低合金钢靶板受尖头弹冲击的变形与断裂

Deformation and fracture of low alloy steel target under the impact of conical projectile

研究了低合金钢板在尖头弹冲击条件下的侵彻过程,讨论了应力条件和材料冶金质量对损伤和断裂的影响。结果表明,在侵彻过程前期靶材主要表现为三向压应力下的塑性流动;中期,靶材挤压流动,靶材内部的流速差造成剪切变形,并导致沿轧制偏析带的开裂;后期,靶材在剧烈剪切作用下剪切变形、局部失稳、形成剪切带和沿剪切带的开裂或撕裂。断裂按微孔聚集型机制进行。通常所谓花瓣型开裂实质上就是上述在切应力作用下的剪切撕裂。

Damage and fracture of a ductile steel plate penetrated by conical projectile have been studied in this paper. The results indicate that , in the early stage of penetration, the main response of the target is plastic flow on triaxial compressive stresses condition. In the medium stage, the target material flows under extrusion stresses, the shear strain is induced by differ-ences of flow velocity at different location and the shear cracking is generated along rolled segregation bands. In the later stage, the shear bands result from the local instability and the cracking or tearing along the shear band occurs successively by the action of severe shear. The damage and fracture in above mentioned processes proceed in accordance with mechanisms of microvoid nucleation, growth and coalescence.