Some scaling laws governing gun erosion

• Published in: Wear 1976-01, Vol.39 (2), p.307-322
• Main Authors: Ebihara, W.T., Hochrein, A.A., Thiruvengadam, A.
• Format: Article
• Language: English
• ISSN: 0043-1648; 1873-2577
• DOI: 10.1016/0043-1648(76)90057-0

Gun barrel erosion is one of the major problems limiting the velocity, range and accuracy of the projectile. The various interacting mechanisms causing erosion are discussed. The importance of developing scaling laws governing gun tube erosion is emphasized. The approach adopted in this paper for the development of scaling laws is inspired by similar attempts in cavitation and liquid impact erosion. The concepts of threshold erosion, erosion intensity, erosion strength and erosion parameter are extended, modified and applied to gun tube erosion. As a result, the outlook for developing scaling laws governing gun barrel erosion seems very promising. The nondimensional number called the erosion parameter is given by the ratio between the output intensity of erosion representing the energy absorbed by the material and the input intensity of erosion contributed by the erosive forces. The output intensity of erosion is given by the product of the rate of depth of erosion and erosion resistance of the material, whereas the input intensity includes the Poisson's ratio of the projectile, the maximum acceleration, the maximum velocity and the bore diameter. With the aid of a few justifiable assumptions, it has been shown that the rate of depth of erosion is directly proportional to the square of the bore diameter. Available experimental data support these results for velocity scale and size scale. Further experiments are required to test these predictions fully. The erosion state is highly dependent on the number of rounds fired; it has four stages including incubation, acceleration, deceleration and steady state periods very similar to other erosion phenomena. Previously developed erosion theory correlates well with the available gun tube erosion rates as a function of the number of rounds fired; this lends further support to the erosion model proposed in this paper. However, the interacting influences of thermal and chemical mechanisms must be carefully considered in any further developments.