Abstract:

Mechanism of axial dynamic buckling of thin-walled square was studied, and design method of axisymmetric deformation square was indicated, it was used mainly for design of energy-absorbing structures of subway anti-climbers. Dynamic load characteristics of axisymmetric dynamic buckling of thin-walled square were revealed, mathematical models of average impact force and plastic transverse, longitudinal waves were built, it was proposed that thin-walled square's deformation mode was decided by propagation velocity of the plastic stress wave and overall bending stiffness of thin-walled square, and it was explained that design of axisymmetric deformation square is easier than that of tube. Axisymmetric deformation square was designed according to certain safety requirements, energy-absorbing structures of anti-climbers can be designed in parallel by thin-walled squares of different thicknesses,materials and cross-sections. Mathematical models can guide design of square with axisymmetric deformation, can save a lot of manpowers, financial resources and time, and it has an important significance for engineering practice.

Key words: thin-walled square, axisymmetric dynamic buckling, average impact force, plastic stress wave, bending stiffness

摘要：

通过对薄壁方管轴向动力屈曲的作用机理进行研究,提出了轴对称变形方管的设计方法,主要用于地铁吸能防爬器吸能元件的设计。揭示了薄壁方管轴对称动力屈曲的动载荷特性,建立了平均撞击力和塑性横波、纵波传播速度的数学模型,指出薄壁方管的变形模式是由塑性应力波的传播速度和薄壁方管全长的弯曲刚度两者共同决定的,解释了轴对称变形方管较圆管易于设计的原因。设计了一定撞击力要求的轴对称变形薄壁方管,吸能防爬器上吸能元件可由不同壁厚、材料、截面的薄壁方管进行并联设计。建立的数学模型可以指导轴对称变形方管的设计,能节省大量的人力、财力和时间,对于工程实践具有重要指导意义。

关键词: 薄壁方管, 轴对称动力屈曲, 平均撞击力, 塑性应力波, 弯曲刚度