飞机撞击荷载计算模型中压溃力选取分析

CRUSHING FORCE ANALYSIS OF A LOAD CALCULATION MODEL FOR AIRCRAFT IMPACT

Riera提出的飞机撞击荷载计算模型是一种比较实用的简化模型,大多数研究在进行飞机撞击试验和数值模拟时通常会把试验结果和数值模拟结果与该模型的计算结果进行对比分析。通过介绍分析Riera模型,该模型中撞击荷载包括压溃力和惯性力两部分,因此模型的使用需要确定压溃力大小。为了合理使用Riera模型,梳理了现有压溃力计算公式,各公式给出的压溃力计算结果差别较大,并通过公式推导预测弹体的变形长度和撞击作用时间与试验数据进行对比分析,评价了现有压溃力计算公式,对更适宜于飞机撞击条件下的压溃力计算公式给出了说明,最后讨论了压溃力对撞击荷载曲线的影响,得出压溃力相对于惯性力不能被忽略,对撞击荷载影响较大的结论。

The Riera model is a simplified practical model for the calculation of aircraft impact load. The results of aircraft impact tests and numerical simulations are usually compared with the calculation results of this model in many studies. Since an impact load consists of a crushing force and an inertial force by introducing and analyzing this model, the crushing force is needed to be determined. In order to use the Riera model more reasonably, the existing formulas for crushing force calculations are summarized, but there is a great difference in the calculation results of crushing forces by using these formulas. And the comparison between the test data and calculation results by deformed length and impact time of projectile is also made to assess these formulas for crushing forces. The formulas, which are more suitable for crushing force calculation in aircraft impact cases, are given and the influence of crushing forces on impact loads is discussed. The crushing force should not be ignored with respect to inertial forces and it has a big influence on impact loads.