Calculation of the Tubular Elements Made of Pressed Profiles

Abstract

This paper is dedicated to ensuring the strength of cargo equipment elements of transport aircraft. The strength of rollers of roller conveyors, which are made of standard pressed aluminum tubular profiles or composite tubular elements, is considered. The main disadvantage of these semi-finished products is the deviation of the diameter of these standard aluminum profiles, which leads to the emergence of eccentricity Δ between the axes of the outer and inner surfaces. The influence of eccentricity on the change in the values of normal and tangential stresses is considered. This analysis was carried out for standard diameters of tubular profiles at values Δ equal to half of the standard limit deviation of the outer diameter D. Calculations of normal and tangential stresses and their comparison with nominal stresses that occur in the absence of misalignment have been carried out. Calculations were made of the value c of the removal of the center of rigidity from the center of the circle of the outer border of the cross-section at different cross-section sizes of standard profiles with values of Δ equal to half of the standard limit deviation of the outer diameter D inclusively. The calculations showed an increase in tangential stresses τ in some cases by 64% and even by 213%. The obtained results indicate that the presence of Δ≠0 will have a negative effect on the resource of these elements. In order to eliminate the negative consequences, it is necessary to increase the requirements for the shape deviation of the tubular profiles in the input control.

Keywords

• cargo equipment of transport aircraft
• roller conveyor
• tubular profile
• misalignment
• influence of eccentricity
• thin-walled rod
• center of cross-sectional rigidity
• normal and tangential stresses
• shape deviation
• resource