金属 / 聚氨酯波形发生器复合弹体冲击载荷特性及调控机制

Using projectile impact to simulate blast / shock loading is an effective laboratory-scale loading method which has attracted great attention. The quasi-static compressive loading-unloading experiments of PWGs with different geometric sizesaremade to investigate the impact load characteristics of metal / polyurethane waveform generator (PWG) composite projectile and the regulation effect of PWG on the load. The basic mechanical properties of PWG, including the qualitative relationship among the stiffness, energy dissipation ratio and the geometric size of PWG, are analyzed. Direct impact tests of metal / PWG composite projectiles with different PWG configurations are performed. Based on direct impact test results, the impact process of metal / PWG composite projectile is systematically analyzed, and the quantitative relationships among the characteristic parameters of impact load, the impact velocity and the PWG geometric size are established, respectively. The regulation effect of PWG stiffness on impact load is explored by the motion equation of single degree of freedom system for projectile direct impact test and the dynamic model of PWG. The results show that the static stiffness coefficient and energy dissipation ratio increase with the increase in diameter, but decrease with the thickness. The results show that the static stiffness coefficient of PWG increases with the diameter, but decreases with the increase in thickness. Compared with PWG diameter, the thickness shows more significant influence on the energy dissipation. The impact load characteristic parameters are significantly correlated with the product of diameter and thickness (D 伊 H) of PWG. With the increase in D 伊 H, the peak pressure decreases exponentially, and the duration and peak specific impulse increase nonlinearly in 2-order and 3-order, respectively. With the increase in the impact velocity, the peak pressure increases nonlinearly in 3-order, the peak specific impulse increases linearly, and the pulse duration decreases nonlinearly in 2-order. In addition, the influence of PWG diameter on impact load is mainly realized by regulating the linear static stiffness coefficient 琢. The larger the PWG diameter is,the larger the 琢 is, the smaller the peak load is, the greater the impulse is, and the more similar the load shape to half-sinusoid. The influence of PWG thickness on impact load is mainly realized by regulating the nonlinear static stiffness coefficient 酌. The smaller the PWG thickness is, the larger the peak load is, the smaller the impulseis, and the more obvious the shape of ‘peak and thin waist爷 is.