水下爆炸球面冲击波作用下船体梁的刚塑性动响应特性

DYNAMIC RIGID-PLASTIC RESPONSE OF SHIP-LIKE BEAM SUBJECTED TO UNDERWATER SPHERICAL SHOCKWAVES

将船体整体结构简化为理想刚塑性等截面直梁,推导了梁上冲击波壁压的理论公式,并对其进行试验修正,给出了修正系数的经验公式。以炸药在船体中部正下方爆炸的工况为研究对象,提出了一种计算船体梁在球面冲击波作用下发生刚体运动或塑性运动的近似理论方法,并通过船体梁模型试验验证了理论方法的正确性,最后利用该理论方法深入讨论了船体梁的塑性运动特性。结果表明:在冲击波作用时间内,船体梁的塑性运动过程是在整体刚体运动的基础上叠加了一个塑性变形转动;相比减小爆距而言,通过增加药量来增大塑性变形的效果要偏小;就舰船整体结构安全而言,适当减小船长比增加船宽会有更好的抗冲击变形效果。

Firstly, warship’s hull was simplified as a rigid, perfectly plastic uniform beam floating on water, and the theoretical formula of wall-pressure on the wet surface of the beam was obtained. The formula was calibrated by test data of wall-pressure, thus an empirical formula for wall-pressure modification coefficient was presented. Secondly, to analyze dynamic responses of ship-like beam subjected to underwater explosion located closely under it at any stand-off, a theoretical method was provided to describe how the beam acts against blast as a rigid-body movement or plastic deformation. A ship-like beam was designed and experiments were carried out to verify the method’s correctness. Finally, more efforts were focused on the beam’s plastic deformation. The results show that beam’s plastic deformation under shockwave can be looked as a process of plastic rotation companied with a rigid-body movement. Shortening stand-off can increase plastic deformation more efficiently than adding explosives. For the sake of warship’s safety, shortening its length appropriately is more useful in resisting structural distortion than enlarging its width.