A rectangular block is passed through set of rollers to obtain an I-shaped beam, as shown in the following figure:
Two types of rollers are used:
Top and bottom rollers
Horizontal cylindrical rollers pull the block from the top and bottom to increase the width and reduce the depth of the block. The rollers control the width of the flange parts of the I-shape. they are modeled using rigid target elements.
Side rollers
Vertical cylindrical rollers with small fillets at either end. The fillets are necessary to ensure smooth material flow. The side rollers pull the block from the sides to create the I-shaped cross section. They control the width of the web part of the I-shape. As with the top and bottom rollers, the side rollers are modeled using rigid target elements.
The following figure shows that the problem is symmetrical about two planes (XZ and YZ):
To reduce modeling and computational time, only one quarter of the model is analyzed.
The simulation is performed statically in two load steps with Nonlinear Adaptive Region scoped to the block body. In the first load step, the block is moved towards the rigid rollers to build up the rolling process. In the second load step, the block is moved further to simulate hot-rolling performed by the rollers.
As the block passes through rollers, large deformation occurs due to the high level of friction between the rollers and the block. Eventually, the full block passes through the rollers to achieve the I-shaped cross section. In such large-deformation problems, however, mesh distortion is common, which can lead to convergence difficulties and even analysis termination.