Annotation: The pyrobolts, or explosive bolts, belong to the pyrotechnical devices with monolithic case consisting o f the cap, as a rule with hexagonal surface, and of cylindrical part with thread. The pyrobolts are separated into parts using the pyrotechnical charge placed inside the case. Owing to the simple design, reliability and short action time, the pyrobolts have found wide application in aerospace engineering for separation of assemblies and bays, in particular, stages, head modules, launching boosters, etc. So, for example, about 400 pyrobolts are used in the Proton launch vehicle. The designs of pyrobolts are markedly different. By method of explosive substance action on case structural elements, the pyrobolts are divided into two types: the pyrobolts using the shock wave formed at detonation of brisant explosive substance for case wall destruction and the pyrobolts using the pressure of gases arising at pyrotechnical charge blasting. By method of separation into parts, they are divided into fragmenting pyrobolts with ridge-cut, with piston, and shear pyrobolts. The paper deals with the design of various types of pyrobolts, their disadvantages are considered. The Yuzhnoye SDO-developed pyrobolt of shear type with segments is presented that uses radial shear forces of segments located in the hole of cylindrical part to separate the case parts. The above segments a re actuated using a rod with sealing rings and a piston connected to the rod through a rubber gasket; the piston moves under pressure of gases formed during pyro cartridge action. The following calculations are presen ted: strength analyses with determination of case load-carrying capacity; power analyses with justification of pyro cartridge selection for pyrobolt actuation. In the developed pyrobolt of shear type with segments, the case parts are separated without considerable shock loads and without high-temperature gases and fragments release into environment, ensuring reliable separation of bays and assemblies without damaging sensitive equipment.

Annotation: The paper considers the TZS-U design developed by Yuzhnoye SDO specialists for windward part of reusable spacecraft with external metal three-layer panel, U-like joint and tiled thermal protection, in which the problem is solved of compensation of thermal expansions and sealing of gaps; for optimization of structural mass. The specially created dispersion-hardened powder alloy based on nichrome and aluminum with yttrium dioxide with decreased specific mass of 7500 kg/m3 and lighter felt of MKRF brand are used , and honeycomb filler of three-layer panel is replaced by the filler with square cell.

Annotation: The technique is proposed to determine width of the spherical-type flange coupling’s metal gasket clamping area by the specified joint tightening force considering the joint geometry and mechanical properties of the gasket material.

Annotation: The main task of the radiotransparent radome design is to develop a structure that reliably protects the aircraft components, sensitive instrumentation of the guidance system from incoming air flow and heating in all phases of operation, meeting all the requirements of minimum weight, allowable temperature under the radome, strength, centre of mass and radio characteristics. Development of the radome solves the complex task of coupling and optimization of the geometric aspects of design with physical-mechanical, radio and thermal properties of materials. The article dwells on the aspects of development of the radiotransparent radomes depending on the aircraft flight speed; basic requirements for the selection of outside perimeter configuration; structural materials, providing the required radio properties in combination with minimum mass and necessary strength, acceptable temperature inside the fairing. Yuzhnoye-developed radome for the up to 5 M aircraft was considered, consisting of ogive shell made of АФ-10ПО fiberglass, heat-resistant tip and structural ring made of aluminum alloy. Methods of thermal and strength analyses of the shell are considered, results of calculations confirming the fitness for work of the structure are presented. Options of configuration with ceramic shells and methods of their coupling with rings are presented for the aircraft that reaches up to 5 M speed. Basic principles of radiotransparent radomes development and aspects of ceramic shells coupling with structural rings are considered, as well as the results of strength analyses and thermal calculations that ensure the performance of the structure and equipment in the area under the radome.

Annotation: Strength calculation example of the specific design bellows is taken to consider one of the possible approaches to the numerical simulation of the stress and strain state of the multilayer bellows. Proposed approach is based on the use of axial symmetry of the structure for transition from 3D calculation model to 2D one. Calculations take place in the elastoplastic setup, using the software package of the finite elements method. As an example of the proposed approach static and fatigue strength of the three-layer steel bellows of the Cyclone-4M fuel supply line are calculated. Calculation of the static strength of the bellows, loaded with internal pressure, showed that layer stresses achieve yield strength, at the same time preserving the bearing capacity of the structure. Results of the simulated change in the stress and strain state of the bellows per one cycle of the variable reloading were taken to find the amplitude of the plastic deformations in the most loaded area of the bellows, which allowed estimation of its fatigue strength in the conditions of lowcycle loading. Advantage of the proposed approach to the multilayer bellows strength evaluation is that it does not require large volumes of RAM and time to do the calculations.