Analysis of the "ear-plugˮ type structure operation by the finite elements method and by the contact problem of elasticity theory solution

Аuthors

Turanov R. A.^*, Pykhalov A. A.^**

Irkutsk National Research Technical University, 83, Lermontov str., Irkutsk, 664074, Russia

*e-mail: romancheg08@mail.ru
**e-mail: pikhalov_aa@irgups.ru

Abstract

The wing to fuselage connection is one of the most critical part of any aircraft. Here, in most cases, the wing represents the main bearing surface, and the fuselage is the load. With the wing design complication, such as a caisson type, the urgent task of analyzing its fastening elements with the fuselage arises to obtain the most advantageous design in terms of mass and reliability. This problem has been traditionally solved by of empirical methods. This solution can be significantly expanded employing highly efficient theoretical methods that allow analyzing both the parts stress-strain state (SSS), and their conjugation conditions.

The results of experimental studies presented in the works of E.V. Ryzhov [7], show that while the joint structure loading, out of the total amount of deformations 80% from them are those at the parts joints, and only 20% are deformations of the parts themselves. Thus, in contrast to its monolithic analogue the operability of the prefabricated structure is determined by both the strength of the parts and the conditions of their conjugation (layout) aimed at ensuring the minimum level of stress concentration in the joints assemblies of the aircraft structure.

With the empirical approach, when solving design problems of this type, there is a need to create a large number of field test samples. As a result, the total and time costs are rather large. With the advent of modern computational technologies based on FEM, new computational techniques have appeared that allow the most detailed study of the perception of mechanical loads in the aircraft’s structural elements. They include the structural elements connecting the aircraft’s wing to the fuselage, which main component is the ear-plug design. Under certain operation conditions of the product (aircraft) the stress field in the presented structures attains the unevenness of a high gradient.

Thus, the task is relevant, and its implementation is possible by the finite element method and employing the solution of the contact problem of a solid deformable body, by building a finite element model and introducing a contact joint between the node elements (fork, ear, bolt, nut).

The basis of the design is an empirical method for calculating the stress-strain state of a fixed plug-type “Ear-plug” type, which is employed as a test object in this work.

Keywords:

aircraft, ear-plug connection, finite elements, stress-strain state

References

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