Perforation Of Steel Plates Research Articles

Correction to: Perforation of Steel Plates with 7.62 mm APM2 Bullets

Correction to: Perforation of Steel Plates with 7.62 mm APM2 Bullets

Impact perforation of steel plates

The perforation of mild steel, stainless steel and high-strength steel plates subjected to impacts characterised as low-velocity (up to about 20 m/s) and moderate-velocity (20–300 m/s, approximately) are examined in this paper, wherein recent experimental data and some empirical equations have been compared. The threshold velocity for the normal perforation of metal plates focuses on cylindrical projectiles with various shaped impact faces, principally flat. A new criterion is suggested to distinquish between low-velocity and moderate-velocity impacts. Empirical equations are valuable for preliminary design purposes, and are sometimes adequate for final designs. Several empirical equations, which have been developed recently, are examined for their accuracy in estimating the perforation energy of plates in the two impact velocity regimes which have been examined in this article. It is noted that there is a paucity of experimental data when recognising the plethora of parameters which control the perforation of plates. This hinders the development of empirical equations, though surprisingly accurate predictions for perforation velocities are possible to achieve, even for practical problems. Nevertheless, numerical studies are therefore required to remove many of the restrictions on the validity of empirical equations, but these methods require a considerable amount of accurate experimental data on the dynamic material properties and failure criteria.

Fragmentation of armor piercing steel projectiles upon oblique perforation of steel plates

In this study, a constitutive strength and failure model for a steel core of a14.5 mm API projectile was developed. Dynamic response of a projectile steel core was described by the Johnson-Cook constitutive model combined with principal tensile stress spall model. In order to obtain the parameters required for numerical description of projectile core material behavior, a series of planar impact experiments was done. The parameters of the Johnson-Cook constitutive model were extracted by matching simulated and experimental velocity profiles of planar impact. A series of oblique ballistic experiments with x-ray monitoring was carried out to study the effect of obliquity angle and armor steel plate thickness on shattering behavior of the 14.5 mm API projectile. According to analysis of x-ray images the fragmentation level increases with both steel plate thickness and angle of inclination. The numerical modeling of the ballistic experiments was done using commercial finite element code, LS-DYNA. Dynamic response of high hardness (HH) armor steel was described using a modified Johnson-Cook strength and failure model. A series of simulations with various values of maximal principal tensile stress was run in order to capture the overall fracture behavior of the projectile’s core. Reasonable agreement between simulated and x-ray failure pattern of projectile core has been observed.

On deformation and perforation of ship structures under ballistic impacts

This paper investigates the characteristics of the deformation and perforation on thin-walled structures under ballistic impacts based on the DYNA3D numerical simulations. Perforation mechanisms of plates and numerical modelling techniques to simulate the response of thin-walled structures under ballistic impacts are discussed to some extent. A benchmark study on deformation and perforation of steel plates struck by a rigid projectile is made by a comparison with DYNA3D simulations and existing experimental results where available. Perforation behaviour of a naval shipside structure impacted by a cannon ball is simulated by DYNA3D. By the regression analysis of the present DYNA3D computations and some existing test data, a new empirical formula that relates impact energy absorbed up to perforation of the target plate with the impact velocity of the projectile is developed. The developed formula can cover a wider range of the impact velocity up to 800 m/s, while existing formulae are valid up to 120 m/s. It is concluded that the technology developed from the present study will be useful for design and hazard assessment of thin-walled structures to avoid the perforation by ballistic impacts.

Statistical Characterization of Corroded Steel Plate Surfaces

Perforation of steel plate is of considerable interest for the longer-term safety and integrity of ships hulls and tanks and for nuclear containment systems. This paper reports on the preliminary random field characterization of the surface of two sample corroded steel plates as a trial towards generating numerically the surface topology of larger areas of steel plate. Of particular interest is the maximum depth of penetration and its dependence structure across the plate area. The potential applications and the background to the modelling of corrosion loss and pitting are reviewed briefly to set the scene for appropriate surface characterization. Contrary to the assumptions often made for the statistical characterization of maximum pit penetrations, they are highly dependent. This makes representation using extreme value probability distributions questionable. An alternative probability-based form of representation is proposed.

The effect of target strength on the perforation of steel plates using three different projectile nose shapes

The effect of target strength on the perforation of steel plates is studied. Three structural steels are considered: Weldox 460 E, Weldox 700 E and Weldox 900 E. The effects of strain hardening, strain rate hardening, temperature softening and stress triaxiality on material strength and ductility are determined for these steel alloys by conducting three types of tensile tests: quasi-static tests with smooth and notched specimens, quasi-static tests at elevated temperatures and dynamic tests over a wide range of strain rates. The test data are used to determine material constants for the three different steels in a slightly modified version of the Johnson–Cook constitutive equation and fracture criterion.Using these three steel alloys, perforation tests are carried out on 12mm-thick plates with blunt-, conical- and ogival-nosed projectiles. A compressed gas gun was used to launch projectiles within the velocity range from 150 to 350m/s. The initial and residual velocities of the projectile were measured, while the perforation process was captured using a digital high-speed camera system. Based on the test data the ballistic limit velocity was obtained for the three steels for the different nose shapes. The experimental results indicate that for perforation with blunt projectiles the ballistic limit velocity decreases for increasing strength, while the opposite trend is found in tests with conical and ogival projectiles. The tests on Weldox 700 E and Weldox 900 E targets with conical-nosed projectiles resulted in shattering of the projectile nose tip during penetration.Finally, numerical simulations of some of the experimental tests are carried out using the non-linear finite element code LS-DYNA. It is found that the numerical code is able to describe the physical mechanisms in the perforation events with good accuracy. However, the experimental trend of a decrease in ballistic limit with an increase in target strength for blunt projectiles is not obtained with the numerical models used in this study.

Advances in Dynamics and Impact Mechanics

On the dynamic collapse of circular and square tubes under axial impact On analysis of axisymmetric crushing of tubes and frusta Crushing strength of ship structures On the side impact of hollow composite rail body shells Multibody systems dynamics methodologies for crashworthiness On the numerical simulation of the progressive collapse of polymer composite sandwich beams under impact loading Simplified analysis of square plates under explosion loading Ballistic penetration and perforation of steel plates - an experimental and numerical investigation Dynamic behavior of large-scale structures due to a low speed impact Dynamic response and failure of free-free beams under impact or impulsive loading Failure behaviour of prestressed concrete beams under high-speed and impact loadings.

Velocities of Steel Fragments after Perforation of Steel Plate

Mild steel fragments (rightsquare prisms, 1.593 cm. × 1.593 cm. × 0.711 cm.) were projected normally with velocity 1,469 m/sec. against mild steel plates of thickness between 0.21 cm. and 0.85 cm.; usually impact was with the full square fragment face. Perforation occurred by removal of a plug rather larger than the fragment face, but tending to diminish with plate thickness. Fragment and plug were shattered by the impact, the pieces emerging along somewhat divergent paths. Velocities were measured with a Cooper chronograph, and in general were approximately the same for the principal pieces of fragment and plug. The residual velocity of the principal pieces may be predicted with reasonable accuracy for plate thicknesses up to about 0.5 cm. by assuming momentum to be conserved between the attacking fragment and a plug of equal area. For thicker plates this leads to too high values of the residual velocity, presumably because of the neglect of the motion communicated to the rest of the plate. Fragments of velocity 900 m/sec. suffered very little breakage against 0.21 cm. plates; residual velocities were not measured. The mechanism of penetration is discussed.