Thermal Tensioning Effects to Prevent Welding Buckling Distortions in Manufacturing of Thin-Walled Aerospace Shells and Panels

摘要

To prevent buckling distortions of thin-walled elements, Low Stress No Distortion welding techniques have been pioneered and developed for product engineering and component manufacturing of aerospace structures with material thickness less than 4 mm. In this paper, the nature of Low Stress No Distortion (LSND) welding techniques using thermal tensioning effects is described and special emphases are given to the mechanism of localized thermal tensioning effect. The fundamental principle of Low Stress No Distortion welding is to create active in-process control of incompatible (inherent) plastic strains and stresses formation during welding to achieve distortion-free results implying that no post weld costly reworking operations for distortion correction is required. Finite element analysis is applied to predict and optimize the localized thermal tensioning technique with a trailing spot heat sink coupled to the welding heat source. Comparisons of the thermal elastic-plastic stress-strain cycles are given between conventional gas tungsten arc welding and GTAW with a trailing spot heat sink.