The non-uniform distribution of the mechanical properties of welded tube would affect the plastic deformation behavior of tube during the free bending process. To explore the influence of weld position on the forming quality and axis dimensional accuracy of welded tube, the free bending experiment and numerical simulation of welded tube were conducted in this paper. First, the principle of free bending was theoretical deduced and the stress distribution of bent tube was analyzed. Then the hardness test and uniaxial tensile test were conducted to obtain the mechanical properties of weld zone and parent zone of welded tube. The material strength in the weld zone of welded tube is significantly higher than that in the parent zone.Finally, the free bending experiment and numerical simulation with different weld position were carried out, and the influence of weld position on the bending radius, cross-sectional distortion and wall thickness of bent tube was discussed. All these findings advance the insight into the free bending deformation behavior of welded tube and help to improve the forming quality of welded tube and facilitate the application of free bending technology in welded tube.

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The non-uniform distribution of the mechanical properties of welded tube would affect the plastic deformation behavior of tube during the free bending process. To explore the influence of weld position on the forming quality and axis dimensional accuracy of welded tube, the free bending experiment and numerical simulation of welded tube were conducted in this paper. First, the principle of free bending was theoretical deduced and the stress distribution of bent tube was analyzed. Then the hardness test and uniaxial tensile test were conducted to obtain the mechanical properties of weld zone and parent zone of welded tube. The material strength in the weld zone of welded tube is significantly higher than that in the parent zone. Finally, the free bending experiment and numerical simulation with different weld position were carried out, and the influence of weld position on the bending radius, cross-sectional distortion and wall thickness of bent tube was discussed. All these findings advance the insight into the free bending deformation behavior of welded tube and help to improve the forming quality of welded tube and facilitate the application of free bending technology in welded tube.

This paper introduces a new double-wall fabricated steel insulation silo with multiple bolted joints. The software ANSYS is utilized to model a 1000-ton double-wall fabricated steel insulation silo with multiple bolted joints and calculate its stress and displacement. The silo is optimized by adjusting the wall thickness of the silo. The model which uses the original thickness is defined as Model 1. The optimized model is defined as Model 2. The stress and deformation of these two models were comparatively analyzed. The results show that the maximum stress and the maximum displacement of Model 2 are both smaller than the specified values. Furthermore,it saves about 40.7% with the steel quantity compared with Model 1.

<p>In Japan, bolted patch plate method is often used for repairing the steel member with a fatigue crack on the bridge. However, it is not clear that how to arrange bolted patch plate for repairing fatigue clack rationally and effectively. In this paper, study aims to investigate the influence of bolted patch plate arrangement for fatigue strength considering that the bolted patch plate has been slipped by a severe earthquake.</p>