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以民机典型机身段客舱下部结构为研究对象,建立了结构坠撞有限元模型,利用LS-Dyna软件进行了结构能量吸收特性分析。基于吸能结构思想,以降低传递到客舱地板的加速度载荷为设计目标,提出了一种民用飞机客舱地板下部结构吸能设计方法。设计制造了全尺寸的吸能结构试件,并进行了垂直坠撞试验。为评估坠撞分析与试验的相关性,提出了一种基于能量的能量吸收特性评估方法。首先对预试验分析结果与试验结果进行了相关性分析,根据相关性分析结果对分析模型进行了修正。修正后坠撞分析结果与试验结果的相关性表明,乘员质心处的平均加速度响应峰值误差为16.44%,最大平均反弹速度误差为10.53%,修正后模型的总体刚度与实际结构一致,分析获得的结构总体变形模式与试验结果基本一致。但能量吸收时间和加速度峰值出现的时间与试验结果相比误差较大,表明结构连接失效等结构建模细节对计算结果有显著的影响。
Taking the typical structure of the fuselage section of the civil aircraft as the research object, a finite element model of the structure crashes was established, and the structural energy absorption characteristics were analyzed by LS-Dyna software. Based on the concept of energy-absorbing structure, aiming at reducing the acceleration load transmitted to the cabin floor, a design method of absorbing energy for the under-floor structure of cabin for civil aircraft was proposed. Design and manufacture of full-scale energy-absorbing structural specimens, and conducted a vertical impact test. To assess the correlation between the crash analysis and the experiment, a method of energy-based energy absorption assessment was proposed. Firstly, the correlation between pre-test analysis results and test results was analyzed, and the analysis model was modified according to the results of correlation analysis. The correlativity between the corrected crash test results and the experimental results shows that the average acceleration response peak value at the center of mass of the occupant is 16.44% and the maximum average error rate of the bounce speed is 10.53%. The corrected overall stiffness of the modified model is consistent with the actual structure. The overall structure deformation mode and the test results are basically the same. However, the energy absorption time and peak acceleration time are quite different from the experimental ones, which shows that the structural modeling details such as structural connection failure have a significant impact on the calculation results.