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Elimination of Hot Cracking in Laser Beam Welding
Author(s) -
Petzet Verena,
Büskens Christof,
Pesch Hans Josef,
Prikhodovsky Andrey,
Karkhin Victor,
Ploshikhin Vasily
Publication year - 2004
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.200410271
Subject(s) - cracking , welding , materials science , laser beam welding , beam (structure) , laser , ultimate tensile strength , displacement (psychology) , composite material , structural engineering , optics , engineering , physics , psychology , psychotherapist
Abstract Hot cracking is one of the big problems in laser beam welding. By multi‐beam welding, first suggested in the 70‐s (cf. [1], [4]), hot cracking can be avoided. Hereby two additional laser beams are employed. These beams generate a compression which compensate for the critical tensile strain in the solid‐liquid region of the weld induced by the main laser beam. However, hot cracking can only be prevented if the positions, sizes, and powers of the additional laser beams are suitably chosen, i.e. are optimized. Non‐optimal values can even enhance hot cracking. Until now these quantities have been found either by trial and error or by prescribing them intuitively. In the present paper a constrained nonlinear programming problem is formulated to solve the problem of hot crack initiation by minimizing the accumulated transverse strain, i.e. the opening displacement, in the solid‐liquid region. This approach is based on the so‐called strip expansion technique, cf. [2]. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)