考虑焊接初始缺陷的船体结构极限强度研究
发布时间：2018-08-13 16:13
【摘要】：对船体梁的纵向弯曲极限强度的准确评估是船舶结构设计的基本方面,焊接初始缺陷的存在会影响结构的刚度与极限强度。准确预测焊接后的残余应力与变形对极限强度的研究有重要的意义。本文将热弹塑性有限元方法与船体结构极限强度数值方法相结合,更加合理地考虑焊接初始缺陷对于船体结构极限强度的影响。为了进行理想剖面船体结构的极限强度分析本文主要进行了以下工作:(1)利用热弹塑性有限元法与具有截面积分的shell/solid单元模型进行板架纵骨焊接的温度场与应力场分析。在此基础上比较分析了不同边界条件对焊接变形与残余应力结果的影响。将板架周围的结构简化为加筋板的固定边界,更合理地反映板架中的纵骨焊接变形情况。(2)以理想舱段结构中的纵骨焊接作为研究对象,考虑结构周围材料对加筋板焊接模拟的影响,计算由焊接引起的残余应力和变形初始缺陷。(3)将理想舱段结构离散为加筋板单元与硬角单元,以加筋板单元为研究对象,采用非线性有限元方法进行极限强度分析。将热弹塑性有限元分析得到的焊接初始缺陷引入极限强度的分析中,比较有无初始缺陷以及不同的焊接分析边界对结构失效模式与极限强度的影响。得到筋板单元失效后包含后屈曲段的完整平均应力应变关系曲线,进行箱型结构极限强度的逐步破坏法分析。
[Abstract]:The accurate evaluation of longitudinal bending ultimate strength of hull girder is the basic aspect of ship structure design. The existence of initial welding defects will affect the stiffness and ultimate strength of the structure. Accurate prediction of residual stress and deformation after welding is of great significance to the study of ultimate strength. In this paper, the thermal elastoplastic finite element method is combined with the numerical method of the ultimate strength of the hull structure, and the effect of the initial welding defects on the ultimate strength of the hull structure is considered more reasonably. In order to analyze the ultimate strength of the hull structure with ideal section, the main work of this paper is as follows: (1) the thermal elastoplastic finite element method and the shell/solid element model with sectional area are used to analyze the temperature field and stress field of plate frame longitudinal bone welding. On this basis, the effects of different boundary conditions on welding deformation and residual stress are compared and analyzed. The structure around the plate frame is simplified as the fixed boundary of the stiffened plate, and the deformation of longitudinal bone welding in the plate frame is more reasonably reflected. (2) the longitudinal bone welding in the ideal cabin structure is taken as the research object. Considering the influence of materials around the structure on the welding simulation of stiffened plate, the initial defects of residual stress and deformation caused by welding are calculated. (3) the ideal cabin structure is divided into stiffened plate element and hard angle element, and the stiffened plate element is taken as the research object. The nonlinear finite element method is used to analyze the ultimate strength. The initial welding defects obtained by thermoelastic-plastic finite element analysis are introduced into the ultimate strength analysis to compare the influence of the initial defects and different welding analysis boundaries on the failure mode and ultimate strength of the structure. The complete average stress-strain relationship curve of the stiffened plate element including the post-buckling section after failure is obtained. The ultimate strength of the box structure is analyzed by the progressive failure method.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U661.43
本文编号：2181507
[Abstract]:The accurate evaluation of longitudinal bending ultimate strength of hull girder is the basic aspect of ship structure design. The existence of initial welding defects will affect the stiffness and ultimate strength of the structure. Accurate prediction of residual stress and deformation after welding is of great significance to the study of ultimate strength. In this paper, the thermal elastoplastic finite element method is combined with the numerical method of the ultimate strength of the hull structure, and the effect of the initial welding defects on the ultimate strength of the hull structure is considered more reasonably. In order to analyze the ultimate strength of the hull structure with ideal section, the main work of this paper is as follows: (1) the thermal elastoplastic finite element method and the shell/solid element model with sectional area are used to analyze the temperature field and stress field of plate frame longitudinal bone welding. On this basis, the effects of different boundary conditions on welding deformation and residual stress are compared and analyzed. The structure around the plate frame is simplified as the fixed boundary of the stiffened plate, and the deformation of longitudinal bone welding in the plate frame is more reasonably reflected. (2) the longitudinal bone welding in the ideal cabin structure is taken as the research object. Considering the influence of materials around the structure on the welding simulation of stiffened plate, the initial defects of residual stress and deformation caused by welding are calculated. (3) the ideal cabin structure is divided into stiffened plate element and hard angle element, and the stiffened plate element is taken as the research object. The nonlinear finite element method is used to analyze the ultimate strength. The initial welding defects obtained by thermoelastic-plastic finite element analysis are introduced into the ultimate strength analysis to compare the influence of the initial defects and different welding analysis boundaries on the failure mode and ultimate strength of the structure. The complete average stress-strain relationship curve of the stiffened plate element including the post-buckling section after failure is obtained. The ultimate strength of the box structure is analyzed by the progressive failure method.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U661.43
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