PL213573B1 - Production method of I-bar section with gentle bending - Google Patents

Description

The subject of the invention is a method for producing an I-section with a gentle bend.

In the mid-twentieth century, the first structures were described and built using cold-formed thin-walled profiles, which were characterized by high stiffness and low weight. In the most commonly used, in practice, thin-walled beams - e.g. channels - with increased lengths, the influence of bending-torsional stiffness disappears, which reduces the critical loads. These problems were addressed in their studies by Romanów R., Strength of frames and vehicle bodies. Ed. Communication and Connectivity. Warsaw 1988, Weiss S., Giźejowski M., Stability of metal structures. Arkady, Warsaw 1991 and Życzkowski M., Mechanika Techniczna, Strength of structural elements. T IX, PWN, Warsaw 1988. There is a possibility of increasing the share of bending-torsional stiffness in the deformation of the beam, and thus increasing its resistance to loss of stability - torsion, by appropriate shaping of the cross-section, without the need to increase its cross-sectional area. Moreover, it is possible to control the position of the transverse force center also by means of an appropriate shape of the cross-section, which was published in the works of Magnucki Κ., Some problems of optimization of bar structures and shells with regard to elastic stability. Hearings No. 292, Wyd. Politechniki Poznań skiej, Poznań 1993, Magnucki K., Elastic buckling of selected flanges of cold-formed thin-walled beams. PhysicalMathematical Modeling and Informational Technologies, 3, 2006, 116-128, Magnucki K., Ostwald M .: Optimal design of selected open cross sections of cold-formed thin-walled beams. Publishing House of Poznan University of Technology, Poznan 2005, Magnucki K., Ostwald M., Optimal design of open cross sections of cold-formed thin-walled beams. Proc. Of the Fourth Int. Conference on Advances in Steel Structures. Shanghai, China, Z.Y. Shen et al. (Eds.) Elsevier, 2005, 1311-1316, Magnucki K., Lewiński J., Stasiewicz P., Optimal sizes of a ground-based horizontal cylindrical tank under strength and stability constraints. Elsevier: Int. Journal of Pressure Vessels and Piping, 81, 2004, 913-917, Magnucki K., Szyc W., Stasiewicz P., Stress state and elastic buckling of a thin-walled beam with monosymmetrical open cross-section. Elsevier: Thin-Walled Structures, 42, (1) 2004, 25-38, Magnucki K., Maćkiewicz M., Lewiński J., Optimal design of a mono-symmetrical open cross section of a cold-formed beam with cosinusoidally corrugated flanges . Elsevier: Thin-Walled Structures. 2006. The problems of strength and stability of these structures were discussed in monographic studies, e.g. Hancock GJ, Cold-formed steel structures, Journal of Constructional Steel Research, 2003, vol. 59, no 4, pp. 473-487, and Magnucki Κ., Ostwald M .: Optimal design of selected open cross sections of cold-formed thin-walled beams. Publishing House of Poznan University of Technology, Poznan 2005.

Among the work on thin-walled bars-beams, most of the focus is on strength and stability problems, and much less attention is paid to the optimal shaping, especially of open sections, of thin-walled beams, while limiting both the strength and stability conditions. In the 1980s, Życzkowski, Szymczak, Matulewicz were the first to deal with the formation of closed and open sections and the optimal selection of dimensions of compressed, twisted and bent beams. The limitations in the optimization of the discussed structures are the conditions of strength, stability and geometric. The structure's own weight has a decisive influence on the manufacturing cost, and in the case of vehicles, also on the operating cost.

The essence of the invention is a method of producing an I-section with a gentle bend by bending, which consists in the fact that a sheet of metal with a width equal to the sum of the width of the web and twice the width of both flanges, bends on two sides at an angle of 90 ° along two edges forming the outline of the web, then the sheet is gently bent 180 ° along the first edge line of each shelf with a bend radius r, and the sheet is bent 180 ° along the second edge line of each shelf towards the interior space of the section.

It is advantageous for the sheet to be bent along the edges in opposite directions.

It is also advantageous if the sheet is bent along the edges in coincident directions.

It is also particularly advantageous when filler is introduced into the spaces of the shelf.

It is particularly advantageous if polyurethane foam is used as filler.

Furthermore, it is preferable that foamed metal is used as filler.

Thanks to the application of the method according to the invention, the following technical and operational effects were obtained:

- the possibility of obtaining a high ratio of load capacity to weight,

PL 213 573 B1

- simple manufacturing technology,

- high dimensional accuracy,

- easy assembly,

- the ability to adjust the shape to the customer's wishes.

The subject of the invention has been shown in an exemplary embodiment, where Fig. 1 shows a cross section of an I-section with a gentle bend.

The method of producing an I-section with a gentle bend by bending consists in the fact that a sheet with a thickness t equal to 0.2 mm and a width equal to the sum of the width of the web 1 and the double width of both shelves 2, is bent on two sides at an angle of 90 ° along two edges 3 forming the outline of the web 1, then the sheet is gently bent at an angle of 180 ° along the first edge line 4 of each shelf 2 with a bend radius r = 5 mm, and then the sheet is bent at an angle of 180 ° along the second edge line 5 of each shelf 2, towards the inner space of the section. The sheet is bent along the edge 3 in opposite directions.

In another variant, the sheet is bent along the edge 3 in coincident directions.

A filler 6, e.g. polyurethane foam, is introduced into the resulting spaces of the shelf 2 in a known manner.

For the production of the section, a sheet with a thickness t in the range of 0.2-2 mm is used.

Claims (6)

1. The method of producing an I-section with a gentle bend by bending, characterized in that a sheet with a width equal to the sum of the width of the web (1) and twice the width of both flanges (2), is bent on two sides at an angle of 90 ° along two edges (3 ) forming the outline of the web (1), then the sheet is gently bent at an angle of 180 ° along the first edge line (4) of each shelf (2) with a bend radius r within 3-8 mm, and then the sheet is bent at an angle of 180 ° along the second an edge line (5) of each shelf (2) towards the inner space of the section. 2. The method according to p. A method according to claim 1, characterized in that the sheet is bent along the edge (3) in opposite directions. 3. The method according to p. A method as claimed in claim 1, characterized in that the sheet is bent along the edge (3) in coincident directions. 4. The method according to p. The method of claim 1, characterized in that a filler (6) is introduced into the spaces of the shelf (2). 5. The method according to p. A method as claimed in claim 4, characterized in that polyurethane foam is introduced as filler (6). 6. The method according to p. 4. The process as claimed in claim 4, characterized in that a foamed metal is introduced as filler (6).