Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!att!cbnews!cbnews!military From: john%ghostwheel.unm.edu@ariel.unm.edu (John Prentice) Newsgroups: sci.military Subject: Re: non-penetrating hits on tanks Message-ID: <1991Feb18.051731.8866@cbnews.att.com> Date: 18 Feb 91 05:17:31 GMT References: <1991Feb15.073418.12551@cbnews.att.com> Sender: military@cbnews.att.com (William B. Thacker) Organization: University of New Mexico, Albuquerque, NM Lines: 37 Approved: military@att.att.com From: john%ghostwheel.unm.edu@ariel.unm.edu (John Prentice) In article <1991Feb15.073418.12551@cbnews.att.com> Graper Brad P (MTSD/FIO) writes: >Nonpenetrating hits can affect the target in several ways... >in some cases, with a kinetic energy penetrator you just bounce off and >little or no significant damage is done. In other cases the mass of the >penetrator is enough that if it hits at the right angle there is a >certain amount of ballistic shock imparted to the target. Ballistic >shock can damage electro-optical systems. The same applies to HE >projectiles. A big enough HE round will impart some ballistic shock >to the target, even if it doesn't do anything else. It should perhaps be noted however that it is relatively easy to protect against oblique impacts or HE. For example, spaced armor plates will stop most HE shocks completely, there is not good coupling between the first plate, the air space, and the next plate. Reactive armor would also be pretty effective. Spaced plates are also pretty effective at stopping oblique impacts of KE penetrators since the first plate tends to cause the penetrator to yaw as it penetrates so that it both hits even more obliquely (minimizing the penetration depth) or fragments (also minimizing the penetration depth). Of course, it all depends on the armor thickness and composition and on the nature of the impact. The other point to be made is that non-penetrating impacts can be quite lethal. You can hit straight on and manifestly fail to penetrate good modern armor. However, the shock imparted to the material may well spall the back surface and the fragmentation of that surface can be very lethal. Off the top of my head, I would guess that you only have to achieve penetration of about 1/3 the thickness of unibody armor to spall the back surface sufficiently to kill the crew. John -- John K. Prentice john@unmfys.unm.edu (Internet) Dept. of Physics and Astronomy, University of New Mexico, Albuquerque, NM, USA Computational Physics Group, Amparo Corporation, Albuquerque, NM, USA