How to pierce tank armor. Lavrentiev’s theory of （如何穿透坦克装甲。）.pdfVIP

How to pierce tank armor. Lavrentiev’s theory of shaped explosive A. Eremenko November 30, 2011 Here is another nice example of application of conformal maps taken from [1, 2, 3]. The following phenomenon was discovered by the American physicist Charles Edward Munroe (1880). You put a cylindrical charge of high explosive (15 cm high, 4 cm diameter) on top of a thick armor plate (20 cm thickness) and explode it. You get a little dent (about 1 cm deep) in the plate. Now explode it at some height (6 cm) over the plate. There will be almost no trace on the plate surface. Now drill a conical cavity, opening downward, in the explosive charge from the bottom side of it. The effect increases: you obtain a little pit few centimeters deep. This is already a surprise: you used less explosive than in the first experiment and you achieve a stronger effect. Now cover the surface of the conical cavity by a thin (1.5 mm) layer of steel. You get a pit in the armor about 5 cm deep. And finally explode the charge with the conical cavity covered by steel at the height of 6 cm over the plate. This time you pierce the plate through! The physical explanation is that the conical cavity in the explosive forms a thin jet made of the steel covering the cavity, and this jet has so high kinetic energy, because of its velocity, that it pierces a thick armor plate. The effect is widely used since WWII in anti-tank weapons. The tanks are covered by armor plates, several centimeters thick. Normally, to pierce this armor by kinetic energy of a heavy shell you need very high velocity. This is achieved by a heavy cannon, a very bulky and expensive thing. (Most of the images found in Google under “anti-tank gun” show small caliber guns and even rifles which were obsolete by the early 1940-s