Missile Penetration Research Articles

MATERIAL CHARACTERIZATION BY AN INNOVATIVE BIAXIAL SHEAR EXPERIMENT AT VERY LARGE STRAINS AND AT VERY HIGH STRAIN RATES

In order to measure the material properties in the conditions of metal cutting, wire drawing and missile penetration, a biaxial shear experiment has been performed at very large strains C4) and at very high strain rate (0.4xl0 s) using a special specimen having a thin (0.25 mm) ring-shaped gauge part. The loading device is a tension-torsion Hopkinson bar apparatus which can be used also at low and medium strain rate. A special electroptical technique has been developed for the direct measurement on the specimen of the axial and angular displacements and of the shear stresses. Equivalent stress strain curves from shear tests of AISI 316 have been compared with tension curves.

Energy Transfer and Regional Blood Flow Changes following Missile Trauma

The hemodynamic response to missile injury was studied in the hind legs of dogs. Spherical projectiles were used and velocity and mass were varied. The regional arterial blood flow to the injured thigh was recorded and the energy transfer to the tissues determined. In addition the presence within the aortic arch was recorded immediately after the impact of the missile. Missile penetration caused a marked peak of flow followed by a less pronounced elevation of the flow level for at least 30 minutes. The magnitude of the peak was related to the amount of energy transferred to the tissues. The origin of the circulatory changes is discussed. Shock waves of considerable magnitude were recorded within the aortic arch in connection with the bullet penetration.

A review of procedures for the analysis and design of concrete structures to resist missile impact effects

Concrete containment walls and internal concrete barrier walls are often required to withstand the effects of missile impact. Potential missiles include external tornado generated missiles (steel rods, steel pipes, wooden poles, and automobiles), aircraft crash, and internal accident generated missiles (turbine blade, and steel pipe missiles resulting from pipe break). Impacting missiles can be classified as either ‘hard’ or ‘soft’ depending upon whether the missile deformability is small or large relative to the target deformability. This paper only deals with the effects of ‘hard’ missile impact. Missile velocities between 100 and 1500 ft/sec are emphasized. ‘Hard’ missile impact results in both local wall damage and in overall dynamic response of the target wall. Local damage consists of spalling of concrete from the front (impacted) face and scabbing of concrete from the rear face of the target together with missile penetration into the target. If damage is sufficient the missile may perforate or pass through the target. This paper reviews the various empirical procedures commonly used for determining penetration depth, perforation thickness, and scabbing thickness for concrete targets subjected to ‘hard’ missile impact. Results obtained from these procedures are compared with test data results for low velocity impacts (200–1500 ft/sec). Design recommendations to prevent detrimental local wall damage are presented. Overall dynamic response of the target wall consists of flexural deformations and a potential flexural or shear failure if the strain energy capacity of the wall does not exceed the kinetic energy input to the wall by the striking ‘hard’ missile. Simplified procedures are defined for determining the dynamic response of the target wall and for preventing overall failure of the wall. Included are procedures for defining the effective target mass to be used in determining the fraction of the total missile kinetic energy which is transferred or ‘input’ into the target wall. Also included are procedures for defining the total strain energy capacity of the target wall as determined from the moment and rotational capacities of flexural yield hinges and the yield line deformation pattern of the wall. Lastly, criteria for preventing a premature shear failure are presented.