Curved closed profiles and calculation of their optimal parameters

Relevance. A new technical solution of bent-closed profiles relating to light steel thin-walled structures (LSTS), which have high technical and economic indicators and are widely used in industrial and civil construction, is presented. Aim of the research. The characteristics of thin-walled structures can be further enhanced by shaping the modification of profiles, combining in its composition the outlines of closed and open outlines. Methods. By means of developmental studies and optimization and design calculations for bent-closed profiles, their new technical solution was developed, the originality of which was confirmed by patent examination. Results. New curved closed profiles (CCP) consist of a tubular part of a single thickness and a double-thickness rib. For their manufacture without welded, bolted or riveted joints, the sheet blank is made along the entire length with serrated longitudinal edges, the teeth of which are arranged relative to each other in a staggered manner and mutually bent in grooves between themselves after the curved profile is closed along its edge. The bends of the gear fasteners increase the thickness of the collapse and provide an increase in the shear strength of the joints of thin-walled elements. With equal dimensions in height and width of the CCP, they are optimized by the criterion of uniform stability, which is the same from the plane and in the plane of the supporting structure. Additionally, a series of pentagonal, triangular and trapezoidal profiles are presen- ted, in which the lateral faces are inclined relative to the vertical at angles of 45 and 60 degrees.