A6061薄壁圆锥管轴向压缩性能的数值分析和理论研究

采用LS-DYNA软件对锥倾角0°~40°、壁厚1 ~2.5 mm的A6061圆锥管进行轴向压缩仿真，研究锥倾角和壁厚对圆锥管吸能特性和变形规律的影响；基于Mamalis圆锥管瞬时载荷压溃模型，提出大范围锥倾角（15°~40°）瞬时载荷修正公式。研究结果表明：变形模式的临界角为15°,当锥倾角小于等于15°时，变形模式为堆叠模式，当锥倾角大于15°时，变形模式转变为嵌套模式；平均载荷与比吸能均随着锥倾角的增大缓慢减小，而初始峰值载荷则大幅度减小；随着壁厚增大，压溃模式由钻石模式转变为环形对称模式，平均载荷、初始峰值载荷和比吸能均增大。基于仿真结果，采用皮尔逊相关系数分析法修正了Mamalis瞬时载荷公式，修正值与仿真值的最大误差小于10%，通过试验验证了修正公式的准确性。修正公式为揭示大范围锥倾角薄壁管压溃机理提供了理论依据。

Numerical Analysis and Theoretical Studies of Axial Compression Behavior of A6061 Thin-walled Conical Tubes

The axial compression simulation of conical tubes, which had cone inclination from 0° to 40° and wall thickness from 1mm to 2.5 mm, LS-DYNA software was applied to study the influences of cone inclination and wall thickness on the energy absorption characteristics and deformation law of conical tubes. In addition, the instantaneous load correction formula for the wide range of the cone inclination angle(15°~40°) was proposed based on the instantaneous load collapse model of Mamalis conical tube. The results show that the critical angle of the deformation mode is 15°, but the deformation mode is in the stacked mode when the cone inclination is less than 15° and it is in the nested mode when the angle is greater than 15°. Moreover, with the increase of the cone angle, the average load and the specific energy absorption decreases gently, while the initial peak load decreases significantly. It should be noted that with the increase of wall thickness, the crushing mode must transform from the diamond mode into the annular symmetry mode while the average load, the initial peak load and the specific energy absorption increase. The simulation results illustrate that the Mamalis instantaneous load formula is modified by the Pearson correlation coefficient analysis method and the maximum error is less than 10% between the modified value and the simulation value, In addition, the accuracy of the modified formula was verified by the experiments. In brief, the correction formula provides a theoretical basis for revealing the mechanism of crushing of thin-walled tubes with large-scale tapered inclination.