The properties of the stiffening ribs shaped in thin sheetes with aviation alloy 2024- T3 by icremental forming method

Abstract

The paper presents the results of experimental research on longitudinal ribbing in thin sheets, made as stiffening ribs. The issue concerns ribbing formed in 2024-T3 aluminum alloy plates, 0.4 mm thick. The embossing was made using a relatively new technology, the so-called incremental sheet forming, which is a point of deformation of the material through the tool in the form of a plunger, gradually penetrated into the material in accordance with a defined path that determines the shape of the final embossing. Forming was carried out using a three-axis numerical milling machine using a 6 mm diameter tool with a head radius of R3. Embossments 120 mm long and 20 mm wide were formed. As part of the research, different depths of embossing were considered, grading them every 1 mm in the range from 1 to 5 mm. The highest value of the depth with the given value was assumed, because above the 5.5 mm depth the shaped sheet was cracking, so the value of 5 mm was considered the maximum for which the analyzes were carried out.

For the described embossments static buckling tests were made, on the basis of which it was found that the embossing depth of 4 mm is a critical value, because the buckling force for extrusions in the range from 1 to 4 mm increases in direct proportion to the depth of the ribbing, while at a depth of 5 mm force this falls.

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