Numerical Simulation And Study Of Edge-wave In Roll-forming Process For Thin-walled Channel Steel Parts

With roll-forming products developing into thin-walled, high strength and light weight, complicated-section style in recent years, edge-waves easily happen in the roll-forming process of thin-walled channel steel parts, which greatly influences the forming quality. Although roll-forming has made a great development, there is almost no well-developed theory. The design of roll process only relies on personal experience. Thus it is of great importance to study the roll-forming process of thin-walled channel steel parts and the forming defects.In this paper, FEM numerical simulations of roll-forming process for thin-walled channel steel parts was carried out on ABAQUS, which revealed the rules and characteristics of metal deformation during the forming process. Meanwhile, the forming mechanism of edge-waves was analyzed and an orthogonal simulation scheme was set up using the fluctuation of edge-wave Δy as evaluation parameters. The influences of material yield strength(σs), forming passes(n), flange height(h) and the thickness of material(t) on edge-wave fluctuation(Δy) were analyzed either. Results are as following:(1) Larger stress and strain mainly occurred in the bending corner and they increased with the bending angle(namely with the forming passes number). Strain distributed more uniformly than stress. The sheet was stretched in width direction, while compression deformation happened both in length and thickness directions during the roll-forming process of thin-walled channel steel parts. In addition, the transverse strain components were much greater than the longitudinal strain and thickness direction strain components.(2) Edge-wave generated due to the longitudinal stress and the unrecoverable plastic strains on each point of the flange, and they were different both along the part length and along the flange height. The bending moment occurred at the flange edges because of the different longitudinal stress. The flange edges tilted outward due to the longitudinal plastic elongation in the longitudinal tensile stress areas, while the flange edges tilted inward for the longitudinal plastic compression at the longitudinal compressive stress regions.(3) Material yield strength(σs), forming pass(n), channel steel flange height(h) and the thickness of material(t) all had effects on the generation of edge-wave and on the fluctuation of edge-wave(Δy). Influences of the mentioned 4 factors on Δy were also found to be h>t>σs>n.(4) Edge-wave fluctuation(Δy) decreased with the increase of s? and t, but increased with h, first decreased then increased with the increase of n.(5) To avoid edge-waves generation during roll-forming process of thin-walled channel steel parts, the flange height should be as small as possible and the material with high yield strength is supposed to be chosen. When designing the roll-forming process of thin-walled channel steel parts, it is advisable to choose proper forming stands along with good lubrication and additional appropriate shaping process to control edge-wave fluctuation.