Development and design choice of ceramic rocket fairing and metal bulkhead joint

Аuthors

Rogov D. A.^*, Latysh S. I., Vasyukov M. V.^**

Obninsk Research and Production Enterprise "Technologiya", 15, Kievskoe shosse, Obninsk, Kaluga region, 249031, Russia

*e-mail: rogov.dmitry.76@yandex.ru
**e-mail: fantol@yandex.ru

Abstract

The paper considers problems of selection of the joint of ceramic shell and metal bulkhead of nose antenna dome, that meets the condition of available analog design rethink minimum, while maintaining all the geometric dimensions of parts used. We show by calculations the process of design styles selection with further optimization of their geometrical parameters. Application of the other constructional materials used for a given assembly is inadmissible on radio engineering and mass considerations. The results of computational optimization have been proved by the field tests of prototype items.

Based on the results of the prototype air-to-air missile tests, the frame design has been corrected, and the maximum stresses in the ceramic shell of the fairing with the frame of corrected design have been determined. Application of modified frame together with the maintenance of air-tightness contributes to the product weight saving and stresses reduction in the ceramic shell, as well as improves the production effectiveness of the frame assembly.

At operation mode of 110 s duration maximum temperature of the inner attachment frame heating changes from 220 °C (at the shell edge) to 340 °C (in a thin part of the frame). The maximum tensile stress in the shell caused by the temperature is 15 MPa, and the maximum tensile stress caused by the force factors does not exceed 9.5 MPa. The total maximum tensile stress in the shell at the end of the operation mode is 17.3 MPa in the circumferential direction and it is 15.85 MPa in the meridian direction.

With all abovementioned taken into account, we recommend to accept the proposed design of the frame and to refine it with the aim to determine optimal geometrical parameters and develop the technological process which will make it possible to meet all the requirements of the frame design specification.

After analysis of frame design advantages and disadvantages, we plan to develop a new variant of the frame design with the following positive characteristics of previously analyzed structures, which will provide:

• air-tightness regardless of the frame assembly conditions;

• minimum stress in the ceramic shell;

• minimum frame weight;

• fewer parts to be assembled with the use of the sealant, simplified frame assembly.

Keywords:

aircraft, missile, ceramic, fairing shell, frame assembly, optimization, designing

References

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