No abstract

In the article the authors present a method of restrained elastomer bending of aircraft sheet parts with curved sides. Manufacturing of a part is carried out in two transitions; as a result of the first transition a part with thinning in the radial part is obtained, the second transition is carried out on the mold block of reduced height, as a result of which the resulting wave of excess material deforms along the radius of the bending mandrel. In the finished part, we can observe an increase in the thickness of the workpiece in the zone of the bend radius. Numerical studies of the process were conducted using the ANSYS/LS-DYNA software complex. As part of the study, the process flow model was worked out, the distribution of thickness of the material of the part over the entire surface under consideration was obtained, and graphs were plotted showing the elastomer pressure distributions and the deformation of the material of the part at characteristic points.

In the article, the authors present a method of constrained bending of aircraft sheet parts with curved sides by an elastic medium. The process of conducting constrained bending is described. A schematic description of the process is presented. The manufacture of a part is carried out in two steps. As a result of the first step, a piece is obtained with thinning in the radius part, the second step is accomplished with a unit die of reduced height. The resulting wave of excess material is deformed along the radius of the bending mandrel. In the finished part, an increase in the thickness of the workpiece is observed in the zone of the bending radius. The wave of excess material is formed due to a special allowance, the size of which is the critical factor for achieving this increase in thickness. The analytical model for determining the allowance is based on generally accepted assumptions and principles for calculating process parameters. To determine the allowance, an approximation of the shape of the excess wave by a tangential function is proposed. This allows you to get an analytical dependence that relates the geometry of the part and the thickening of the wall to the size of the allowance. The size of the allowance is limited to a certain range, the lower boundary of which is determined by the onset of plastic deformations, the upper one - by the possibility of loss of stability, leading to irreparable spoilage. The results are illustrated by graphs of the dependence of the minimum and maximum allowance for the side height on the ratios of the workpiece wall thickness, the radius of the side bending and the radius of the side in plan. Characteristic curves and analytical dependencies are presented in a dimensionless form, where the geometric parameters are assigned to the radius of the bending tool, that is, to the radius of bending of the part side on the inner surface.