however, different requirements may be placed on them. In the “rod and cone" docking device there are usually no roll shock absorbers. This is due to the fact, first, that the moments of inertia of the spacecraft relative to the longitudinal axis X, as a rule, are significantly less than those relative to the transverse axes y and z (see Table 5.1). Second, in impacts before linkage there are virtually no roll perturbations; consequently, the energy of roll rotation is considered to be an initial condition, that is, the relative velocity on first contact . For example, in the docking of two Soyuz spacecraft, the maximum initial velocity and ; thus the maximum energy This energy is easily absorbed by twisting of the rod. It should be noted that in this docking device, after linkage there may arise an additional perturbation due to the interaction of the latches with the tapers of the grooves for roll equalization in the recoil of the longitudinal shock absorber; however, the velocities produced are relatively small. In rating the shock absorbers of the “rod and cone” docking device, as a rule, one can be limited to two-dimensional models of interaction, due to the relatively simple geometry of the docking mechanism. 5.5.1. Basic Concepts Impact with the cone is decisive in designing shock absorbers for “rod and cone” docking devices. The correlations between the equivalent masses (Figure 5.10) for central and lateral , impacts are such that for the majority of designs, and are substantially smaller than mx (see Table 5.1). This is due to the fact that the ratio of radii of inertia to the radii vector of the point of interaction is relatively small, that is, in formulas (5.5 and (5.7) are substantially smaller than unity. As a result, the energy in the central impact is significantly larger than in impacts with the cone. This correlation makes it reasonable to have staged characteristics of the longitudinal shock absorber. This has a number of advantages: lateral forces on the rod are decreased (acceptable lateral loads on the rod are also significantly smaller than axial ones); it is easier to obtain low values of
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