A numerical-experimental investigation on spring back in rectangular section thin wall hollows and extracting a relation to estimate twisted angle by considering strain harden behavior

Spring back is the geometric change made to a part at the end of the forming process when the part has been released from the forces of the forming tool. Upon completion of sheet metal forming, deep-drawn, twisting and stretch-drawn parts spring back and thereby affect the dimensional accuracy of a finished part. In wave guides bending and twisting elements are used to transmit waves. In the present work, the spring back of rectangular section thin wall hollows is investigated. In order to study the torsional behavior of the specimens, a finite element model is constructed by considering a material model with strain hardening behavior. After validating numerical simulation by experiment, twisted angle versus applied torque is presented according to FE model. In conclusion, a relation based on numerical and empirical results is proposed to estimate twisted angle before and after loading and unloading. In the other words, by using the present model, applied twisted angle to achieve the desired value could be obtainable.