Numerical Simulation Research On The Bending Cross-section Distortion Of Cap-Type Profile

Aluminum alloy thin-walled Cap-Type profile can meet the lightweight based products, also can realize the characteristics of energy saving and environmental protection in industrial production, has been widely used in the areas of aerospace and automotive. NC rotary-draw bending is one of the main forming methods of thin-wall profile, but the coupling effect of the forming process and die, involving multiple factors, and the cross-section distortion is a key factor affecting the quality of forming,the forming precision of the process. So, in this paper, through experiment and theory analysis and numerical simulation method, the rotary draw bending forming process of section distortion behavior systematically, A brief introduction of this paper and its results are as follows:(1) With forming characteristics of bending process of aluminum alloy thin-walled cap-type profile, a 3D FEM model for rotary draw bending process of aluminum alloy thin-walled cap-type profile was established based on the solve some key technology problems, such as contact, friction, boundary conditions, loading, etc. and its reliability was validated by experiment.(2)Then, base on the reliability FE model which has been built, the distributions of stress and strain in rotary draw bending processing of 5052 aluminum alloy cap-type profile were obtained. The mechanism of cross section distortion generated was revealed, and index scaling the distortion has been proposed. The results show that:with the rotary draw bending, profile of the equivalent stress and equivalent strain increases gradually; the cross section distortion increase along the bending direction distribution. The tangential tensile stress and tangential stress cause the cross section deformation of profile, once deformation exceeds the allowable range, it will be development of section distortion.(3)The influence laws of elastic modulus, Poisson's ratio, relative bend radius,bent speed, and forming parameters on Cap-Type profile of cross section distortion are obtained. The results show that: the cross-section increases with the increase of elastic modulus, the hardening index, the friction coefficient among bend die, pressure die,clamp and profile, relative bend radius, boost speed; while decreases with the increase of the yield strength, strength coefficient, the clearances among bend die, pressure die,clamp and profile, bending angle. The increasing bending speed is beneficial to reducecross-section distortion; But the influence of Poisson's ratio, the friction and clearance between wipe die and profile have little effect on the cross-section.