高速细长杆侵彻失稳与断裂机理研究

With hydrostatic ultrasonic velocity, Hugoniot stress-strain relation and.Hugoniot sound velocity measurements and through data analysis，shook-compressed behavior of YB-AD90 is investigated. The material parameters relevant to Hugoniot elastic limit state are obtained. It is found that both Hugoniot stress-strain and.hydrostatic Hugoniot pressure-strain relations exhibit as typical elastic-plastic response and that YB-AD90 must be damaged and failed under shock compression. Therefore, the author proposed a constitutive model for YB-AD90 which includes the.equation of state, the damage evolution equation and transfer of energy loss duo to compressive damage. The model successfully reproduced the measured velocity histories from plate impact experiments for the ceramic. Through depth-of-penetration (DOP) experiment, recovery examination, It is found the ballistic performance（ in terms of differential efficiency factor c e . and Tate’ target resistance t R ） are.constantly degraded with increasing the thickness of YB-AD90 ceramic tiles until to a constant level, or in other words there exists an optimized thickness for the ceramictile design. It is pointed out that the macro-mechanical properties of ceramics such as shear strength, compressive strength et al play a significant role during the initial penetration while the flow properties of the pulverized ceramics govern penetration.resistance during the quasi-steady penetration. With the imaginary non-damaged hydrostatic Hugoniot and JH-2 constitutive relation, a series of two-dimensional numerical simulation were performed on the penetration of long-rods into ceramic targets. It is found that the experimental results are basically in accord with the simulations. Besides, the physical pictures during penetration process can illustratedcomparatively clearly.

内容：一是建立能正确反映细长杆侵彻失稳与断裂二者内在联系的力学模型；二是采用适当的数值方法求解该模型并给出杆侵彻失稳时的初速度和长径比之临界值及失稳后的断裂行为；三是进行细长杆侵彻靶板的实验研究，目的在于校核和完善所提的力学模型。.意义：阐明细长杆侵彻失稳与断裂的内在物理机制，从而为提高细长杆的侵彻效率提供理论依据。