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Penetration depth is the most important parameter in terminal ballistics. Here only the case of projectiles penetrating granular medium is considered. Laboratory and field tests have shown that projectile characteristics such as mass, size, and nose shape, and target characteristics such as strength and density determine the depth of penetration. Analyses of full flight data recorded by onboard data acquisition system (G-Rec) are presented. These tests have revealed very high decelerations at impact with extensive particle fracture along the path of the projectile. Particle size distribution analysis of the sample collected from the projectile tip shows two to three orders of magnitude reduction in size. For similar impact velocities and target densities, Poncelet's coefficient does not vary with tip shape. [ABSTRACT FROM AUTHOR]

Numerical simulations were carried out to study the ballistic resistance of double-layered metal plates subjected to normal impact by the ogive-nose projectiles. 12 mm thick Weldox 460E steel targets consisted of two 6 mm thick plates in contact were impacted by 20 mm diameter ogive-nose projectiles. The caliber radius head (CRH) of ogive-nose projectile was varied (0 - 5.0) and found to have obvious effect on the ballistic limit of 12 mm thick double-layered Weldox 460E steel plates. Double-layered plates were found to be less effective than the equivalent monolithic targets for CRH ≥ 0.5, and more effective with CRH = 0. LS-DYNA finite element code in conjunction with Johnson–Cook elasto-viscoplastic material model was employed to carry out the numerical simulations [ABSTRACT FROM AUTHOR]

Analyzing the response of modern mobile platforms to ballistic impact is a challenge due to target mobility and inherent structural loads. The present work involves an experimental and numerical analysis of ballistic impact against simulated moving targets that are pre-stressed. Realization of the target movement was achieved by launching an inclined elongated projectile at an oblique target, with equal inclination and obliquity resulting in an experimental set-up corresponding to normal impact of the target plate by the projectile with a transverse velocity component. The present experimental analysis considers impact by a 0.5" calibre projectile against the aluminium target, with the objective to analyze the target damage. The modelling results reasonably agree with the experiments. [ABSTRACT FROM AUTHOR]

The contribution describes the concept and numerical simulation of a ballistic protective layer which is able to actively resist projectiles or smaller colliding fragments flying at high speed. The principle of the layer was designed on the basis of the action/reaction system of reactive armour which is used for the protection of armoured vehicles. As the designed ballistic layer consists of steel plates simultaneously combined with explosive material - primary explosive and secondary explosive - the technique of coupling the Finite Element Method with Smoothed Particle Hydrodynamics was used for the simulations. Certain standard situations which the ballistic layer should resist were simulated. The contribution describes the principles for the successful execution of numerical simulations, their results, and an evaluation of the functionality of the ballistic layer. [ABSTRACT FROM AUTHOR]

We are developing a new diagnostic useful for the non-invasive detection of projectile passage in the launch tube of a gas gun. The sensing element consists of one or more turns of single-mode optical fiber that is epoxy-bonded around the external circumference of the launch tube. The hoop strain induced in the launch tube by the passage of the projectile causes a momentary expansion of the fiber loop. This transient change in path length is detected with high sensitivity using a fiber optic-based interferometer developed by the NSTec Special Technologies Laboratory. We have fielded this new diagnostic, along with fiber optic Bragg grating (FBG) strain gauges we previously used for this purpose, on a variety of gas guns used for shock compression studies at Los Alamos and Sandia National Laboratories.We anticipate that, when coupled with a broad-range analog demodulator circuit, the fiber optic interferometer will have improved dynamic range over that of the FBG strain gauge approach. Moreover, in contrast to the FBG strain gauge which is somewhat temperature sensitive, the interferometric approach requires no alignment immediately prior to the experiment and is therefore easier to implement. Both approaches provide early, pre-event signals useful for triggering high-latency diagnostics. [ABSTRACT FROM AUTHOR]

The investigation on free-surface impact of projectiles has last for more than one hundred years due to its noticeable significance on improving defensive weapon technology. Laboratory-scaled water entry experiments for trajectory stability had been performed with four kinds of projectiles at a speed range of 20~200 m/s. The nose shapes of the cylindrical projectiles were designed into flat, ogive, hemi-sphere and cone to make comparisons on the trajectory deviation when they were launched into water at a certain angle of 0~20°. Two high-speed cameras positioned orthogonal to each other and normal to the water tank were employed to capture the entire process of projectiles' penetration. From the experimental results, the consecutive images in two planes were presented to display the general process of the trajectory deviation. Compared with the effect of impact velocities and nose shape on trajectory deviation, it merited conclude that flat projectiles had a better trajectory stability, while ogival projectiles experienced the largest attitude change. The characteristics of pressure waves were also investigated. [ABSTRACT FROM AUTHOR]