Influence of prebuckling deformations on the buckling of circular cylindrical shells under external pressure.
Upon examination of the existing experimental data in the literature, this equation is found to describe correctly the relation between the experimental maximum erosion rate and the incubation time which is denned as the intercept of the maximum slope of an erosion curve on the time axis. Pearson's experimental results show that, for a first approximation, the number of impacts for incubation is proportional to D~3, and the maximum erosion rate to D 4.8'9 This is in agreement with Eq. (6). Equation (6) also shows that the maximum erosion rate will be proportional to (v — v e)mi or vmz if the incubation time is proportional to (v — ve)pl or vpz, respectively, where the exponents mi, pi, ... have the relations nn = — pi + 1 for i = 1, 2. This appears to be a correct description of the experimental results presented in Figs. 2 and 3.10 Finally, the values of k for all of the experimental data examined can be obtained using Eq. (6). The results which are listed in the original report5 provide additional confidence on the simple analysis by showing a limited amount of scatter. In conclusion, the present analysis seems to describe satisfactorily the intermediate stage of an erosion process during which the erosion proceeds at the maximum rate. The analysis, however, appears not applicable to the early and the late stages in which the erosion is probably affected by the material inhomogeneity and the change of surface roughness. Thus, for these two stages, it-might also be necessary to take into account the microscopic properties of materials in addition to the macroscopic properties, on which this study is based.