Authors: Peter Marshall Xudong Qian C T Nguyen Y Petchdemaneengam
Publish Date: 2013/05/03
Volume: 57, Issue: 4, Pages: 569-579
Abstract
This paper will present the experimental and numerical investigation on the fatigue crack failure at the root of the enhanced partial joint penetration welds in the circular hollow section Xjoint specimens subjected to constantamplitude brace inplane bending actions The enhanced partial joint penetration welds which include a portion of the brace wall as the inherent “backplate” for the welds reduce the workmanship requirement on the welding procedure and improve the quality control of the welded joint This study compares the fatigue crack developments observed at both the weld toe and the weld root in three largescale Xjoint specimens with different postweld surface treatments Root cracking does not take place in aswelded tubular Xjoint specimens of which the fatigue life depends on the weld toe failure In specimens with postweld grinding treatments to enhance fatigue resistance of the material near the weld toe however the finitelength root face triggers the initiation and propagation of fatigue cracks with an applied number of cycles more than that required to initiate a toe crack in the same tubular Xjoint Ultimate strength testing of specimens with large fatigue cracks and posttest sectioning reveals that fatigue failure weldtoe fatigue cracks remain more critical than the root cracks
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