点蚀损伤船体板格单轴压缩极限强度

Ultimate Strength of Ship Structural Plate with Pitting Corrosion Damnification Under Uniaxial Compression

为了能够简单准确地计算服役期内点蚀损伤船体板格的极限强度，选择腐蚀体积为点蚀损伤板的主要评估参数，结合实际船体板格的腐蚀损伤特点，采用有限元数值计算方法，分析点蚀坑形状、有限元单元类型、蚀坑分布和蚀坑深度对板极限强度的影响，以及板的初始柔度、初始变形、长宽比和板边缘线性载荷因子对板极限强度折减因子的影响，并利用回归分析方法，建立了基于腐蚀体积的点蚀损伤船体板格极限强度折减因子的计算公式．结果表明，整套公式的计算结果与有限元计算结果的相对误差仅有极少量在5％～6％之间，绝大部分在5％以内，可用于服役期内点蚀损伤船体板格的安全评估．

To simply and accurately calculate the ultimate strength of ship structural plates with corrosion damnifica- tion during the service lives of ships, the corrosion volume loss was used as the most important assessment parameter of the plate with corrosion damnification. On the basis of the characteristics of the actual hull structural plates, the effects of some parameters （the shape of pits, the type of finite elements, the distribution of pits and the depth of pits） on the ultimate strength and the effects of some parameters （the initial slenderness, the initial geometric deflec- tion and the aspect of plates and the linear load factors at the plate edges） on ultimate strength reduction factor were studied by the nonlinear finite element analyses. The ultimate strength reduction factor formulae based on the corro- sion volume loss were obtained by regression analysis approach. The results show that most of the relative errors be- tween the calculating value by the formulae and finite element analysis result are below 5% and only very few is 5% --6%. The formulae can be used in the safety assessment of ship structural plates with pitting corrosion damnifi- cation during their service lives.