Numerical simulation of edge effect in plasma arc forming of sheet metal
Edge effect was found in plasma arc forming process of sheet metal, which reduces the forming accuracy of sheet metal seriously. In order to reveal the forming mechanism and forming laws of the edge effect. A numerical model on forming of sheet metal using plasma arc with scanning along a straight line was established and the forming mechanism and forming laws of the edge effect were studied. The results showed that the upper material and the lower material of the edge were produced shrinkage along the scanning path and both shrinkage were different. The size relationship of the two shrinkage determines the direction of edge warp. The difference of the two shrinkage affects the warpage of the edge. In the comprehensive effect of shrinkage and warpage, the non scanning region in the both sides of the scanning path appears bulge or depression. The numerical analysis results were agree well with the experimental results. The conclusions provide a theoretical basis to reduce the effect of the edge effect on the accuracy of the sheet metal forming.
Numerical and Experimental Study on Flexible Froming the Circular Arc of Sheet Metal Using Plasma Arc
Flexible forming the circular arc of sheet metal using plasma arc can be formed by combing V-shape bending,and also the geometrical relationship between circular arc bending part and V-shape bending part is investigated.In this paper,the authors advanced the relationship between a parameter γ and the degree of circular arc smoothness firstly.A simulation program for flexible forming the circular of sheet metal using plasma arc was programmed by the ANSYS Parametric Design Language(ADPL),and the experiments were done.The results show: When γ=0.1~0.2,the forming circular arc is very smoothness.Good correlation between the numerical simulation the experimental results.is achiered.
Finite element modeling of laser forming
The ability of a laser beam to heat metal sheets and establish local thermal gradiants allows the thermo-mechanical forming of complex shapes. Thermal gradients can be developed locally through the thickness direction and laterally in constricted areas. The modeling of the simplest laser forming, a fold produced by the motion of a laser beam spot along a linear path bisecting a square sheet, has been accomplished with finite element thermal and mechanical modeling. The code ABAQUS was used at M.I.T. and the combined codes TOPAZ3D/NIKE3D were used at Boeing. Melting was avoided in the tests on a number of metals and the modeling was done for conditions below melting, but the properties of the metals at elevated temperatures were not completely known. Modeling has predicted the observed spatial distribution of transient motions for the forming process that occurs during and after the laser processing. The final folding angles have been predicted and compared with measured results.The ability of a laser beam to heat metal sheets and establish local thermal gradiants allows the thermo-mechanical forming of complex shapes. Thermal gradients can be developed locally through the thickness direction and laterally in constricted areas. The modeling of the simplest laser forming, a fold produced by the motion of a laser beam spot along a linear path bisecting a square sheet, has been accomplished with finite element thermal and mechanical modeling. The code ABAQUS was used at M.I.T. and the combined codes TOPAZ3D/NIKE3D were used at Boeing. Melting was avoided in the tests on a number of metals and the modeling was done for conditions below melting, but the properties of the metals at elevated temperatures were not completely known. Modeling has predicted the observed spatial distribution of transient motions for the forming process that occurs during and after the laser processing. The final folding angles have been predicted and compared with measured results.