Amin Poursafar - Department of Mechanical Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran.
Saeid Saberi - Department of Mechanical Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran.
Rasoul Tarkesh Esfahani - Department of Mechanical Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran.
Meisam Vahabi - Department of Mechanical Engineering, Najafabad Branch, Islamic Azad University, Najababad, Iran.
Javad Jafari Fesharaki - Department of Mechanical Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran.

The roll forming process plays a critical role in producing various sections used in industries. Also, the quality of these products is strongly affected by the thickness of the strip, the distance between stands, the section web, the flower pattern, and the plastic anisotropy. Therefore, the influences of practical factors on the bowing defect of the symmetrical U-section are experimentally and mathematically characterized in the present research. The investigated material is DC۰۳ (۱.۰۳۴۷) steel. Different prediction models such as linear and non-linear model based on the general full-factorial design of experiment are used to predict the effect of following factors on the bowing defect. Accuracy of the analytical model was verified by comparing the output results with the practical data. Results show that the strip thickness of investigated material, the flower pattern, and the section web have the most significant effect on the bowing defect. Also, the anisotropic properties of the investigated material and the inter distance have the minor impact on the bowing defect, but the effect of material with considering the anisotropic properties on increasing the accuracy of process simulation results is very impressive and increases the accuracy of simulation results from ۸۴% to ۹۱%. Finally, the predicted bowing defect using the modified two-factor model was in ۹۱% agreement with the experimental results.

bowing defect, Design of Experiments, Full factorial, roll forming, symmetrical, U- Section