Principles of rational aviation structural design with the use of composite materials
Аuthors1*, 2**, 1***
1. Moscow Aviation Institute (National Research University), 4, Volokolamskoe shosse, Moscow, А-80, GSP-3, 125993, Russia
2. Experimental Design Bureau "Sukhoi", 23B, Polikarpov str., p/b 604, Moscow, 125284, Russia
**e-mail: vakravtsov@yandex. ru
The article deals with the principles of rational structural design with the use of composite materials (CM) based on taking into account peculiarities of abutting joints design. There has been analyzed distribution of local stress in the area of bolt joints installation at stretching and compressing (crushing) of CM. It is shown that magnitude of crushing compressive stresses which cause splitting (gauging) of CM threads in the areas where CM mate the adjacent structure is significantly larger than that of stresses in the regular CM area. Such stresses appear in the areas of fittings installation at loading the structure made of CM and typically mean the beginning of structural damage. There has been formulated a principle of weight efficiency being primarily affected by the use of CM in structures of abutting joints mass.
There has been substantiated the choice of technology of CM structures production which meets the requirements of structural and force diagram of an aircraft unit. The article contains examples of applying the traditional autoclave technology of CM structures production and the perspective PTM technology of designing the typical construction of high-lift devices unit of an aircraft. It is shown how application of technology which does not correspond to the given structural and force diagram (SFD) of a unit affects structural rigidity and strength. There has been formulated a principle of mandatory correspondence of the SFD of a given unit and the capabilities of the CM structure production method being used.
There has been shown complexity of matching tolerances of butted metal parts and CM parts. For example, coupling sizes and surfaces of load-carrying supports used for attaching a CM part to the adjacent structure usually have tolerances which correspond to mechanically processed surfaces, while surfaces of CM parts correspond to free dimensions which are the result of polymerization. There has been formulated a principle of mandatory compliance of tolerances for coupling sizes of parts being butted based on constructional capabilities of a metal structure and technological peculiarities of CM production.
Keywords:composite material, rational design, technology, unit
- Vassilyev V.V., Dobryakov А.А., Molodtsov G.А., Tsarakhov Y.S. Osnovy proektirovaniya i izgotovleniya konstruktsii letatel’nykh apparatov iz kompozitsionnykh materialov (Fundamentals of design and production of aircraft structures made of composite materials), Moscow, MAI, 1985, 218 p.
- Endogur A.I. Konstruktsiya samoletov. Konstruirovanie agregatov planera (Aircraft structure. Airframe units design), Мoscow, MAI-PRINT, 2012, 496 pp.