塔式起重机螺栓联接松动影响因素研究

发布时间：2018-03-13 09:16

本文选题：Yamamoto解析法　切入点：有限元接触模型　出处：《山东建筑大学》2017年硕士论文　论文类型：学位论文

【摘要】：由于塔式起重机在工作幅度、起升高度、效率等方面具有显著优势,因此广泛应用于建筑工程,其安全性问题不容忽视。螺纹连接在机械工业生产中应用广泛,可作为一种可拆卸的固定连接,结构简单,拆卸方便,是塔式起重机的塔身标准节采用的主要连接方式之一。在实际工程应用中有多种因素会影响螺纹连接的稳定性,例如螺纹牙的选择、螺距的选取、载荷的方向、载荷的幅值等等。螺栓联接的主要失效形式就是自松弛,其导致螺纹副部分的应力减小,出现相对滑移的现象,降低塔机结构的刚度,影响塔机使用过程中的安全性,严重者会造成塔机标准节的折断,酿成重大安全事故。本文采用QTZ5510塔式起重机标准节螺栓联接作为研究对象,通过建立有限元接触模型模拟横向载荷和轴向载荷工况下螺栓联接的松动过程,来了解不同的因素对螺栓联接松动的影响。1)对于螺栓联接螺纹副的承载力分布的Yamamoto解析法和Junker松动模型进行研究,分析螺纹牙的受力并与松动模型做了对比,用该解析法求出预紧力作用下螺栓联接螺纹处承载力分布的解析解。2)采用Pro\E、Hypermesh、Abaqus三种软件联合建模的方式,建立螺栓联接的三维有限元接触模型。先在Pro\E中建立带有螺旋升角的螺栓联接三维有限元模型,再利用Hypermesh进行六面体网格划分以及相关前处理的设置,最后导入Abaqus中完成边界条件的设置,载荷步的设置以及预紧力的施加。采用直接施加预紧力的方法进行了静态分析,得出螺纹副承载力分布的模拟解。将解析解和模拟解导入Matlab中做成拟合曲线,通过对比采用解析法和模拟法求得的承载力分布曲线,验证了预紧力施加方法的有效性以及有限元接触模型的正确性。3)对模型进行横向动态载荷作用下的动态有限元分析,针对该型塔机选取振动频率以及振幅等数据,研究了夹紧件的振动频率、横向位移幅值、螺纹副摩擦系数、承压面摩擦系数以及不同的螺距对螺栓联接松动的影响。4)对模型进行轴向动态载荷作用下的动态有限元分析,振动频率以及振幅等数据和模型受到横向动态载荷时保持一致,再次研究了夹紧件的振动频率、横向位移幅值、螺纹副摩擦系数、承压面摩擦系数以及不同的螺距对螺栓联接松动的影响。本文的研究明确了哪些因素的影响较大,有利于规避不利因素的影响,便于选取合适的螺栓联接件来提高塔机使用时的安全性,可以有效防止塔机标准节的螺栓联接出现自松弛的现象。对于确保塔机安全,避免重大事故的发生,降低事故风险,具有重要的应用价值和实际意义。
[Abstract]:Because tower crane has remarkable advantages in working range, lifting height, efficiency and so on, it is widely used in construction engineering, and its safety problem can not be ignored. Thread connection is widely used in mechanical industry. It can be used as a detachable fixed connection with simple structure and convenient disassembly. It is one of the main connection methods used in tower body standard section of tower crane. There are many factors that will affect the stability of thread connection in practical engineering application. For example, the selection of thread teeth, the selection of pitch, the direction of load, the amplitude of load, etc. The main failure form of bolt connection is self-relaxation, which causes the stress of the thread pair to decrease and the phenomenon of relative slip. Reducing the stiffness of tower crane structure, affecting the safety of tower crane in the process of use, the severe tower crane standard section will be broken, resulting in a major safety accident. This paper adopts QTZ5510 tower crane standard joint bolt connection as the research object. A finite element contact model was established to simulate the loosening process of bolt connection under transverse load and axial load. To understand the influence of different factors on bolt joint loosening. 1) the Yamamoto analytical method and Junker loosening model for the distribution of bearing capacity of bolt joint thread pair are studied, and the stress of thread tooth is analyzed and compared with the loosening model. The analytical method is used to calculate the analytical solution of the bearing capacity distribution at the thread of bolt connection under pretightening force. (2) the combined modeling method of Pro\ Hypermesh Abaqus software is used. The 3D finite element contact model of bolt connection was established in Pro\ E, and then the hexahedron mesh was divided by Hypermesh and the relevant pre-processing was set up. Finally, the boundary condition, load step and pretension force are set up in Abaqus, and the static analysis is carried out by the method of directly applying preload force. The analytical solution and the simulated solution are introduced into Matlab to form fitting curve. The distribution curve of bearing capacity is obtained by comparing the analytic method and the simulation method. The validity of the pretightening force application method and the correctness of the finite element contact model. 3) the dynamic finite element analysis of the model under transverse dynamic load is verified. The vibration frequency and amplitude of the tower crane are selected. The vibration frequency, the amplitude of transverse displacement, the friction coefficient of thread pair, the friction coefficient of bearing surface and the influence of different pitch on the loosening of bolt connection are studied. 4) the dynamic finite element analysis of the model under axial dynamic load is carried out. The data and model of vibration frequency and amplitude are consistent when subjected to transverse dynamic load. The vibration frequency, transverse displacement amplitude and friction coefficient of thread pair are studied again. The influence of friction coefficient of bearing surface and different pitch on loosening of bolt joint. The research in this paper has made clear which factors have great influence, which is helpful to avoid the influence of unfavorable factors. It is convenient to select suitable bolt connectors to improve the safety of tower cranes in use, and can effectively prevent the self-relaxation of bolt connections in tower cranes' standard section. To ensure the safety of tower cranes, to avoid the occurrence of serious accidents and to reduce the risk of accidents, It has important application value and practical significance.
【学位授予单位】：山东建筑大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH213.3

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