International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

This article examines the stiffness calculations for a wing pre-twisted relative to its spar. Such wings can be used in experimental aircraft to study changes in their aerodynamic properties during flight testing at various twist angles. Such variable-geometry wings require comprehensive investigation using strength of materials and elasticity theory. This problem is fundamental to the structural mechanics of aircraft.

The article deals with a problem of fatigue load calculations when designing the aircraft wing. Much of fatigue damage is done to the wing by occasional air gusts in turbulent atmosphere. Therefore, the author considers the pattern of continuous atmospheric turbulence that gives an idea of low-altitude gusts. It is at low altitudes that nonstandard flights are performed for which it is wrong to use the statistical data on fatigue damage available from the previously operated airplanes of the same class. The method is offered to determine the equivalent bending moments along the wing span in discrete flight modes and within the entire routine flight. The above method takes into account the profile parameters of routine flights, the dynamic vibrations of the wing and fatigue characteristics of the structural material. To prove the reliability of the method the calculation results have been compared to those of medium-range aircraft testing flights.

The paper presents a method for calculating the durability of structure regular zones in view of working stresses and aircraft routine flight profile. Application of the method is advisable at the early design stages. The method is based on the discrete atmospheric turbulence model and dependence model for durability calculation by nominal stresses. Fatigue damage for a routine flight has been determined as the amount of damage due to accidental loads and the damage resulting from enveloping ground-air-ground cycle, naturally repeated during each flight. It has been noted that the consideration of the fatigue curve break point in the low-stress area leads to an increase in the calculated durability by 10-15%. A comparison has been made of the calculated durability values for two airplanes with the experimental data of TsAGI. The correlation is satisfactory enough.

The aim of this work is to extract modal parameters of a light aircraft wing. Modal parameters like natural frequencies, and mode shapes characterise the dynamic response of a structure and can be used for determining of the wing divergence and flutter. The CAD (Computer-Aided Design) model plays a pivot role in the design and development phases of an aircraft. Creating drawings, preparing reports of assembly and part drawings, preparing bill of materials, the aircraft design becomes easier and faster with the use of CAD system.
CAD model has to be imported in FEM (Finite Element Method) software, and so it can do FE model, which have to be solved. In this work a light aircraft wing is modelled by SolidWorks software. After that the CAD model is imported in ANSYS Workbench. The FE model is generated and solved by using ANSYS Workbench. The first six natural frequencies and mode shapes are shown for the proposed light aircraft wing.