Air drag coefficient of textile-covered elastic cylinders – preliminary aerodynamic studies

This paper presents preliminary experimental results on the influence on the aerodynamic drag of a cylinder from the cylinder type (i.e., rigid or soft) and its textile surface. Both a rigid cylinder and a soft-body cylinder, with a gelatin layer, each with five different textile surfaces were measured in the wind tunnel using force measurement technology. The drag coefficient was determined for several Reynolds numbers. The study shows that the elasticity of a cylinder has a significant influence on the drag force and the airflow type. However, the influence of the soft-body cylinder depends on the respective fabric. With the given measurements, no exact statements can yet be made to quantify the influence. This influence must be studied independently and in conjunction with the textile surface in order to gain understanding of the overall system of airflow, textile and elastic body.

Inverse Thermoelastic Analysis of a Cylindrical Tribo-Couple

Within the framework of the one-dimensional model for a tribo-couple consisting of two elastic cylinders accounting for the frictional heat generation on the interface due to the roughness of the contacting dissimilar materials, a problem on the identification of the unknown temperature on one of the limiting surfaces of either inner or outer cylindrical layers is formulated and reduced to an inverse thermoelasticity problem via the use of the circumferential strain given on the other surface. To solve the latter problem, a semi-analytical algorithm is suggested, and its stability with respect to the small errors in the input data is analyzed. The efficiency of the proposed solution algorithm is validated numerically by comparing its results with the solution of a corresponding direct problem. The temperature and thermal stresses in the tribo-couple are analyzed.

On the deformation of micromorphic elastic beams

This paper is concerned with the deformation of beams in the framework of the linear theory of micromorphic elastic solids. First, the plane strain of anisotropic and homogeneous elastic cylinders is investigated. Existence and uniqueness results are presented. Then, Saint-Venant’s problem for micromorphic beams is formulated. A method is established to reduce the extension, bending and torsion to the study of some plane problems. Finally, the deformation of beams loaded on the lateral surface is investigated. As a special case, the solution of the flexure problem is obtained. The method is used to study the deformation of a micromorphic rod subjected to a uniform pressure on the lateral surface.

CALCULATION OF STRESS-DEFORMED STATE OF ELASTIC CYLINDERS UNDER TEMPERATURE AND HUMIDITY IMPACT

The actual scientific and practical problem of plane deformation of an elastic cylinder under conditions of temperature and humidity is considered. Various pipes, shafts, plain bearings, bushings from natural and modified wood, etc. have a cylindrical shape. An exact analytical solution of this problem is given for an isotropic cylinder in the case of stationary temperature and humidity exposure. All formulas for stresses and strains and stresses contain mechanical and thermophysical constants, which corresponds to the physical meaning. It is proved that the use of classical methods for solving this problem through the potentials of stresses and displacements leads to an undesirable result in which stresses or deformations do not depend on the thermophysical constant C_2, which contradicts the physical meaning.