基于断裂力学的散货船外底纵骨疲劳寿命评估

摘要

基于断裂力学的疲劳裂纹扩展理论,按《散货船共同结构规范》确定疲劳载荷及计算工况,通过有限元应力分析对某散货船外底纵骨与横舱壁或横框架连接节点处进行疲劳寿命分析,并探讨了裂纹形状比对疲劳寿命的影响.研究结果表明,外底纵骨上远离横舱壁或横框架一侧的软趾端处的疲劳寿命比靠近横舱壁或横框架一侧的通焊孔焊缝趾端处的疲劳寿命要短,并且疲劳寿命随着裂纹形状比的增大而增大.%In order to assess fatigue life reasonably, fatigue crack propagation theory based on fracture mechanics is applied to a bulk carrier in this paper. According to the standard "Common Structural Rules for bulk carriers", fatigue loading and carrier loading conditions are decided. Fatigue life of the juncture of bottom longitudinal of bulk carrier and frame transition or transverse bulkhead is analyzed based on the result of FEM stress analysis, and the effect of the crack shape ratio on the fatigue life is investigated. Furthermore the fatigue life of soft toe which is far from frame transition or transverse bulkhead is significantly shorter than that of clearance hole toe which is near frame transition or transverse bulkhead, as well as fatigue life is increased with the increase of crack aspect ratio.