在爆炸载荷作用下固支梁或筒形弯曲板的塑性动态断裂

本文运用刚塑性分析方法研究了在爆炸载荷作用下固支梁的全塑性动态断裂过程。在爆炸载荷作用下,固支梁将首先在固支端进入塑性变形,当固支端塑性铰转角达到其临界值,或固支端处初始裂纹尖端张开位移达到其临界值时(如果固支端有初始裂纹的话),固支端将产生开裂和裂纹扩展。本文解给出了在动态断裂过程中固支梁裂纹扩展长度、裂纹扩展速度以及梁的轴向约束力随时间变化的规律,并给出了不同载荷幅值下梁的启裂条件和止裂条件以及最终裂纹扩展长度和最大挠度。该分析解也适用于固支筒形弯曲板的断裂问题。

The Dynamic Plastic Fracture of a Clamped Beam or Cylindrical Bending Plate under the Explosion Loading

The dynamic plastic fracture response of a clamped beam or cylindrical bending plate made of "soft" material subjected to explosion loading is investigated by using the method of rigid-plastic modeling. Under the effect of the loading ,the clamped beam will enter into plastic deformation at the clamped ends firstly. When the plastic rotational angle at the ends of the beam is increased to a critical value,or the crack tip opening displacement is increased to a critical value, if there is an initial crack at the ends, then the crack will be produced in the clamped ends and the cracks will propagate. In this paper the formulations about the crack length,crack tip speed,bending moment and axialforce at the fracture section are determined as functions of time after crack initiation. Some significant results are given in this paper. The results can be applied to the facture of a clamped cylindrical bending plate.