the experimental and numerical study of the effects of holding force, die radius, pin radius and pin distance on springback in a stretch bending test

The stretch bending test is one of the methods for forming metals, especially sheets. in this method, a piece of a metal sheet simultaneously undergoes compressive and tensile forces, thereby being converted into a curved piece with a great curvature. in the present research, springback was studied using a u-form die in a stretch bending test, and the experiments were performed on st12 steels through a laboratory set-up. moreover, various parameters were investigated, including die radius, pin diameters, blank holding force (bhf), and distance between pins. the stretching depth was 10 mm. not to mention, springback is affected by technical and geometric parameters. for example, the results of the present study revealed that increasing the pin spacing led to the reduction of springback and for more spacing, the springback tends to spring-go, additionally, it was observed that a rise in the die radius, pin diameters, and blank holder force resulted in the reduction of springback.