The ferry - borges load combination method is applied to combine the stochastic processes of stillwater and wave bending moments , and the failure of ship hull girder occurs when the combined value of stillwater and wave bending moments exceeds the first yield bending moment 另一方面，船舶在服役期内要定期接受检验，一旦发现船体构件严重受损，则要对其进行修理。遭受损伤的构件在维修后能恢复其对船体强度的贡献，从而提高船体梁的可靠性水平。
It shows that the degradation effects of fatigue and corrosion have important influence on the safety of ship structure , especially after the ship has put into service for 10 years . and the detailed inspection should be done at this time to maintain the reliability level of ship hull girder 计算结果表明：疲劳裂纹和环境腐蚀在船舶服役10年之后对船体梁可靠性有显著的影响，此时开展详细的船体结构检验对保证船舶营运的安全性具有重要意义。
If not , increase the curvature , and redo the above steps until get the ultimate strength . in the thesis the author analyzes the tripping of stiffened panels by three different methods . based on the above method , the author calculates the ultimate longitudinal strength of a boxlike girder , several ships and many stiffed panels by program 当船体梁在中拱或中垂状态下时，假定一个初始曲率，累积各个单元对瞬时中和轴的弯矩，然后判断弯矩是否达到极限，如未达到，则增加曲率，重复上述过程，直至弯矩为极值。
Since the overall failure of a ship hull is normally governed by buckling and plastic collapse of the deck , bottom or sometimes the side shell stiffened panels , it is of crucial importance to accurately calculate the ultimate strength of stiffened panels in deck , bottom and side shell for more advanced structural design of ship structures 由于船体梁的总体破坏通常由甲板、底板或者舷侧加筋板的屈曲或塑性破坏控制，因此在船舶结构设计中准确地计算甲板、底板或舷侧加筋板的极限强度就显得尤为重要。
Abstract : the time - variant reliability analysis of ship hull girders subjected to the deg r adations of fatigue and corrosion is quantitatively carried out in this paper . th e analytical formulations are derived and simple program is compiled . as a case s tudy , the time - variant reliability of a vlcc tank is calculated . it shows that th e degradation effects of fatigue and corrosion are very important for the load - c a pacity calculation of thsip hull girders . after the second special inspection ( 10 years ) , the detailed inspection should be done in order to guarantee the safety of ship navigation 文摘:定量考虑船体构件疲劳裂纹扩展和环境腐蚀对船体梁承载能力的双重衰减因素的影响，对船体梁的时变可靠性进行了分析，列出了时变可靠性分析公式并编制了相应的计算程序.以一艘大型油船的结构可靠性为例，表明疲劳裂纹和环境腐蚀在第二个特检年( 10a )之后对船体梁承载能力有显著的影响，此时开展详细的船体结构检查对保证船舶营运的安全性具有重要的意义
The plating in ships is generally subjected to combined in - plane and lateral pressure loads . in - plane loads include biaxial compression / tension and in - plane bending and edge shear , which are mainly induced by overall hull girder bending and / or torsion of the vessel . lateral pressure loads are due to water pressure and cargo 面内载荷分为轴向压应力或拉应力、边缘剪切应力以及面内轴向弯曲应力。实际的船舶结构中面内载荷通常由船体梁的总纵弯曲或者船体梁的扭转引起。侧向压应力则由水压力和货物压力引起。
On basis of ship strength theory , mathematical model and solvable method of limited deflections of ships are established , and deflection criterion to check the demands of longitudinal strength of intact ships or damaged ships is proposed . it is convenient for the preliminary ship design 根据船体梁强度理论，建立船舶极限挠度数学模型与求解方法，提出利用船舶挠度检验船体总纵强度的新方法，可以较方便地对正常或破损船舶总纵剩余强度进行检验，便于初步设计。
A time - variant reliability formulation is presented in this paper to account for the effects of fatigue , corrosion and maintenance actions on the first yield reliability of midship section modulus . a probabilistic model for long - term distribution of wave - induced fatigue stress range is established . for the purpose of obtaining the performance of structure that stands random fatigue load , the concept of stress parameter and equivalent stress range are introduced 船舶在由波浪弯矩引起的交变应力作用下，船体构件焊接点处的微小裂纹逐渐扩展；同时，随着船龄的增加，众多结构构件遭受腐蚀的作用；从而使船体梁剖面模数减小，船体梁承载能力衰减，船舶结构的安全性将受到相当大的影响。
Firstly , it needs to separate the girder hull into many elements - pulled one and pushed one . secondly , when the ship is in hogging or sagging , you should assume one curvature value so you can get the moment value of every element at this curvature . and then you may add up all the moment of every element 当船体梁在中垂或中拱状态下时，假定一个初始曲率，根据各个单元对瞬时弹性中和轴弯矩的贡献，累加得到相对于这个曲率的总弯矩，然后判断弯矩是否达到极值，如未达到，则增加曲率，重复上述过程，直到弯矩为极值为止。
This thesis used along caldwell ' s direct calculation method of the ultimate strength of ship hull girders , considered the double bottom and upperwing tank to ship ultimate strength contribution , first defined the stress distribution of the whole section of the ship girders . that is : in the sagging condition , deck and side shell of nearby deck remain the ultimate bucking strength , double bottom remain the yield stress . and the other parts keep elasticity 本文沿用caldwell等人直接计算船体极限强度的思想，考虑双层底和顶边水舱对船体极限强度的贡献，首先将船体梁整体破坏时剖面应力分布确定为：在中垂状态下，甲板及甲板附近的舷侧均屈曲，双层底区域则均屈服，其他部分保持弹性状态；在中拱状态下，双层底及之间的底舷侧均屈曲，甲板及顶边水舱区域均屈服，其他部分则保持弹性状态。
