ANALYSIS OF THE ACCURACY OF THE CONVERGENCE OF A NUMERICAL SOLUTION OF THE METHOD OF FINAL ELEMENTS AND THE CONTACT PROBLEM OF A SOLID DEFORMABLE BODY ON THE EXAMPLE OF THE WINGOF THE PLANE CONNECTED WITH THE FUSELAGE

The paper presents an analysis of the stress-strain state (SSS) of the nodes connecting the wing and fuselage of the aircraft as the most critical part in terms of strength and structural safety of the airframe design. The analysis was made by the example of the structure of the lug type joint, which is often used in aircraft construction. The study was conducted on the basis of the finite element method (FEM), with an analysis of the accuracy and convergence of its numerical solution. A special feature of the study is the use of the contact problem of the theory of elasticity in the FEM solution. The presented approach allows, in the analysis of highly loaded prefabricated structures, identifying the required level of discretization in the finite element (FE) model with the presence of areas with stress concentration in it. The study was conducted in comparison with the use of the well-known results of an experimental and theoretical approach presented by A. Voit, and traditionally used in the design and determination of the stress state of a lug joint. The specificity of the traditional approach is the averaging of the stresses of the lug deformable parts in areas with a maximum stress gradient. In this case, an analysis of the accuracy and convergence of the FEM with the solution of the contact problem makes it possible, with a high level of confidence, to determine and evaluate the complete picture of the stress distribution in the joint under consideration. The results of the analysis are aimed at improving the reliability and durability of the work of the lug type nodes, as well as at reducing the direct material and time costs during their designing.