局部腐蚀下耐压船体结构振动特性及稳定性研究

摘要

To explore the bearing characteristics of pressure cylindrical shell with local corrosion, the vibration characteristics and stability of ring stiffened cylindrical shell with local corrosion under uniform deep water pressure are studied.The vibration characteristics and critical loads due to different corrosion parameters are investigated.A series of finite element analyses for corrosive structure with different corroded areas, positions, and depths is constructed by using NASTRAN.Then the vibration characteristics and instability modes are presented.It is shown that the local vibration mode arises and the corresponding natural frequency decreases monotonously when the corroded depth is more than 3 mm.The square of first natural frequency of the ring stiffened cylindrical shell with local corrosion has a three-linear relationship with the hydro-static pressure when subjected to deep water pressure.The critical load remains unchanged when the corrosion depth is less than 2 mm while it decreases immediately when the depth is more than 2 mm.%为探究局部腐蚀下耐压圆柱壳的承载特性,在均匀深水压力作用下,针对具有局部腐蚀的环加筋圆柱壳的振动特性及稳定性进行了研究,分析了腐蚀参数对振动特性与临界失稳载荷的影响.通过改变腐蚀面积、腐蚀位置和腐蚀深度,利用有限元软件NASTRAN进行系列仿真分析,得到了含有局部腐蚀环加筋圆柱壳结构的振动特性及失稳破坏模式.结果表明:当腐蚀深度大于3 mm时,结构开始出现局部振动模态且固有频率单调下降;静水压力作用下带有局部腐蚀的环加筋圆柱壳一阶固有频率的平方与静水压力呈三段线性关系;在临界载荷方面,当腐蚀深度小于2 mm时其对结构的临界失稳载荷几乎没有影响,当腐蚀深度大于2 mm时临界载荷随即减小.