Papers by Author: Ying Wu Lan

Abstract: In order to manufacture a three dimensional sheet metal part effectively, a continuous sheet metal forming process (CSMF) based on flexible roll bending has been proposed and developed. This paper mainly focuses on the fundamental aspects of the process, the principle of CSMF is introduced and the method to estimate the downward displacement of upper roll based on the desired curvature of the deformed sheet metal is presented. The variation of the upper rolls downward displacement with the desired bend radius is shown in graphically. The smoothness of the CSMF parts was measured and analyzed. In the results, it is shown that a three-dimensional sheet metal part can be formed without defects and the formed surfaces are in good agreement with the target shapes.

Abstract: In this paper, an analytical solution for the three-roll bending process of thin-plate was presented. Based on the theoretical analysis on continuously loading and unloading deformation of the plate during roll-bending, the curvature equations governing the bending behavior of thin-plate were set up and then solved by integration. Combing the solutions with the geometrical relationships in three-roll bender, the deflection and bending angles occurring during the steady continuous bending period were obtained by an iterative scheme. Numerical examples were given to illustrate the application of the solutions. The variation of the top roll’s position with the intended bend radius, the curvature and deflection distributions on bent plate were shown in graphically and discussed.

Abstract: The analytical solutions for the deformations of straight-ends in three-roll bending process of thin-plate were presented. Based on the theoretical analysis on the loading and unloading during roll-bending, the curvature equations governing the bending behavior of thin-plate were set up and then solved by integration. Numerical examples were given to illustrate the application of the solutions. The curvature and deflection distributions on straight-ends were shown in graphically and discussed.

Abstract: The deformation of sheet metal in the continuous flexible forming (CFF) process is complex and the formed result is affected by many factors. In this paper, the finite element model of CFF was founded and the forming processes of spherical parts were simulated with the software ABAQUS. The interaction between transversal deformation and longitudinal deformation in the CFF process is analyzed. Based on results of numerical simulation and forming tests, the process parameters of CFF is revised, and formed surface is measured by three dimensional sensing system, the measured results indicate the precision of formed parts are satisfactory.

Abstract: As a flexible manufacturing technique, Multi-point stretch forming (MPSF) is a suitable method for forming aircraft outer skin part. The traditional solid stretching die is replaced by the discrete multi-point die (MPSD), and the sheet metal is stretch-formed over the MPSD generated by serial adjusting mode or parallel adjusting mode. The MPSF can be used to form the parts of different shape and reduce the cost and leading time of stretching die fabrication for aircraft outer skin part. A series of numerical simulations on typical MPSF processes of aircraft outer skin part were carried out. The thickness of elastic cushion and free length are important factors to influence on the stretch forming results of stretch-formed parts. The numerical simulation results show that the thicker the elastic cushion is, the more valid the dimple will be suppressed .The longer the free length is, the easier the wrinkle will be brought.