Curvature Distribution of Metal Strip in Processing Lines and the Resulting Tension- and Power Requirements
Sprache des Titels:
Internationales Forum Mechatronik, Tagungsband, Linz 2009
Within the production chain of metal strip and in particular at processing lines, a metal strip is typically bent multiple times under tension around rolls with different diameters. Depending on the material, geometry and loads, a transition from purely elastic to elasto-plastic deformation may take place at a “critical strip bending radius”. At specific rolls within a strip processing line, the actual bending radius is well below this limit value, yielding the necessity to take into account the effects of plastic dissipation, leading to tension and power losses.
The magnitude of such losses depends in particular on the value of the peak strip curvature (i.e. the reciprocal value of the actual bending radius at the contact area between strip and rolls). Observations at existing strip processing lines as well as elaborate simulation analyses point out that for some strips the bending radius in the contact region with a particular roll is significantly larger than the radius of the roll. This typically occurs at rolls with small diameters, especially for thick and hard strip, when the strip tension is low and the strip deflection is small. In such cases, the strip and the roll touch along a single line and not across a contact surface. Comparative calculations point out that the assumption that the strip always adapts to the curvatures of the rolls in a strip processing line leads in some cases to an unacceptable over-estimation of the power- and tension requirements.
In order to accelerate and facilitate the determination of the peak contact curvature of the strip, a flexible, simplified model was developed by employing Abaqus/Explicit. An extensive parameter study was performed, taking into account the following key parameters: material properties, strip thickness, strip tension and the “theoretical” deflection angle. The gathered results were embedded into an interpolation tool, which allow the instantaneous determination of the tension and power losses.