摘要:长杆弹由于具有长径比大、侵彻力强等特点，因此长杆弹的侵彻机理的研究一直受到重视。为此，本文主要从以下几个方面对长杆弹侵彻半无限靶、有限厚靶及陶瓷/金属复合靶进行了研究和探讨：
   一.根据柱形空腔膨胀理论，采用统一强度理论作为材料的破坏准则，对于不可压缩材料，可压缩材料的弹性-塑性响应，弹性-裂纹-塑性响应求得了空腔膨胀压力。结果表明，在空腔膨胀率较低时，材料为弹性-裂纹-塑性响应，而在空腔膨胀率较高时，材料为弹性-塑性响应。
   二.根据所求出的空腔膨胀压力求出作用在弹体上的侵彻阻力，求出弹体以速度300m/s-1100m/s垂直侵彻半无限混凝土靶，分析了强度理论参数b、弹头形状、弹体密度等因素对侵彻深度的影响。
   三.利用统一强度理论求出了圆板的塑性极限统一解和混凝土板轴对称冲切极限并与试验资料和文献中的结果进行了比较，并将二者进行了比较，说明在相同的荷载半径作用下对于薄板，容易发生弯曲破坏，随着厚度的增加，圆板更容易发生冲切破坏。进而建立了中低速弹体撞击下预测厚混凝土板贯穿厚度的理论分析模型，分析计算结果表明所求出的混凝土板贯穿厚度与经验公式符合较好。
   四.基于静态球形空腔膨胀理论，考虑脆性材料在高速冲击作用下的破碎，求出了空腔膨胀压力，即靶体阻力R〓，为合理确定修正的流体动力学理论模型中靶体强度参数提供了合理的方法，求出的侵彻深度与试验结果符合较好。
   五.根据静态球形空腔膨胀理论求出了陶瓷/金属复合靶的靶体阻力，并分析陶瓷层厚度、金属背板厚度对靶体阻力的影响，为合理地选择陶瓷层和金属背板厚度，以达到最佳的抗弹效果和最小的重量提供理论依据。
   总之，研究弹体侵入问题对于防护结构的合理设计，提高高技术常规武器的攻击能力具有重要的意义。本文的研究结果在理论上具有合理性，对工程实际具有重要的指导意义。

 ABSTRACT
   The penetration problems of long-rods have been paid much attention to because of its large L/D and high penetration capacities. So, in this paper, the penetration of semi-infinite targets, immediate thick targets and ceramic/metal targets are discussed form the following aspects:
   (1) On the basis of cylindrical cavity expansion theory, the elastic-plastic response, elastic-cracked-plastic response of incompressive material and compressive materials are investigated and the cavity expansion pressure are obtained. The unified strength theory is adopted as the failure criterion of materials. It is shown that the target material is elastic-cracked-plastic response when the cavity expansion velocity is small, or it is elastic-plastic response.
   (2) The penetration resistances are obtained on the basis of the cavity expansion pressure described above. The penetration depth of semi-infinite concrete targets against long rod at velocity of 300-1100m/s are analyzed. The influences of factors such as strength theory coefficient b, the shape and the density of the projectile on the penetration depth are investigated.
   (3) The plastic limit load of circular plate and the ultimate punching capacities of concrete slabs are investigated with respect to the unified strength theory. The obtained results are checked by the experimental data and the exist results. The plastic limit load and the ultimate punching capacities are compared and it is shown that the bending failure will occur when the thickness of slab is very small, while the punching failure will occur with the thickness of slab increases. The penetration model of intermediate thick targets against intermediate velocity projectile impact is established and the present model predictions are compared with several empirical formulae and good agreement is obtained.
   (4) The target strength term R〓 in A-T model is derived based on the quasi-static spherically symmetric cavity expansion theory. The comminuted zone of brittle materials under high velocity impacting is considered in the model. The results of this model are compared with the test data and good agreement is obtained. So this provide a suitable method to determine the target strength term in the modified hydrodynamic model.
   (5) The target resistance of ceramic/metal target is obtained based on the spherical cavity expansion theory. The influences of the thickness of ceramic and the backed metal on the target resistance are analyzed. The theoretical basis is provided to suitable choose the thickness of the faced ceramic and backed metal in order to obtain the good resistant performance and minimum gravity.
   In general, the investigation of long-rod penetration problem is helpful for the suitable design of the defended structure and the improvement the efficiency of the projectiles. So, the work of this paper is of substantial significance to practical engineering.