Stresses and Deformations of Curved Tubes which have a "D" Type Cross Section
The purpose of this study was to analyze the experimental results related to variations in the stresses on the walls of thin wall curved tubes and the variation in the deformation of the tubes whose cross sections were "D" shaped. The specific example was a Bourdon tube. This study compared the mechanical characteristics of strength and deformation between curved tubes with "D" shaped cross sections and those with other types of cross sections (such as: thin wall flat-oval cross sections and elliptical cross sections). The stress distributions on the walls of the tubes had complex dynamic combinations, because the tubes were comparatively flat and had relatively thin walls. Therefore, these experiments were carried out by measuring stresses on the walls of these tubes using strain gauges pasted on the walls. The experimental result were as follows: The displacement of the tube ends and the maximum stresses of the thin wall Bourdon tubes with the "D" cross section, the flat-oval cross section and the approximately elliptical cross section (nearly pointed-arc cross section) were influenced by the height-to-width ratio of the tube cross section, the thickness of the wall, the radius of the tube, the tube angle, the material and the curvatures of arcs of both ends which are the major axis and the minor axis of the tube cross section.
Key words : Bourdon tube, wire strain gauge, stress distribution, deformation, cross-sectional form