泡沫铝填充分体式翻转结构设计与优化分析

Structural Design Optimization of Split Typed Flip Tubes Filled with Aluminum Foam

汽车发生正面碰撞时,主要依靠汽车吸能盒和保险杠来吸收与传递碰撞能,因此性能优良的吸能盒结构能有效地提高汽车安全性。薄壁翻转管在受压翻转时,表现出较低的平均载荷力与较低载荷峰值,适合用作汽车吸能盒结构。但由于结构翻转过程复杂,在翻转过程中容易引发倾斜,出现不稳定状态,从而导致结构出现刚度变大而失去吸能效能。在对翻转管吸能特性与泡沫铝缓冲吸能效果研究的基础上,设计了泡沫铝填充分体式翻转管吸能盒,对比分析在填充泡沫铝前后的翻转管结构在有效行程内的稳定性与吸能量情况。结果表明,泡沫铝填充式翻转吸能盒不仅在吸收能量上得到大幅提升,其稳定性也得到较大改善,使汽车吸能盒在受到一定倾斜角度压溃时,在有效压缩行程内具备了较好的稳定吸能特性。通过采用NSGA-II算法对结构进行多目标优化分析,最终获得优化设计方案。

In a car frontal impact, the crash box and bumper act as a buffer to first absorb a portion of the impact energy and then transfer the remaining downward to the body structure, while the structures enabling the optimal energy absorbing capacity to advance the frontal crashworthy safety are concerned. Thin-walled flip tubes implement energy absorption under compressive loading by the flipping process with lower averaged and peak forces, whichis expected to benefit buffering impact. However, the kinetic complexity in flipping process is likely to cause structure tilting overleadingincreasing structural stiffness and instability to fail its expected energy absorption quality. As stable flipping concerned, based on the study of the energy absorption characteristics of multiple flip structures and aluminum foam, a split flip tube structure filled with aluminum foam is presented. The comparative studies of the stability and energy absorption effects for the structures with or without foam cores are carried out. The result shows that the aluminum foam-filled flip tubes have much improved effects in both stability and energy absorption, while the application simulations express that using them as the car energy-absorbing boxes has the same good properties, especially by the worst cases of impacting with tilting angles.Finally, design optimization for the structural parameters is obtained by the NSGA-II algorithm.