【作者】 曲先强；

【导师】 石德新；

【作者基本信息】 哈尔滨工程大学 ， 船舶与海洋结构物设计制造， 2003， 硕士

【摘要】 现行的“潜艇结构设计计算规则”中关于疲劳强度的设计，是按照极限下潜次数不超过500次的标准进行校核。由于新的高强度钢材料的使用，和结构设计发展的需要，潜艇结构的疲劳强度问题更加突出，现行设计规范已经不能满足设计的要求。 裂纹闭合现象普遍的存在于金属材料的疲劳裂纹扩展过程中，对裂纹扩展有着重要的作用。本文将基于裂纹闭合现象建立的带状屈服模型，用在平面贯穿裂纹中，计算此时的裂纹张开应力和疲劳裂纹扩展寿命，与试验结果和经验公式比较，验证Newman裂纹张开应力理论在高强钢中的可行性；然后，用切片合成法，把潜艇结构凸锥柱结合壳焊缝处的三维表面裂纹分解成平面贯穿裂纹，用带状屈服模型的理论来分析平面贯穿裂纹，得到裂纹沿深度方向的扩展速率，进而得到潜艇结构的疲劳寿命。 基于带状屈服模型的数字仿真方法在航空航天结构上已经开展运用，但尚未用于潜艇结构疲劳断裂问题。本文把疲劳裂纹闭合模型通过切片合成法引入到潜艇结构疲劳强度计算上来，建立了潜艇结构疲劳强度的数字仿真计算的数学模型，分析该方法在潜艇结构疲劳强度计算上应用的可行性，为建立一套计算和设计潜艇结构疲劳强度的方法作了初步的探讨。更多还原

【Abstract】 The using rules about the fatigue strength in "Design and Calculation Standard for Submarine Structure" is worked out according to the standard that the ultimate time of submergence is less than 500. With the using of high strength steel and the development of the structure design, the fatigue strength becomes more and more prominent and the rules of design can no longer meet the demand of the design nowadays.The phenomenon of crack closure, which is important for the crack growth, is widely existed in the progress of fatigue crack growth in the metal materials. The strip-yield model based on the crack closure is used in the plane through cracks. The opening stress and the life of crack growth is calculated and compared with the test results and the experience formula. The feasibility of the Newman theory of opening stress used in the high strength steel is validated. Then through the slice synthesis method, the three dimension surface crack of the weld joint of cone-cylinder is decomposed into many plane through cracks. The strip-yield method is used to analyze those plane through cracks. Then the crack growth velocity is acquired, and the fatigue life is gotten too.The numerical simulation method based on the strip-yield method has begun to be used in the air space structures, but not used in the fatigue questions in the submarine. The numerical simulation technique is used to study on the fatigue properties of submarine with high strength steel. The numerical simulation model is established and its feasibility is validated. At last, the possibility of establishing a kind of calculation and design methods of fatigue life in submarine structure is primarily analyzed.更多还原