Fastener and design method

Abstract

The invention provides a fastener and a design method, wherein the fastener comprises a bolt body and a boundary molded surface, the bolt body and the boundary molded surface are integrally processed, the bolt body penetrates through a through hole of a connected device, and the end face, connected with the bolt body, of the boundary molded surface is in contact with the surface of the connected device; the boundary molded surface is in an irregular three-dimensional shape, wherein the shape of the boundary molded surface is determined by thermal expansion coefficients of materials of a connected device and materials of a fastener in all directions and in the thickness direction, the diameter of a bolt body of the fastener and the thickness of a connected structure. Under the heating condition, the contour of the boundary molded surface of the fastener and the contour of the molded surface of a connected material coincide and do not separate or interfere with each other, so that the damage risk caused by mismatching of thermal expansion coefficients is reduced, and the risk of high-temperature looseness of the fastener is effectively reduced.

Description

technical field [0001] The invention belongs to the technical field of fastener design, and in particular relates to a fastener and a design method. Background technique [0002] Thermal structure is very beneficial for heat protection and weight reduction, so it has attracted extensive attention in the aerospace field at home and abroad. In order to improve the space utilization rate of the projectile, some equipment, such as terminal guidance radar, etc. are generally placed inside the thermal structure. Therefore, most thermal structure cabins are designed with a cover for easy placement of equipment, and then use high temperature resistant metal fasteners Assemble and connect the cabin body and the hatch of the composite material. Due to the difference between the thermal expansion coefficient of the fastener and the thermal expansion coefficient of the thermal structure, for example, the thermal expansion coefficient of the metal fastener is an order of magnitude large...

AI Technical Summary

Problems solved by technology

Due to the difference between the thermal expansion coefficient of the fastener and the thermal expansion coefficient of the thermal structure, for example, the thermal expansion coefficient of the metal fastener is an order of magnitude larger than that of the ceramic matrix composite material, and the composite material selected for the thermal structure may be in two directions in the plane The coefficients of thermal expansion are different, such as 2.5D, three-dimensional braided C / SiC composite materials, etc., so the connection part of the cover will loosen during the heating process, which will affect the safe flight of the missile

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