波浪荷载作用下船闸人字门结构疲劳分析

发布时间：2018-04-24 13:42

本文选题：人字闸门 + 有限元法　；参考：《重庆交通大学》2014年硕士论文

【摘要】：船闸人字闸门因其结构形式布置合理、运行方便可靠、闸门启闭力小以及节省材料等优点,已经成为大中型船闸的主要工作门型。在实际运行过程中,船闸人字门存在疲劳开裂问题。国内外学者对大型船闸人字门开展有限元研究分析和水弹性材料的模型试验,主要是基于人字闸门的结构内力计算,鲜有涉及人字门运行后的疲劳开裂研究。因此,在采用适当的分析方法对船闸人字闸门进行结构内力计算的基础上,进一步展开对结构疲劳的研究,并提出合理的抗疲劳措施,具有较重要的理论及实际意义。本文利用ANSYS有限元软件建立人字闸门三维空间结构有限元模型,针对依托工程选取不同工况进行有限元分析计算,并基于结构疲劳理论,首次引入FE-SAFE疲劳计算软件对人字闸门进行疲劳寿命分析,主要结论如下： 1、设计工况下,人字闸门的整体结构朝下游侧凸出,结构变形和应力呈现对称分布趋势,整体最大折算应力与最大变形均位于面板中下部。面板结构起到挡水和传递荷载的重要作用,在局部位置如面板与主梁连接处存在应力集中现象。主梁结构为主要受力构件,其最大折算应力出现在主梁端部,最大变形出现在主梁结构跨中处,腹板处应力值远大于上下翼缘,易发生翘曲变形。 2、高水工况下,闸室内外水位较高,静水荷载作用于闸门的范围更广,闸门整体最大折算应力与最大变形均位于面板中上部。由于人字闸门主横梁按等荷载布置,上部主梁间距更大,导致上部结构的内力及变形也随之增大。两种工况下结构整体最大变形相差54.41%～68.69%,整体折算应力相差55.65%～64.08%,二者应力和变形的变化趋势相差甚大。 3、波浪荷载作用下闸门的疲劳分析结果表明,疲劳破坏主要出现在面板与主横梁连接处与主横梁端部。波高值从0.1增大到1.5m时,人字闸门疲劳对数寿命值相差42.3%。波高值线性递增时,人字闸门疲劳循环次数按指数级递减。 4、其他影响因素分析表明,残余拉应力导致人字闸门疲劳强度降低,残余压应力存在时结果反之；材料表面参数与闸门疲劳寿命成反比,表面参数小于1.5时,结构疲劳寿命递减速度快,而这之后递减趋势变缓。 5、在人字闸门设计时,可从结构选材、局部设计、残余应力控制、降低应力幅值以及减小材料表面参数等五个方面提高结构抗疲劳强度。
[Abstract]:The herringbone lock gate of ship lock has become the main working door type of large and medium ship lock because of its advantages such as reasonable arrangement of structure, convenient and reliable operation, small opening and closing force of gate and saving material. In the process of practical operation, the problem of fatigue cracking exists in herringbone gate of ship lock. The finite element analysis and hydroelastic material model test of large herringbone gate are carried out by scholars at home and abroad, mainly based on the calculation of structural internal force of herringbone gate, few of which are related to fatigue cracking of herringbone gate. Therefore, on the basis of the calculation of structural internal force of the herringbone gate of ship lock by appropriate analysis method, the further research on structural fatigue is carried out, and the reasonable anti-fatigue measures are put forward, which is of great theoretical and practical significance. In this paper, the finite element model of the three dimensional structure of the herringbone gate is established by using the ANSYS finite element software, and the finite element analysis and calculation are carried out according to the different working conditions of the engineering, and based on the theory of structural fatigue. The fatigue life of the herringbone gate is analyzed by FE-SAFE fatigue calculation software for the first time. The main conclusions are as follows: 1. Under the design condition, the whole structure of the herringbone gate is projecting downstream, the deformation and stress of the structure show a symmetrical distribution trend, and the whole maximum converted stress and the maximum deformation are all located in the middle and lower parts of the panel. The slab structure plays an important role in retaining water and transferring load, and there is stress concentration phenomenon in the local position such as the connection between the slab and the main beam. The main beam structure is the main force member, its maximum reduced stress appears in the end of the main beam, the maximum deformation occurs in the middle of the span of the main beam structure, the stress value of the web is much larger than the upper and lower flange, and the warping deformation is easy to occur. 2, under high water condition, the water level inside and outside the gate chamber is higher, and the range of static water load acting on the gate is wider. The maximum commutation stress and the maximum deformation of the gate are all located in the upper part of the slab. As the main beam of the herringbone gate is arranged according to the equal load, the distance between the upper main beams is larger, which leads to the increase of the internal force and deformation of the superstructure. The difference between the maximum deformation of the whole structure and that of the whole structure under the two working conditions is 54.41 and 68.699.The difference of the integral converted stress is 55.65 and 64.08, and the variation trend of the stress and deformation is quite different. 3. The fatigue analysis results of the gate under wave load show that the fatigue failure mainly occurs at the junction between the slab and the main beam and at the end of the main beam. When the wave height is increased from 0.1 to 1.5 m, the logarithmic fatigue life of the herringbone gate is 42.3. When the wave height increases linearly, the fatigue cycle times of herringbone gate decrease exponentially. 4. The analysis of other influencing factors shows that the fatigue strength of the herringbone gate decreases due to the residual tensile stress, and the results are reversed when the residual compressive stress exists, and the material surface parameters are inversely proportional to the fatigue life of the gate, and when the surface parameters are less than 1.5, The fatigue life of the structure decreases rapidly, but the decreasing trend slows down after that. 5. In the design of herringbone gate, the fatigue strength of the structure can be improved from five aspects: material selection, local design, residual stress control, reducing stress amplitude and decreasing material surface parameters.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U641.3

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