| Multi-point forming (MPF) is an advanced flexible manufacturing technique for sheet metal forming. Its basic principle is dividing the curved surface of the conventional solid die into a series of discrete elements , and the three-dimensional shape of sheet metal is formed by the envelope surface of the"element group". The position and movement of each element is controlled independently in real time by the computer. Adjusting the relative positions of the elements, it can easily shape the desired surface according to the design, and then the speedy and flexible sheet metal forming is realized. Comparing with the conventional die forming method, the MPF technique has saved a lot of time for die design, die manufacturing and debugging. It has shortened the exploiting cycle and reduced the cost. The MPF technology can be applied extensively in many fields, such as vehicles covered pieces, aircraft skin parts, hull panels of ship, pressure vessels, architectural panels, medical alloyed-rehabilitation of various shapes and so on.MPF process for sheet metal is a very complex mechanics process, simultaneity concerning nonlinear fields on geometry, material and boundary. Various forming defects happen on the process of MPF, and effect geometry precision, superficial quality and mechanism capability of parts. Numerical analysis method is an essential tool to optimize die design, predict forming defects and analyze forming quality. Among the Numerical analysis methods, finite element technology is the most efficient method. In recent years, it has been extensively applied in technical analysis of sheet metal forming, not only in the analysis of typical forming process, but also predicting dimples and cracks, calculating the magnitude of spring-back, improving the raw material design, and so on.On the process of multi-point stretch-forming, because the contacting condition between elements and sheet metal varies continuously and the load...
|
PDF Full Text Request