【作者】 孟丽霞；

【导师】 陆念力；

【作者基本信息】 哈尔滨工业大学 ， 机械设计及理论， 2008， 硕士

【摘要】 随着工程建设发展的需要,起重机日益向着大型、高耸、轻柔化、格构式方向发展。由于高强度钢材的大量采用,提高了结构强度,却使刚度和稳定性问题日显突出。复杂桁架式结构的稳定性分析已成为当代大型起重机结构设计计算的难点。具有变截面臂架的格构式起重机之整体稳定性分析更是目前我国起重机设计分析人员所面临的难题。因此,结合起重机设计规范,寻求一种简单、实用、有效的方法极为必要。通过对类似塔式起重机变截面臂架的悬臂格构式结构进行受力分析,引入了这类变截面悬臂结构端部侧向位移的便捷算式。在此基础上,通过位移比较的方法,得出了变截面双肢格构式构件等效为等截面实腹式构件时等效惯性矩的计算公式。并进一步延伸到四肢格构式构件等效惯性矩的计算,给出了变截面四肢格构式构件等效为等截面实腹式构件时,等效惯性矩的计算公式。用有限单元法对不同腹杆布置形式下的变截面构件进行了稳定性分析,对等效惯性矩的计算公式进行了验证。在不改变构件长度的情况下,实现了变截面格构式结构到等截面实腹式结构的等效。对具有变截面臂架的起重机格构式臂架整体稳定性进行了研究,利用上述等效原则将具有变截面结构的臂架等效为实腹式阶梯柱,采用精确有限元理论,列写出多级阶梯柱的组装精确刚度矩阵,由此给出了求解具有变截面结构臂架的失稳临界载荷的计算方法。将本文所研究的等效方法应用于具有变截面臂架的格构式起重机的整体稳定性及结构变形的验算。借助通用有限元程序对FZQ1650动臂式塔机的实际全结构模型及等效模型进行了分析,算例表明,等效惯性矩法有足够的计算分析精度,可供工程设计应用。更多还原

【Abstract】 With the demand of the engineering construction development, the development of crane is increasingly prone to large-sized, dominant-mountain and lattice. By the great deal use of the high-strength steel material, the structure strength is raised, but the problem of structural stiffness and structural stability is made to show to project. The stability analysis of complicated lattice structure becomes the crux of contemporary and large crane structure design and its calculation. The overall stability analysis of the crane’s lattice jib with main and vice-jib structure is even more difficult to technician in our country. So it’s very necessary to seek a simple, utility and effective method to solve the difficulty.By means of internal force analyses to the cantilever lattice structure such as the tower crane which with variable cross-section boom, a simple lateral movement formula is introduced. On the basis of this, the contrast of the algorithm is used in cantilever lattice structure and cantilever solid web beam, we can get the algorithm that can be used to calculate the equivalent inertia moment of the lattice structure when it is regarded as solid web beam.The application of finite element method in the stability analysis is studied by calculate the lattice structure’s equivalent inertia moment in the different arrangements of web member, by this way to test the accuracy of the formula. The initial moment method is improved. So we can realize the equivalent between lattice structure and solid web beam without change its geometry dimension.The overall stability of crane’s lattice boom with variable cross-section structure is studied. Use the related equivalent principle, turn the variable cross-section boom to the solid ladder cylinder. The accurate finite element theory is studied to give the fabricated stiffness matrix, by use of this, the calculation of Euler’s critical stress which with variable cross-section boom is given. The equivalent method is applied to test the crane’s overall stability and structural deformation. To analysis the boom-tower crane FZQ1650’s model between the actual structure and the equivalent structure with the finite element procedure, the result show that the studied equivalent method has enough accuracy, it can be used in actual project.更多还原