2. Mechanics model of leveling process
2.1. Relationship between roller gap and curvature
It is very difficult if not impossible to develop an analytical model
to capture themain bending characteristics of H-beams with enough
details for two reasons. The first is that the leveling process cannot be
idealized simply as periodic problem since the magnitude of the
alternating applied loads and the roller gaps decrease in the leveling
direction. The other reason is that the residual curvature and stresses
for a cross section in the previous step are used to be defined as the initial
conditions of the current step. It means the effects of rolls are
coupled: the curvature and stresses under each roller are affected by
the other roller gaps. The residual curvature and stresses fromone roller
aremodified by the other rollers. Subsequently, this cross section of the
H-beam is subjected to the whole loading process.