Re-visiting the mass-flux model for Explosive Reactive Armor and the effect of plate thickness

Effect of material properties on interaction of ceramic and glass flyer plates with hypervelocity jet

“…It is seen that the gauge on the glass starts the acceleration with a 2–3 μs delay, which is a very critical shortcoming since this delay causes at least 14 mm more of jet precursor to escape without interaction depending on the jet tip velocity. This shortcoming is caused by the combined effect of slow sound speed and increased thickness in glass (or similar low density materials), 10 thus the stress waves causing the acceleration of the plate need more time to reach the other surface of the plate, and the reflections take more time. On the contrary, relatively higher sound speeds of ceramics account for the increased thickness, and the time loss from acceleration is minute.…”

“…Moreover, the interaction zone of the flyer plate with the jet is larger since the flyer plate is much thicker. This particularly results in improved interaction efficiency of the back plate, which disrupts the center and the slow parts of the jet 10 . A higher fracture toughness supports the acceleration of the front plate by keeping the integrity of the plate for longer at the initial acceleration phases and provides an indirect contribution to the performance.…”

“…Recent work of Mayseless 10 extended the mass‐flux model 2 . It is seen that increased thickness of the flyer plate yields higher efficiency of the ERA cassette, in particular for the back plate, which interacts with slower parts of the jet.…”

“…It is first proposed by Held, 1 and the theoretical model is established by Mayseless et al 2 Development in the Warsaw Pact countries is described by Rototaev 3 . In scientific literature, investigation on working principles of ERA is published in several studies 4–10 . Additional references dealing with the interaction of jets with flyer plates are given in references 11–15 …”

“…3 In scientific literature, investigation on working principles of ERA is published in several studies. [4][5][6][7][8][9][10] Additional references dealing with the interaction of jets with flyer plates are given in references. [11][12][13][14][15] The common ERA cassette construction consists of an explosive layer sandwiched between two steel plates.…”