铝合金/碳纤维混合前纵梁的轴向冲击吸能特性

Axial impact energy absorption characteristics of the aluminum/carbon fiber reinforced plastic hybrid front rail

为了揭示铝(Al)/碳纤维增强复合材料(CFRP)混合纵梁的吸能机制并提高其抗冲击性能,首先开展了空铝梁及内嵌碳纤维层合板的Al/CFRP混合纵梁动态轴向冲击实验,实验结果表明,相比于单一铝梁,Al/CFRP混合前纵梁的能量吸收W_(e)和比吸能W_(s)分别提高46.1%和17.5%。接着,采用MAT54材料模型,在LS-DYNA商用有限元软件中建立相应的有限元模型(FEM),并通过实验数据验证了模型的准确性,揭示了混合结构的能量提升机制及碳板的损伤模式,结果表明混合梁中铝梁和碳板的能量吸收分别比单一铝梁和碳板提高了30.7%和43.4%,混合梁的耗散能比单一组分的摩擦吸能之和提高了217.8%;利用理论模型预测了混合纵梁中铝梁、交互效应及整体的平均压溃反力P_(c),预测结果与仿真结果及实验结果均吻合较好。最后用有限元手段研究了铝梁壁厚、碳板厚度及碳板铺层角度对Al/CFRP混合结构的耐撞性影响,发现混合梁的能量吸收和峰值载荷随着铝梁厚度及碳板厚度的增加而提高。

To reveal energy absorption mechanism and improve crashworthiness of aluminum(Al)/carbon fiber reinforced plastic(CFRP) hybrid front rails, firstly, the dynamic axial impact tests of net aluminum rails and Al/CFRP hybrid rails with carbon fiber sheets embedded into aluminum hollow were carried out. The experimental results show that the energy absorption Wand special energy absorption Wof Al/CFRP hybrid rail are improved by 46.1% and 17.5% compared to the net aluminum rail. Next, the material model MAT54 was adopted to build the finite element model(FEM) in commercial software LS-DYNA and validated by the experimental data. The FEM was used to reveal the mechanism of improvement in energy absorption and the damage mode of the hybrid rail. The result indicates that the Wof aluminum rail and CFRP laminate in hybrid rail is improved by 30.7% and 43.4% compared to the net corresponding constituent, respectively, and the friction dissipation energy of hybrid rail is improved by 217.8% than that of the sum of single component. Further, a theoretical model is adopted to predict the mean crushing force Pgenerated by the aluminum rail, interactive effect and the overall hybrid rail, and the theoretical results are in good agreement with the numerical results and experimental results. Finally, parametric studies of aluminum wall thickness, CFRP laminate thickness and CFRP laminate stacking sequence on the crashworthiness were conducted by the FEM, and results show that the energy absorption and peak crushing force of hybrid rails increase with the increase of aluminum thickness and CFRP thickness.