不同轴截面薄壁筒在轴向冲击下吸能特性研究

Energy-Absorption Characteristics of Thin-Walled Tube with Different Axial-Section Shapes under Axial Impulsive Load

针对目前飞行器坠撞安全性问题研究,要减缓碰撞时的冲击载荷和耗散能量,以薄壁筒结构为研究对象,采用非线性有限元理论建立计算模型,采用显式动力学算法进行数值仿真。利用非线性有限元软件ABAQUS仿真了不同轴截面的薄壁筒在受轴向冲击下的变形,通过比较四种薄壁筒在受轴向冲击下的压溃力峰值、平均压溃力及比吸能研究其吸能特性,并与相关的理论解进行了对比。结果表明:冲击动能相同条件下,无论从比吸能方面还是从压溃力峰值方面来考虑,轴截面为梯形的薄壁筒的吸能特性优于轴截面为矩形的薄壁筒;从乘员的安全角度考虑圆台做吸能结构吸能是方台的1.5倍,而压溃力峰值只有方台的75.3%。

Aiming at the requirements of aircraft safety,the thin-walled tube structure under crushing force is studied in this paper.The finite element models of thin-walled tubes with different axial-section shapes between square and trapezoid are set up based on nonlinear finite element theory.Then,the dynamic explicit algorithm is adopted to simulate the impacting process.The deformation modes of thin-walled tubes with different axial-section shapes under axial impulsive load are investigated numerically using ABAQUS software.In order to study the energy-absorption characteristics,the peak value and the average of crushing forces of the four tubes are compared and the energy absorption capacity of the structure is studied extensively.Then,the numerical results are compared with the theoretic results.The results show that the energy-absorption characteristics of the tubes with trapezoid axial-section are superior to that of the tubes with rectangle axial-section.The specific energy-absorption capacity of cone tube is 1.5 times of frusta tube＇s,while the peak value of crushing force is 75.3 percent frusta tube＇s,which is more beneficial to the safety of the passengers.