Editing Kinetic energy penetrator (section)

==Design==
The principle of the kinetic energy penetrator is that it uses its kinetic energy, which is a function of its [[mass]] and velocity, to force its way through armor. If the armor is defeated, the heat and [[spall#Antitank warfare|spalling]] (particle spray) generated by the penetrator going through the armor, and the pressure wave that develops, ideally destroys the target.<ref>{{cite web |url=http://xbradtc.wordpress.com/2008/07/07/heat-rounds-and-sabots |title=Heat Rounds and Sabots |url-status=dead |website=xbradtc.wordpress.com |archive-url=https://web.archive.org/web/20110718112901/http://xbradtc.wordpress.com/2008/07/07/heat-rounds-and-sabots/ |archive-date=2011-07-18}}</ref>

The modern kinetic energy weapon maximizes the [[Stress (mechanics)|stress]] (kinetic energy divided by impact area) delivered to the target by:
* maximizing the mass – that is, using the [[density|densest]] metals practical, which is one of the reasons [[depleted uranium]] or [[tungsten carbide]] is often used – and [[muzzle velocity]] of the projectile, as kinetic energy scales with the mass ''m'' and the square of the velocity ''v'' of the projectile <math>(mv^2/2).</math>
* minimizing the width, since if the projectile does not tumble, it will hit the target face first. As most modern projectiles have circular cross-sectional areas, their impact area will scale with the square of the radius ''r'' (the impact area being <math>\pi r^2</math>). For the same reason, "self-sharpening" through the generation of [[adiabatic shear band]]s is also a desired feature for the projectile material.<ref>{{Cite journal |last=Magness |first=Lee S. |date=1994-03-01 |title=High strain rate deformation behaviors of kinetic energy penetrator materials during ballistic impact |url=https://linkinghub.elsevier.com/retrieve/pii/0167663694900558 |journal=Mechanics of Materials |language=en |volume=17 |issue=2-3 |pages=147–154 |doi=10.1016/0167-6636(94)90055-8}}</ref>

The penetrator length plays a large role in determining the ultimate depth of penetration. Generally, a penetrator is incapable of penetrating deeper than its own length, as the sheer stress of impact and perforation ablates it.<ref>{{Citation|title=M829A3 penetration test|url=https://www.youtube.com/watch?v=EodS_Ss8a5I |archive-url=https://ghostarchive.org/varchive/youtube/20211211/EodS_Ss8a5I |archive-date=2021-12-11 |url-status=live|language=en|access-date=2020-02-22}}{{cbignore}}</ref> This has led to the current designs which resemble a long metal [[arrow]].

For monobloc penetrators made of a single material, a perforation formula devised by Wili Odermatt and W. Lanz can calculate the penetration depth of an APFSDS round.<ref>{{Cite web|title=Long Rod Penetrators. Perforation Equation |url=http://www.longrods.ch/perfeq.php|website=www.longrods.ch|access-date=2020-02-22}}</ref>

In 1982, an analytical investigation drawing from concepts of gas dynamics and experiments on target penetration<ref>{{cite journal |last1=Bondarchuk |first1=V.S. |last2=Vedernikov |first2=Y. |last3=Dulov |first3=V.G. |last4=Minin |author4-link=Vladilen F. Minin |first4=V.F. |title=Optimization of star-shaped penetrators |journal=LZV. Sib. Otd. Akad. Nauk SSSR Ser. Tekh. Nauk |language=ru |volume=13 |pages=60–64 |date=1982}}</ref>{{coi-source|sure=yes|date=July 2020}} led to the conclusion on the efficiency of impactors that [[Impact depth|penetration]] is deeper<ref>{{cite journal |last1=Bivin |first1=Y.K. |last2=Simonov |first2=I.V. |title=Mechanics of Dynamic Penetration into Soil Medium |journal=Mechanics of Solids |publisher=Allerton Press |volume=45 |pages=892–920 |date=2010 |issue=6 |issn=0025-6544 |doi=10.3103/S0025654410060130 |bibcode=2010MeSol..45..892B |s2cid=120416067}}</ref> using unconventional three-dimensional shapes.<ref>{{cite journal |last1=Ben-Dor |first1=G. |last2=Dubinsky |first2=A. |last3=Elperin |first3=T. |title=Area rules for penetrating bodies |journal=Applied Fracture Mechanics |publisher=Elsevier Ltd. |volume=26 |pages=193–198 |date=1997 |issue=3 |issn=0167-8442 |doi=10.1016/S0167-8442(96)00049-3}}</ref>