开孔梁的疲劳损伤度研究

RESEARCH ON THE FATIGUE DAMAGE DEGREE OF A BEAM

船舶结构中,在强桁材腹板上开孔常会引起应力集中问题。基于此,对强桁材上开孔边界结构的疲劳强度进行了评估,针对开孔位置的变化引起的孔边疲劳强度的变化进行仿真模拟,建立了两者间相互关联的力学模型,并利用1stOPT软件,对不同开孔位置下,孔边结构疲劳损伤度的变化进行了无因次的参数拟合,在定性分析的基础上,提出开孔位置距离纵桁端部的有效距离达到跨长的1/6时,孔边结构的疲劳强度问题将成为结构破坏的主要失效模式,因而在实际工程的设计和制造中,当开孔位置过于靠近纵桁端部时,应该以结构的疲劳强度响应作为安全校核的基础之一。

In the ship structures,when a hole is made on the beam,the stress distribution of the beam will not be uniform,but concentrated.On the basis of this special stress state,it is made a numerical simulation to analyze the fatigue strength of the local high-stress structures.Basd on the qualitative research about the change of the structural fatigue strength with the move of the hole position.and using the software of 1stOPT,the structural fatigue damage degree is expressed by a fitting formula,which established rule of the transmission of hole position and the change of the structural fatigue strength.which shows that at the distance of 1 /6 valid span of the beam,the major failure mode of the structure is attributed to the lack of the fatigue strength.the result shows that the hole should only be placed far away from the end of the beam by 1 /6 valid span of the beam,and the structural fatigue strength should be regarded as one of the main foundational factors to check the safety of the whole structure system.