4 kN-m at a pressure in the internal cavity of the transition tunnel and without pressure. The change in the longitudinal size in the plane of application of /Vf7 under pressure was approximately two times greater than at zero pressure. A complex loaded state arises when loads act on the hulls. A precise calculation of tensions and deformations may be done, for example, using the method of finite elements [8]. In planning, tensions in the elements are estimated using approximation methods. The hulls of the hermetic docking devices for long-term orbital stations, for example, Salyut-6, are designed for long-term action of constant and sign-variable loads with up to cycles. The hulls undergo static and dynamic testing in the assembled docking assembly to define durability resources. Fatigue and the rigidity of construction are also tested. Hermetic hulls are manufactured by mechanical processing and are one of the most labor intensive parts of the spacecraft. Even stamped processing of the hull is a technologically complex task and its construction requires great care. Hermetic hulls are manufactured of the alloy AMg-6, which has satisfactory durability and good construction and technological properties (density, homogeneity, stability, and processing and welding properties, etc.). Docking frames of the hermetic hulls of created structures have a half-open outward cross section attached by stringers (Figure 3.2). The hull and locks of the first modifications were designed for the action of short-term relatively small external loads (bending momentum in the joint of up to . To reinforce the mechanical processing a weld of stringers was used; the weld, however, led led to a high concentration of tensions, which had a substantial effect on fatigue resistance. When the loads increase and the number of load cycles increases, a fully mechanically processed structure becomes more reasonable. This type of structure is used in machine tools with programmed control and is, overall, more technologically efficient. The APDA hulls are manufactured in thia way. 3.3. The Locks of Docking Frames 3.3.1. The Selection of Basic Parameters To eliminate or minimize the possibility of spontaneous opening of the joint, the locks of the docking frame should create a force of preliminary tightening
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