THE MODELING STRESS-DEFORMED STATE OF THE WORKING BODY OF A FLEXIBLE TUBULAR SCREW CONVEYOR

Abstract

The paper investigates the stress-strain state of the working body of a flexible tubular screw conveyor designed for transporting bulk, granular, and lumpy materials along complex spatial trajectories. The relevance of the study is determined by the need to improve the reliability, durability, and operational efficiency of flexible screw conveying systems, in which the working body is subjected during operation to a complex combination of axial, torsional, contact, and dynamic loads. Particular attention is paid to the analysis of a flexible rope screw conveyor with helical winding, which, during material transportation, operates under conditions of simultaneous tension, torsion, and interaction with the conveyed material.

Within the study, analytical dependencies are obtained for determining the axial and angular displacements of the flexible rod system under different conditions of fixing the right support. Two structural variants are considered: with the right support fixed against axial displacement and without such fixation. This made it possible to evaluate the influence of boundary conditions on the deformation behavior of the working body and on the variation of stresses along its length. To assess the strength of the flexible rope, the Huber–Mises energy criterion was applied, which made it possible to determine equivalent stresses under the combined action of tension and torsion.

The constructed graphical dependencies showed that equivalent stresses have a clearly expressed nonlinear pattern of variation depending on the wire winding angle, angular deformation, and rope diameter. It was established that an increase in angular deformation leads to an intensive increase in the level of equivalent stresses, especially within the ranges of winding angles where the influence of shear deformation components is most pronounced. A comparative analysis of single and double wire winding showed that double winding reduces equivalent stresses on average by 1.7–2.3 times due to the partial compensation of torsion-induced components. This confirms the feasibility of using double winding to increase the strength, fatigue resistance, and stability of the working body of a flexible screw conveyor.