自由梁中部在平头子弹横向正冲击下的穿透及变形

Perforation and Deformation of Free-free Beam byTransverse Impact of Flat nosed Missile at the Middle of Its Span

研究了均匀矩形截面自由梁中部在小尺寸、平头、刚性、圆柱形弹体正撞击下的变形及穿透过程。当子弹冲击速度接近或高于临界穿透速度时 ,在梁上与子弹接触区的周围会形成一个剪切冲塞 ,子弹通过冲塞作用在梁上的剪应力会引起梁的整体弯曲变形。通过动力分析 ,确定了子弹穿透梁的临界穿透速度。对子弹穿透梁的局部剪切过程和梁的各个变形阶段进行了数值计算 ,估算出局部剪切能、梁弯曲变形能。

An analysis is presented to model the perforation process of a rigid plastic free free beam with uniform rectangular cross section when it is struck normally by a small size flat nosed cylindrical missile at the middle of its span.At a speed above the ballistic limit,the missile generates a plug at the periphery of the contact region.The plug tends to separate from the beam,and transverse shear strain occurs in the area around the plug and the missile.At the same time,the shear force applying on the beam through the plug causes the beam to move in the impact direction with bending deformation.Numerical calculatins are made for several ratio of beam length to thickness.Above the ballistic limit,the residual kinetic energies of the beam and the missile,the energy dissipation due to bending of the beam and due to shear in the process of plug formation are estimated.