A novel analytical model for straightening process of rectangle-section metal bars considering asymmetrical hardening features

Abstract

The applied straightening moment and the springback after unloading with respect to the straightening process of rectangle-section metal bars have a direct influence on the straightening accuracy and efficiency. In this article, an asymmetrical hardening material model is first proposed to describe the stress-strain curves considering the asymmetrical features of yield stress and plastic hardening stage in tension and compression, and it is also compared with the traditional linear hardening material model. To accurately evaluate the elasto-plastic bending deformation and the springback in the straightening process, an analytical model for the loading and unloading moments is then established. The strain and stress distributions in elastic and plastic regions during the straightening process are also discussed in this article. Finally, the straightening experiments of rectangle-section metal bars under different heat-treated conditions are conducted on the ROSE-JZ50 straightening machine with displacement sensors, force sensors and strain gauges to validate the proposed analytical straightening model.

A General Stroke-Based Model for the Straightening Process of D-Type Shaft

“…Substituting Equations (5), (6), (9), and (10) into Equation 7, the bending moment within the section can be obtained. Substituting Equations (15) and (16) and the yield strength σ t of the material into equation M t = σ t I/R and then substituting the obtained parameter and the bending moment within the section into Equation 8, the bending moment ratio M of the D-type shaft can be obtained.…”

“…Substituting Equations (5), (6), (9), and (10) into Equation 7, the bending moment within the section can be obtained. Substituting Equations (15) and (16) Figure 9 shows the cross-section types of two special D-type shafts.…”

“…[7][8][9]. Zhang et al [10] established a straightening stress model based on elastic-plastic deformation theory and material loading characteristics.…”

“…The elastic-plastic analysis and mathematical modeling were explored for different parts, and several straightening algorithms were developed based on the curvature and load control [7][8][9]. Zhang et al [10] established a straightening stress model based on elastic-plastic deformation theory and material loading characteristics.…”

A Novel Modeling Method in Metal Strip Leveling Based on a Roll-Strip Unit

“…Zhang et al firstly proposed an asymmetrical hardening material model to describe the stressstrain curves considering the asymmetrical features of yield stress and plastic-hardening stage in tension and compression. e strain and stress distributions in elastic and plastic regions during the straightening process were discussed in their article [4]. Jin et al researched the rotation blocking mechanism of the triple-roller equal curvature rotation blocking straightening system to solve the problem of bar rotation during the straightening process [5,6].…”