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原文传递 FINITE ELEMENT MODELING OF RESIDUAL STRESSES IN ELECTROSLAG BUTT WELDS.

题名：	FINITE ELEMENT MODELING OF RESIDUAL STRESSES IN ELECTROSLAG BUTT WELDS.
作者：	Atteridge-D; Becker-M; Khan-K; Meekisho-L; Tahmasebi-B; Zhang-L
关键词：	Bridges-; Deformation-curve; Electroslag-welding; Finite-element-method; Mathematical-models; Residual-stress; Steel-; Stress-distribution; Three-dimensional-models; Two-dimensional-models; Weldments-
摘要：	Shop fabricated electroslag (ES) welds used in bridge construction have had a history of low toughness in the fusion and heat affected zones. In addition, conventional inspection of ES weldments under shop fabrication conditions fail to consistently detect and/or correctly size weld discontinuities. These problems have led to a Federal Highway Administration requirement for removal, re-enforcement, or re-evaluation of the integrity of ES weldments in existing Federal bridges. This study was initiated in partial response to this requirement by the Oregon Department of Transportation. The specific tasks of this study were: a) to develop an understanding of ES weld-induced residual stresses for A36 steel with an emphasis on assessment of bridge-specific weld parameters and residual stress measurement; and b) computational modeling of ES welding (ESW) and the resultant stress distribution. The ES weldments assessed in this study were those used in the fabrication of the Oregon State I-205 West Linn Bridge. This research was performed by numerical modeling based on unknown welding operation parameters. Experimental assessment of fusion zone characteristics was used as input data for the computational modeling work. Selective etching techniques were used to reveal the solidification bands formed at the fusion line interface during ESW. Analysis of these solidification bands allowed determination of weld pool profiles formed during welding, which are a direct function of the welding parameters. The results indicated that the operation procedures for all of the assessed ES welds were nominally the same. Two-dimensional (2D) and three-dimensional (3D) models were developed using finite element analysis (FEA) methods to simulate the ESW process and to analyze the effect of operating conditions on residual stress distribution. Both Lagrangian (stationary) and Eulerian (moving) coordinate systems were assessed in the FEA. Modeling using Eulerian coordinates was found to be over 100 times more efficient than Lagrangian coordinates. Thus all 3D thermal-mechanical modeling was done using Eulerian coordinates. Both 2D and 3D thermal heat transfer ESW FEA models were developed using the Lagrangian system; only 3D thermal models were developed using the Eulerian coordinate systems. The thermal modeling effort included accounting for the latent heat of solidification. All 3D model results were in agreement, and agreed with experimentally determined ESW-induced thermal histories previously measured at the Oregon Graduate Institute. The weld-induced transient temperature fields predicted by the thermal heat transfer models were used as input into the Lagrangian Coordinate 2D mechanical 2D analysis and into
总页数：	2000/03. pp146 (Figs., Tabs., 75 Ref., 3 App.)
报告类型：	科技报告