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.