CAJ | 학술논문

潜艇在潜浮过程中,由于静水外压引起的工作应力与焊接残余应力叠加,形成拉压循环应力,导致耐压船体的局部结构可能出现低周疲劳裂纹.一般情况下,高强度钢在抗拉强度提高的同时往往伴随着材料塑性储备和断裂韧性的下降,因此分析高强度钢潜艇结构的低周疲劳寿命非常重要.本文基于断裂力学和Paris公式建立了潜艇耐压结构低周疲劳寿命的工程估算方法,根据裂纹无损检测的概率统计和含裂纹圆柱壳极限应力分析,给出了初始裂纹和裂纹临界状态的建议值.应用本文的简化方法分析了某潜艇结构和锥柱结合壳模型的低周疲劳寿命,锥柱结合壳模型的数值算例表明本文的计算结果与试验测试结果相吻合.
잠정재잠부과정중,유우정수외압인기적공작응력여한접잔여응력첩가,형성랍압순배응력,도치내압선체적국부결구가능출현저주피로렬문.일반정황하,고강도강재항랍강도제고적동시왕왕반수착재료소성저비화단렬인성적하강,인차분석고강도강잠정결구적저주피로수명비상중요.본문기우단렬역학화Paris공식건립료잠정내압결구저주피로수명적공정고산방법,근거렬문무손검측적개솔통계화함렬문원주각겁한응력분석,급출료초시렬문화렬문림계상태적건의치.응용본문적간화방법분석료모잠정결구화추주결합각모형적저주피로수명,추주결합각모형적수치산례표명본문적계산결과여시험측시결과상문합.
The low-cycle fatigue induced crack propagation occurs in the structural details of submarine pressure hull when the applied stresses are superimposed on the residual welding stresses during its ascending and/or descending. It is important to assess the fatigue life for submarine pressure hull made of the high strength steel because the high strength steel presents a decrease in the material plasticity and fracture toughness with an increase of the tensile strength. In the present paper, a simplified approach is presented for low-cycle fatigue life prediction of submarine pressure hull based on the fracture mechanics and Paris law. The initial and critical sizes of cracks are proposed based on the statistics of the crack detection probability by non-destructive inspections and analysis results of the limit stress level of cracked cylindrical shell. The present method is employed to predict the fatigue life of a submarine pressure hull and experimental niodel of pressure conecylinder shell.The examples show that the results by the present method are in agreement with the experimental data of cone-cylinder model under cyclic external pressure.