A note on the cavitation phenomenon in metallic plates perforated by sharp-nosed rigid projectiles

We explore the perforation process of metallic plates impacted by rigid sharp-nosed projectiles at high velocities. In particular, we are looking at the diameters of the penetration hole in the plates through a series of 2D numerical simulations, in order to check for the occurrence of cavitation in finite-thickness plates. This phenomenon has not been observed by previous workers and we were looking for its effect on the perforation process. Our simulations show that for every projectile/plate pair there is a certain impact velocity which marks the onset of cavitation. These threshold velocities depend on the normalized thickness of the plates, as well as on their effective strength. Our simulations are supported by the results from perforation tests on plates made of a low strength lead-antimony alloy. The main conclusion from our work is that analytical models for plate perforation should take into account the cavitation phenomenon, especially for high velocity impacts.

Simulation of lead Antimony Alloy Solidification and its Experimental Validation

The solidification of metals continues to be a phenomenon of great interest to physicists, metallurgists, casting engineers, and software developers. It is a non-linear transient phenomenon, posing a challenge in terms of modeling and analysis. During the solidification of a casting in a mould, the heat-transfer between the casting and the mould plays a vital role. This paper attempts to study heat flow within the casting, as well as from the casting to the mould, and finally obtains the temperature history of some points inside the casting. The most important instant of time is when the hottest region inside the casting is solidifying. ProCAST software has been used to obtain the temperature distribution in the casting process by performing Transient Thermal Analysis. In this research work, solidification of lead-2wt%antimony alloy has been carried out in the different sizes of metallic mold to predict the formation of shrinkage during solidification. Theoretical results have been validated experimentally for a particular case of lead-2wt%antimony alloy solidification. Results obtained by simulation software are compared with the experimental reading of temperature and found to be in good agreement. Voids appeared at the top and isolated area of castings for the defect-free direct method used in this study.