Analysis of cold-formed residual stress considering coiling-flattening process
HU Sheng-de，CHENG Xue-peng，LI Li-xin，DING Fan，PAN Cheng-gang
（Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education，Wuhan University of Science and Technology，Wuhan 430081，Hubei，China）
Abstract：From two aspects that considering the strain hardening （bilinear kinematic hardening） and without considering the strain hardening（elastic-perfectly plastic body），to the current study analyzed the stress that were produced in coiling，uncoiling，flattening，bending and rebounding processes，and obtained the residual stress distribution along the thickness direction during the coiling-rebounding. The effect of considering the strain hardening and without considering the hardening on the residual stress distribution of cold bending is researched. The calculated results are compared with the measured residual stress. The results show that residual stress distributions that were predicted by the two prediction models is almost the same. As the yield occurred on coil，the longitudinal residual stress distribution was nonlinear along the thickness direction（when the yield did not occur on coil，the stress distribution was linear），and the horizontal residual stress distribution was linear. The residual stress was mainly tensile stress from outer surface to neutral layer（horizontal residual stress had a very small compression area at the outside of deformation zone），and it was the compressive stress from inner surface to neutral layer（horizontal residual stress had a very small tension area at the inside of deformation zone）. Both horizontal residual stress and longitudinal residual stress had the maximum value on the neutral layer. The calculated results agreed with the experimental results.
2017, Vol. 52 
