子母弹头螺开舱裂纹扩展机理研究

Study on Fracture Expansion of Nose Shell with Shrapnel Ejecting

根据断裂力学基本原理,尝试建立了裂纹扩展方向与材料微观组织参数之间的关系模型,旨在指导头螺新成形工艺的制定,在满足头螺开舱性能的前提下,大幅度提高材料利用率.对现行头螺及其破片进行了宏微观分析,发现开舱是一个裂纹动态扩展过程,主扩展方向与材料流线一致.通过考虑裂纹尖端的塑性区以及对扩展模型进行等效处理,建立了头螺壳体裂纹扩展模型及理论判据,认为当裂纹尖端纵向位移小于流线间距离时,裂纹能够沿某一流线方向进行稳定贯穿.模型计算结果与静爆实验结果相吻合表明,建立的裂纹扩展模型基本合理,可用于指导头螺新成形工艺的制定.

To guide the new process making of the nose shell and improve the utilization ratio of the material on the premise of meeting ejecting performance of the nose shell, the relation model between fracture expansion direction and material＇s microstructure factors was tried to be established on the basis of the fracture mechanics principle. After macro and micro analysis of the current product and its fragments, it is concluded that the smashing is a dynamic crack expansion course and the main expansion direction is consistent with flow lines. The theory criterion of the fracture expansion of the nose shell is established that the fracture can penetrate stably along some flow line while the vertical shift of the crack tip is less than the distance between the flow lines by considering the plastic area of crack tip and equivalent processing the fracture expansion model. The fact that the calculation results coincide well with the static explosion experimental results indicates the fracture expansion model is basically reasonable, which can be used to guide the new forming process.