Research and Optimization on Crashworthiness of Self-similar Bionic Multi-cell Thin-walled Tube
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摘要: 仿生结构以其优异的力学性能被广泛的应用于各种机械结构中。为了提高薄壁结构的耐撞性,将结构仿生学概念引入其结构设计中,提出了一种新型的多胞薄壁吸能结构。采用了理论和数值模拟技术对0~2阶次层次截面的薄壁结构进行对比分析,结果表明:随着仿生层次结构的不断增加,仿生薄壁结构的吸能特性与变形模式进一步提升。同时,结合响应面法和遗传算法对2阶层次截面的薄壁结构进行了优化,并得到了相应的Pareto前沿图,为薄壁结构的耐撞性设计提供了新思路。Abstract: Bionic structure is widely used in various mechanical structures for its excellent mechanical properties. In order to improve the crashworthiness of thin-walled structures, the concept of structural bionics is introduced into the structural design, and a new multi-cell thin-walled energy absorbing structure is proposed. With the increase of biomimetic hierarchical structure, the energy absorption characteristics and deformation mode of bionic thin-walled structure are further improved. At the same time, the response surface method and genetic algorithm are combined to optimize the thin-walled structure with the second-order hierarchical cross-section, and the corresponding Pareto front diagram is obtained, which provides a new idea for the crashworthiness design of the thin-walled tube structure.
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表 1 有限元模型参数
模型参数 数值 材料密度 $\rho /({\text{kg} }\cdot { {\text{mm} }^{ - 1} })$ 2.7×10−6 泊松比 $\mu $ 0.3 弹性模量 E/MPa 68210 屈服应力/MPa 80 极限应力/MPa 173 网格尺寸/mm 2 表 2 各管的沙漏能
截面形状 沙漏能/J 内能/J 沙漏能与内能之比/% T0 2.19 3235.6 0.07 T1 13.12 13370.0 0.10 T2 15.79 22399.0 0.07 表 3 各管冲击力理论预测值与数值模拟值比较
截面形状 理论值/N 仿真值/N 相对误差/% T0 1.895×104 2.021×104 −6.23 T1 9.419×104 9.027×104 4.35 T2 1.451×105 1.503×105 −3.47 表 4 薄壁管的能量吸收
截面形状 内能/J 质量/kg 比吸能/(kJ·kg−1) T0 3235.6 0.3456 9.362 T1 13370.6 0.648 20.63 T2 22399.0 0.8208 27.29 表 5 样本数据统计
编号 D1/mm D2/mm t/mm ${F_{PCF}}$/N SEA
/(kJ·kg−1)1 22.00 19.37 1.684 133620.0 25.74 2 22.68 18.11 0.863 50400.0 17.42 3 23.37 9.89 1.747 129340.0 29.11 4 24.05 18.74 1.179 80945.0 20.44 5 24.74 12.42 1.621 123280.0 27.72 6 25.42 8.63 1.242 78086.0 21.68 7 26.11 14.95 1.305 93666.0 23.09 8 26.79 16.84 0.800 58959.0 15.34 9 27.47 15.58 1.432 110330.0 23.91 10 28.16 14.32 1.937 171240.0 30.46 11 28.84 17.47 1.874 170050.0 28.59 12 29.53 13.05 0.989 63369.0 18.67 13 30.21 8.00 1.368 95711.0 21.43 14 30.89 13.68 1.116 133620.0 19.72 15 31.58 11.79 1.558 50400.0 25.26 16 32.26 10.53 2.000 129340.0 27.84 17 32.95 11.16 1.053 80945.0 18.26 18 33.63 16.21 0.926 123280.0 16.76 19 34.32 20.00 1.495 78086.0 22.27 20 35.00 9.26 1.811 93666.0 24.57 表 6 响应面优化值与有限元仿真结果对比分析
参数 取值 /mm 目标参数 NSGA-Ⅱ算法优化 优化值 仿真值 误差/% D1 22.541 SEA/(kJ·kg−1) 29.075 28.93 0.50 D2 11.207 FPCF/N 123360 124040 −0.55 t 1.6901 -
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