关于飞机结构疲劳载荷谱低载截除水平选取的探讨

Discussion on the determination of small-load truncation level of aircraft structural fatigue load spectrum

低载截除作为飞机结构疲劳载荷谱简化的重要内容之一,可以大幅节省疲劳试验的时间与成本,然而目前对于低载截除水平的选取尚无公认的标准方法。本文对文献中已有的低载截除水平进行广泛搜集,将低载截除水平划分为基于材料疲劳极限与基于谱最大载荷的两种选取方式,探究两种选取方式之间的联系,建立低载截除水平关系模型。结果表明:两种低载截除水平选取方式本质上是一致的,基于谱最大载荷的选取方式结合了飞机载荷与结构材料的特点,是对基于材料疲劳极限选取方式的延伸,所建立的低载截除水平关系模型能够为实际工程中疲劳载荷谱简化时低载截除水平的确定提供参考。

As an important part of the fatigue load spectrum simplification of aircraft structures,the small-load trun⁃cation can significantly save the time and cost of fatigue tests.However,there is no widely accepted standard meth⁃od for determining the small-load truncation level.In this paper,the existing small-load truncation levels in the lit⁃erature are collected and divided into two determination methods,which are based on the material fatigue limit and the spectral maximum load.The links between the two determination methods are explored.The relationship mod⁃el of the small-load truncation levels is established.The results show that the two methods are the same in essence,and the latter is an extension of the former combining the characteristics of aircraft loads and structural materials.The relationship model established between the small-load truncation levels could provide helpful references for the determination of the small-load truncation levels in the engineering fatigue load spectrum simplification.