![Sample our Engineering & Technology journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5933/TOC-Subject-Sample-2021-Engineering-Tech.jpg"})
Abstract
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.
Acknowledgements
This study was undertaken at the Ship and Offshore Research Institute (The Lloyd's Register Educational Trust Research Centre of Excellence) of Pusan National University, Busan, Korea. This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (Grant no.: K20903002030-11E0100-04610). The Lloyd's Register Educational Trust funds education, training and research programmes in transportation, science, engineering, technology and the safety of life, worldwide for the benefit of all.
Notation
| d | = | diameter of projectile |
| ri | = | radial location of impact |
| G | = | impact mass |
| H | = | plate thickness |
| L | = | length of projectile |
| R | = | plate radius |
| S | = | span of plate |
| Vo | = | impact velocity |
| ξ | = | ri/R |
| ρ | = | density of plate material |
| σay, σpy | = | yield stresses across and parallel to the rolling direction, respectively |
| σy | = | average of ref = "TSOSA704163ILM0001.gif"/ > σay and ref = "TSOSA704163ILM0001.gif"/ > σpy |
| σau, σpu | = | engineering ultimate tensile stresses across and parallel to the rolling direction, respectively |
| σu | = | average of ref = "TSOSA704163ILM0001.gif"/ > σau and ref = "TSOSA704163ILM0001.gif"/ > σpu |
| ψ | = | d/H |
| λ | = | σu/σy |
| Ωp | = | ref = "TSOSA704163ILM0001.gif"/ > GV2o/2σyH3, dimensionless perforation energy |