Finite element simulation of 3-D laser forming by discrete section circle line heating

Abstract

Laser forming of sheet metal is the bending process, induced by thermal stress, which is produced in the sheet by laser irradiation. Laser forming of complex shapes requires the study of the effect of various irradiation paths. In this paper the deformation of a circular plate, subjected to a circular irradiation path, is studied through a sequentially coupled thermomechanical elasto-plastic simulation by finite element method. The quality of laser bending in terms of waviness parameters, e.g., waviness average, R a , RMS value, R q , etc. are reported in detail, with respect to number of sections and number of passes of heating, as well as, shifting of the starting point for irradiation. It is observed that discrete section heating in symmetry with shifting in starting point of irradiation in subsequent passes reduces the undesired waviness, which is caused, otherwise, due to continuous circular heating.

Finite element modelling of substrate thermal distortion in direct laser additive manufacture of an aero-engine component

“…The immense temperature gradient along with the edge constrains and circular track heating have the potential to cause large residual stress and deformation through coupled buckling and temperature gradient mechanisms. 33 –36

Figure 6. Deposition and vertical Z -displacement (in mm) profile of the aero-engine component with time.

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Lasers Based Manufacturing

“…However in many cases, work parts with complex or spatially curved geometries like spherical dome or ship hulls are required. Venkadeshwaran et al (2010) studied the deformation of a circular plate subjected to a circular irradiation path with shifting of starting point. In such cases, instead of straight line, curvilinear irradiations are found to be more convenient and efficient .…”

Numerical Simulation and Experimental Validation of Sheet Laser Forming Processes Using General Scanning Paths

“…Hennige [ 17 ] conducted an experimental study on the behavior of the plates subjected to curve laser irradiation paths to generate spherical dome samples, comparing the final shapes obtained with different plate geometries. Venkadeshwaran [ 18 ] numerically simulated the deformation of a circular sheet using circular laser scans to propose strategies to reduce the waviness in the plate through its division into sections, which are irradiated in a certain order. Safari and Farzin [ 19 ] performed an experimental work in which a laser scanning sequence with a spiral irradiating scheme to generate a saddle shape was proposed and assessed in terms of the effect of the pitch in the spiral path, the number of spiral paths, and its direction (in-to-out and out-to-in spiral paths) on the final shape.…”