小水线面双体船上层建筑结构疲劳强度试验研究

Fatigue strength test of a SWATH ship′s superstructure

针对小水线面双体船上层建筑下围与甲板连接处应力集中明显、疲劳强度问题突出的现象,本文基于谱分析法的全船疲劳强度分析结果,确定疲劳问题严重的部位,对常规腹板加强十字焊接型节点及采用肘板优化的一般焊接型节点分别设计了实板厚疲劳试验模型。通过疲劳试验获得了典型载荷工况下的疲劳失效循环次数,采用定斜率极大似然法及可靠性方法拟合S-N曲线,明确了优化前后2种节点的疲劳特性,验证了优化方式的有效性。试验结果对小水线面双体船的结构设计具有一定的借鉴意义。

The stress concentration is obvious in the connection area of the superstructure underside and the deck of the small waterplane area twin hull(SWATH) ship and the fatigue strength problem appears serious. Based on the spectrum analysis of the whole ship’s fatigue strength, the position was determined in this paper where the fatigue problems is serious.The real-thickness fatigue test models were designed including a conventional Web-stiffened cruciform welded joint and a general welded joint optimized with brackets. In the fatigue test, the values of the fatigue failure cycle times were obtained under the typical load conditions, and the S-N curves were drawn by fixed-slope maximum likelihood method and reliability method simultaneously. The fatigue characteristics of the two kind structure details before and after optimization were clarified, and the effectiveness of the optimization method was verified. The test result offers an important reference for the SWATH ship structure design.