端头带有质量块的悬臂梁在冲击载荷下的两种剪切失效模型

剪切失效是强动载荷作用下结构失效的重要模式。本文给出了计及梁的转动惯量时端头带有质量块的悬臂梁结构受到冲击载荷作用后发生剪切失效的无量纲判据。分析表明，在初始速度间断面上是否发生剪切失效取决于质量块初始动能和质量块尺寸与梁厚之比，而与梁的长度无关。梁的转动惯量对于剪切失效具有不可忽略的影响。

Two Shear Failure Models of a Cantilever with an AttachedMass Block at the Tip under Impulsive Loading

The mention of different failure modes was firstly found by Menkes and Opat in 1973 on fullyclamped beams loaded impulsively. They reported that as the impulse increased, three distinctly differ-ent damage modes were noted :mode I: larse inelastie deformationmode II: tearing in outer fibres, at or over the supportmode III: transverse shear failure at the support.It has been shown from experimental investigations and theoretical research that shear failure isone of the important failure modes of structures under larse dynamic loading. This theoretical investi-gation examines the possibility of shear failure of a cantilever with an attached mass block at its tip un-der impulsive loading. This work can be considered as the continuity of a similar work by Professor YuTongxi in 1993. This paper analyzes the influence of the rotatory inertia of the cantilever on the shearfailure of the structure. A nondimensional kinetic energy criterion is presented for predicting the shearfailure at the interface between the mass block and the beam tip. It is illustrated that whether a shearfailure occurs at the interface , where the initial velocity has discontinuity , depends on the initial kinet-ic energy and the ratio of the size of the mass block to the thickness of the beam. It is also shown thatthe influence of the rotatory inertia of the cantilever on the shear failure is not negligible. The consid-eratin of the rotatory inertia of the cantilever increases the initial kinetic energy that the mass block ob-tains to cause the same shear failure at the interface. Comparison is also made between the case ofnotched cantilever and normal one.