A comment on “Predicting metallic armor performance when impacted by fragment-simulating projectiles–model review and assessment”, by W. Schonberg and S. Ryan, Int. J. Impact Eng. (2021)

• Published in: International journal of impact engineering Vol. 175; p. 104522
• Main Authors: Rosenberg, Z., Vayig, Y., Rubin, S.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.05.2023
• Subjects: Ballistic limit velocity; FSP; Metal targets; Metal targets; FSP; Ballistic limit velocity
• ISSN: 0734-743X; 1879-3509
• DOI: 10.1016/j.ijimpeng.2023.104522

•The ballistic limit velocities of FSPs perforating plates of metallic alloys are examined.•We show that the failure properties of the plate material play a major role in this FSP/plate intercalation.•We find that the ballistic limits of FSPs impacting various aluminum alloys are practically insensitive to the alloy's strength. In a recent article Schonberg and Ryan (2021) reviewed nine analytical models from various sources, and examined their ability to predict the experimental ballistic limit velocities (Vbl) of various metallic plates impacted by fragment simulating projectiles (FSP). These models analyzed the complex FSP/plate interaction, through simplified force equilibrium or energy conservation considerations. Schonberg and Ryan (2021) found that these models can predict the ballistic limit velocities to within ± 50% for more than 50% of the data base entries. On the other hand, they point out that "these models do not include the ductility and toughness properties of the materials involved", referring to the oversimplifications made in these models. The predicted V50 values were given in these models in terms of the plate's properties (strength, density and thickness), as well as the density and dimensions of the projectile. In particular, these models result in monotonic expressions between the predicted Vnl values and the corresponding strengths of the plates. The purpose of our comment is to demonstrate that, in fact, the test data in many cases do not follow this prediction.