Research On Thickness Variation With U-bend Forming Of The Wide Sheet Of Aluminum Alloy

The process to press the sheet metal into various angles, curvatures and shapes is calledbending. Bending is one of the forming processes, which has a wide application and occupiesa prodigious proportion in stamping production. Bending deformation exists in many otherforming processes also, which is widely used in various fields of the metal working industry,and it plays a crucial role in the industries for railway, manufacturing automobiles,instruments, military parts and household electrical appliances, etc. So it has greatsignificance to master the forming characteristics and deformation rules of bending.The materials used for sheet bending include mild steel, copper, aluminum, magnesiumalloy and high-plasticity alloy-steel, etc. As the development of high-speed railway all overthe world especially in China, the lower weight of the body has become one of the mainmethods of raising train speed. Because of its high strength, low weight and other advantages,aluminum alloy sheet are widely used in high speed train body member and the interiordecoration parts. This requires the aluminum alloy bending forming performance to meet thehigher requirements. In the previous discussion, the study only focused on the problem ofaluminum alloy bending spring-back, for the bending process of thinning phenomenonresearch less. In this paper, we study the law based on simulating model test, theoreticalanalysis and experimental verification. On the basis of the previous research, we do theresearch on thickness variation with U-bend forming of the wide sheet of aluminum alloy.Through the characteristics of the stress neutral layer that stress in radial directioncontinuous in the process of bending, we derived the calculation formula of the thicknessduring the bending process, and get the theoretical data. Through the simulation of bendingprocess which is used the sheet metal forming analysis software DYNAFORM, we draw theinfluential factors, trend and thinning location of the plate thickness reduction. It is providethe reference for the experimental study and design of the bending die. Finally, through thetest, we analysis of the effect of material properties (include the elastic modulus E and Rvalue), material thickness, roundness radius of punch, clearance between punch anddie, coefficient of extension and the pressing speed on bending thinning. Wemeasured the test thinning data during the sheet bending process and prove the correctness ofthe theoretical analysis through the theoretical and simulation analysis. We obtained theinfluence of the factors and the law about the aluminum alloy sheet bending thinning.