA, and Poisson and Rayleigh distributions for resonance frequencies of the vehicle-plates are assumed to build the stress PSD curves of the dangerous point, then the fatigue life of the plate is analyzed using a Monte Carlo simulation. Verification shows that the method is accurate and feasible, and it is a reliable method for the strength design of high-speed vehicles. On this basis, the influence of structural damping and thickness on the fatigue life of the plate is discussed, the results show that a local optimal solution exists and structure weight can be reduced by using the local optimal solution as the design parameters of a vehicle-plate.

     

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