(1. 北京航空航天大学 固体力学研究所, 北京 100083;
2. 中南大学 资环建学院， 长沙 410083)
摘 要: 剪切失效是强动载荷作用下结构失效的重要模式。着重研究了自由梁在中点受到质量块撞击后的剪切效应，给出了发生剪切失效的无量纲判据。分析表明，在初始速度的间断界面上是否发生剪切失效取决于质量块无量纲初始动能、质量比及梁的无量纲厚度。
关键字: 自由梁； 撞击； 剪切失效
by projectile at mid-span
（1. Solid Mechanics Research Center，
Beijing University of Aeronautics and Astronautics，Beijing 100083，P.R.China;
2. College of Resources，Environment and Civil Engineering，
Central South University，Changsha 410083, P.R.China）
Abstract:Shear failure is an important mode of dynamic failure of structural members under impulsive loading. Shear effect of a free-free beam subjected to impact by a projectle at the mid-span was studied and the non-dimensional criterion of the shear failure was presented. It was illustrated that whether a shear failure occurs at the interface，where the initial velocity has discontinuity，depends on the initial kinetic energy of the projectile，the mass ratio and the non-dimensional thickness of the beam.
Key words: free-free beam； impact； shear effect
