The underwater wet welding method for repairing of submerged structural members has been intensively developed during the last years. It is an economical and especially more time-independent procedure. The shortened repair duration is a major advantage in regions with rough sea climate as the North Sea area. During research projects the weldability and fatigue performance of pipe-patch connections have been tested. These joints are in use for repairing of collision indents. The shape of the actual used repair patch was optimised to the requirements of under water wet welding at high tensile steels as BS4360 Gr 50D. Steel materials in this grade show problems in regard to high hydrogen susceptibility and therefore cold cracking. The fatigue behaviour of the patch-welded pipe structural member has been investigated. First test series were carried out using as welded joints. In a second part of the project post weld treated connections were tested. The weld seams on these joints were partially ground or hammer peened. The test results have been evaluated by means of the hot-spot concept and then faced with actual code requirements. Extensive strain gage measurements and Finite-Element calculations have been carried out to provide the stress state in the structural details.
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机译:用于修复浸没式结构构件的水下湿焊方法在过去几年中被密集地发展。这是一个经济且特别是无关的程序。缩短修复持续时间是作为北海地区粗糙海洋气候的地区的主要优势。在研究期间,已经测试了管道连接的可焊性和疲劳性能。这些关节用于修复碰撞缩进。实际使用的修复贴片的形状被优化到高拉伸钢下的水湿焊接的要求作为BS4360 GR 50D。该等级中的钢材显示出高氢气易感性和冷裂化的问题。已经研究了贴片管结构构件的疲劳行为。第一个测试系列使用作为焊接接头进行。在项目的第二部分中,焊接后处理的连接进行了测试。这些接头上的焊缝部分地研磨或锤子喷丸。通过热点概念评估了测试结果,然后面临实际的代码要求。已经进行了广泛的应变计测量和有限元计算,以在结构细节中提供应力状态。
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