Profiles’ Stretch-bending Research Of Variable Curvature Based On Iterative Compensation Mechanism

As we all know, products by stretch-bending are provided with advantages of high accuracy and good surface quality, so they are widely used in shipbuilding, automotive,mining, aerospace and other manufacturing industries. At present, the studies of profiles’ stretch-bending process are mostly equal curvature deformation, and many research achievements point out methods to calculate accurately the amount of springback and effective measures to reduce springback. However some stretch-bending forming parts of special structure are variable curvature, such as cars’ frames and aircraft’s structure. It’s rarely discussed in the current stage of research for such variable curvature stretch-bending process’ study of springback and compensation.This paper discussed a method of using finite times compensation operation to make products’ size achieve expectations——Iterative Compensation Mechanism,aiming to base on the foundation of improving this method to prove the iterative convergence of a variety of bending process, and focused on demonstration of the method used in the stretch-bending process of variable curvature.The convergence of mechanism was proved theoretically,and the iterative method gave quantitatively amount of compensationThis paper started from the test results of V-type bending, combining with iterative root finding method of the equation in “Numerical Analysis”, put forward the Iterative Compensation Mechanism, and proves the iterative convergence of common bending process from the view of mathematical methods; against the metal sheet’s uniaxial stretch deformation, ordinary free bending process, ordinary stretch-bending process, pointed out the iterative parameters, and prove its convergence; it discussed simply the theory basis of variable curvature stretch-bending process. Against the stretch-bending deformation’s mold surface of quadratic function curve and cubicfunction curve, it chose the shape parameter “a” of the equation as the iterative parameters, and proved its iterative convergence.The numerical simulation software ABAQUS was applied to establish models of the stretch-bending process’ mold surface of quadratic function curve and cubic function curve, and simulate individually the actions of iterative compensationbased on Iterative Compensation Mechanism. The simulation results showed that both of the two variable curvature stretch-bending processes’ iterative parametric “a” could be close to the target with high accuracy after limited times compensation operation.At last, feasibility of the variable curvature stretch-bending compensation processes of the two kinds mold surface was proved through experiments, and different materials slabs were selected to explain that Iterative Compensation Mechanism has the general characteristics of not depending on the material properties and mechanical models.