Prediction of springback occurence after tube bending operation

Tube bending operations are mainly used in the industries such as automotive, aerospace and shipbuilding; they are also utilized in the production of piping equipment, hydraulic systems and some parts of the heat exchangers. Tube bending operations can be carried out in a traditional manner that needs the help of an operator; they are also performed by using CNC tube bending machines. Some of the bent tubes; which are the products of the tube bending machines, include some defects such as thinning, flattening, wrinkling and springback. Springback is defined as the deviation from the predefined bend angle after the end of the bending operation, and is affected by certain operational parameters related to the mechanical and geometrical properties of the tubes. The amount of the deviation from the predefined angle is also called as springback angle. Prediction of the springback angle reduces the production cost by reducing the amount of scrap as well as that eliminates the difficulties may occur in assembling the semi-manufactured tubes. In this study, finite element analyses (FEA) of tube bending operations are performed with the help of an explicit finite element code LS-DYNA® and the results are compared to the experimental results from the literature. Later on, various models are generated and finite element analyses are performed to obtain springback results for different values of effective geometrical and operational parameters. Various surrogate models are generated by treating these springback results as training points. A mathematical relation between the mentioned parameters and the springback angle is developed by using Polynomial Response Surface (PRS) model; which is one of the surrogate models used in this study that gives the closest results to the simulations.