Theoretical Study on the Temporary Cavity Caused by a High Speed Projectile When Wounding Living Organisms

Analyzes and calculates the process of development of a temporary cavity in the muscle directly after a projectile wounds organisms at a high speed. The muscle is taken as a non compressible Voigt Kelvin viscoelastic fluid model, on the assumption of moving in a radial direction and on spherical symmetry, a theoretical model proposed using the basic equations of the non Newtonian fluid mechanics. The model can well describe the pulsation process of the temporary cavity and changes of pressure in the cavity. The calculated results are in correspondence with the experimental results. The model can be applied in the quantitative analysis of a temporary cavity.

Dynamic response of armor-piercing bullets to blunt and penetration with protective gelatin

To investigate the coupled damage mechanism of blunt impact and bullets penetration after penetrating ballistic plates against human body targets,experiments were conducted using 6.8 mm caliber armor-piercing bullets against gelatin targets with protective coatings.A numerical analysis model was developed to simulate bullet penetration into gelatin with protective coatings,obtaining endpoint characteristic quantities such as bullet velocity changes,changes in energy distribution,pressure,stress,and stress wave variations within the gelatin target after protection.The results indicate that at a velocity of 640 m·s^(-1),the 6.8 mm caliber armor-piercing round failed to penetrate the ballistic plate yet still caused a blunt impact depression of 37 mm in depth.Under conditions where the bullet did not penetrate the ballistic plate,approximately 80%of the bullet's kinetic energy was absorbed by the ballistic plate.At a velocity of 740 m·s^(-1),the bullet penetrated the ballistic plate,resulting in a blunt impact depression depth of 56 mm and an instantaneous cavity with a maximum diameter of 60 mm.During the process of penetrating the ballistic plate,approximately 50%of the bullet's kinetic energy was absorbed by the ballistic plate,and about 40%of the remaining kinetic energy transferred into the gelatin during the penetration of the target.

Effect of rifle bullet parameters on the penetration into ballistic gelatin

To understand the effects of the rifle bullet parameters on the bullet-gelatin interaction quantitatively, a finite element model of bullet penetrating gelatin was set up and computational re- suits are compared with experimental ones. The penetration of the rifle bullet into the gelatin was simulated by the nonlinear finite element method. The quantitative analysis of the changes in the ge- latin interaction with the rifle bullet were conducted by changing the bullet parameters, such as at- tack angle on gelatin, initial velocity, warhead＇ s tip and location of mass center of bullet. Results demonstrate that with the increase of the attack angle, instable moment of the bullet moves forward, the length of narrow wound channel shortens, and when penetration is completed diameters of tem- porary cavities increase, the gelatin energy and energy transmission ratio increases; With the in- crease of the impact velocity, instable moment of the bullet moves forward, the maximum forces acting on the gelatin and the gelatin energy increase remarkably ; the length of narrow wound channel shortens, diameters of temporary cavities increase when penetration is completed, the gelatin energy and energy transmission ratio increase; The warhead＇ s tip and location of mass center have a influ- ence on the instable moment of the bullet and length of the narrow wound channel. The instable mo- ment delays and narrow wound channel increases when the warhead＇s tip flattens. The instable mo- ment moves forward a little and the narrow wound channel shortens a little when location of mass center moves back.