Deformation length in flexible roll forming

Flexible roll forming (FRF) is a novel sheet metal process for innovative manufacturing of variable cross-section profiles which are especially needed in the automotive industry to construct lightweight structures. One of the important parameters of the flexible roll forming process is deformation length which plays a key role in the design of interstand distance. This paper presents a new understanding on the deformation length in the flexible roll forming process by performing experimental tests and numerical simulations. Results show that in flexible roll forming, unlike conventional roll forming, the deformation length varies considerably in such a way that the maximum and minimum values of the deformation length appear in the stretching and compression zones, respectively. Hence, it is recommended that the deformation length in the stretching zone is considered for designing the interdistance of stands. Results also allow concluding that the increase of the forming angle α , flange length F , and yield strength Y and the decrease of thickness t increase the deformation length in all the regions of a variable cross-section profile.