摘要：
船用加筋板极限强的有限元计算方法应用广泛,但其计算方法具有一定的不稳定性,计算结果受多种因素的影响.本文针对加筋板有限元计算方法的不稳定性进行研究,通过将有限元计算结果与其他学者的研究成果进行对比,验证了本文所采用的有限元方法的可靠性,然后针对加筋板材料、边界条件、网格密度、初始缺陷等几种因素的敏感性进行了具体的研究,发现使用材料的理想应力应变关系得到的计算结果偏于危险,且误差最大可达到17％左右,网格的形状和疏密程度对结果均有影响,边界条件若不考虑横向加强构件的作用,所得计算结果不准确,初始缺陷对有限元结果影响复杂,需要根据加筋板的实际缺陷选取适合的屈曲模态.%The stiffened plate is the basic structure of the hull,when it is subjected to compression,shear,bending,torsion,etc.often destroyed by buckling.When the stiffened plate is subjected to axial compression load,The instability process generally consists of two stages:the initial buckling deformation stage and the post-buckling deformation stage.The ultimate loading strength occurs in the post-buckling,Therefore,it is of great significance to study the bearing capacity curve of the buckling of stiffened plate.The finite element method of ship stiffened plate is widely used in marine structure design,but it is instable in some degree.Calculation results are influenced by many factors.In this paper,the instability of the finite element method is studied.the results of finite element method are compared with the results of other scholars.The reliability of the finite element method used in this paper is verified.Then,the sensitivities of several factors,such as the material parameters,the boundary conditions,the mesh density,and the initial defects,are studied.Many calculations is found,firstly,the ideal stress-strain relationship and the real stress-strain relation are studied in this paper,It is found that the ultimate strength value calculated by the ideal stress-strain relation is more dangerous than the calculated value of the real stress-strain relation,the error is about 17％,it is the more sensitive element in finite element method.Secondly,based on the calculation results of model 1 and model 3,the calculation results of lateral strength component in boundary conditions are more accurate,In comparison,the calculation result of model 2 is 7 ％ error,and there is no convergence problem,which indicates that the lateral boundary condition cannot be ignored to support the stiffened plate,Otherwise,the premature buckling of local plate or reinforcing rib will result in small calculation results.Thirdly,under the rough mesh,the width ratio of the unit is increased and the ultimate strength is decreased,If the mesh divided by a certain principle,at least five units in a half buckling wavelength,the mesh shape is close to the square,in this principle,the mesh is encrypted twice,which has little influence on the result and less sensitivity.Fourthly,the function of proportional factor is to scale the characteristic buckling mode according to certain ratio,post-buckling mode was introduced into the post-buckling analysis,the gap between the results was 10％.It is indicated that the value of proportional factor has a great influence on the calculation result,and its value should be selected according to actual size of imperfection by the experimental model.
