【作者】 徐洋；

【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， 2018， 硕士

【摘要】 国家经济的高速发展带动了建设工程项目的不断增多,大型起重机因其巨大的提升能力,满足了以核电、风电以及城镇化建设等大型项目的需求,近些年受到了建设施工方的青睐。以大型塔式起重机、履带式起重机以及全地面起重机为代表的复杂空间组合臂架结构的运用更加广泛,但是随之而来的是在结构稳定性设计分析方面的难题。以往的起重机械结构稳定计算,大多局限于构件层面,设计技术人员往往只针对单一臂架结构及其单肢进行稳定性校核,而忽略了整个组合臂架系统的结构整体稳定性分析,为起重机械的后续使用埋下了极大的隐患。而且对起重机为代表的大型复杂梁杆系统计算分析,往往依赖于大型有限元分析软件,不仅受硬、软件条件的限制,还产生不菲的经济与时间成本,延误新产品研发进程。本文着重就目前常见到多种大柔度空间组合臂架结构的整体稳定问题进行深入研究,从解析计算的角度,为起重机械行业设计人员提供一种快速分析复杂组合臂架稳定性问题的一种计算分析方法和思路。首先分析了工程问题中常见的多节悬臂梁式倾斜折臂式结构。从二阶理论出发,建立非线性四阶微分方程,引入变形协调条件及边界条件,得到折臂式结构平面内稳定性计算公式,同时基于等效长度法以及等效惯性矩法,提出一种折臂式梁等效为变截面竖直悬臂梁形式的等效思路,以便直接借助起重机设计规范关于阶梯柱的稳定验算式,对多节折臂式结构进行稳定性校核。针对单主臂履带起重机、固定副臂履带起重机以及带变幅副臂的履带起重机三种不同臂架组合形式的大型履带式起重机臂架,进行臂架结构整体平面外稳定性分析。综合考虑拉索的非保向力作用对臂架结构受力以及稳定性的影响,基于小位移二阶理论,列写所有臂节非线性二阶微分方程,引入边界条件及变形协调条件,求解获得各自臂架组合形式的平面外失稳特征方程的判据。通过ANSYS的计算仿真,验证理论解正确性。研究腰绳装置臂架稳定的影响,对上述三种带腰绳装置的履带吊大柔度空间组合臂架结构进行几何非线性变形微分方程的列写和求解,推到各自臂架结构的平面外失稳特征判据。研究超起装置以及腰绳装置参数对于各类大型起重运输机械的大柔度空间组合臂架的整体平面外稳定性的影响,根据本文相关理论及有限元方法,分析各个参数对整体结构稳定性的影响效果及程度。本文的研究对象涵盖了目前常见的俯仰变幅式臂架起重机的起重臂结构形式,从解析计算的角度,给出了包括具有主副臂结构的履带式起重机臂架系统在内的大部分俯仰变幅式臂架整体稳定计算分析方法。有别于起重机设计规范中侧重单个构件稳定性的角度,本文研究侧重是设计规范所不涉及的组合结构整体稳定或系统稳定问题。本文的工作某种程度上弥补了起重机设计规范所照顾不到的特定类型起重机臂架整体稳定性分析的难题,为相关起重机设计、生产企业和部门提供了有力的帮助,也为起重机相关规范的进一步修订与完善提供了技术储备。更多还原

【Abstract】 The rapid development of the national economy has led to an ever-increasing number of construction projects.Cranes have met the needs of large projects such as nuclear power,wind power,and urbanization due to their enormous upgrading capabilities.They have been favored by construction and construction parties in recent years.The use of a large tower crane,crawler cranes,and all-terrain cranes for the use of complex spacecombined boom structures has become more widespread,but the consequent difficulties in design analysis of structural stability appear.In the past,the stability calculation of the crane structure was mostly limited to the component level.The design and technical personnel only conducted a single-arm structure and single-limb stability check,neglecting the overall structural stability analysis of the entire combined boom system.For the subsequent use of lifting machinery has laid great hidden dangers.Moreover,the calculation and analysis of large complex beam systems represented by cranes often rely on finite element analysis software,which is not only limited by hard and software conditions,but also generates expensive economic and time costs,delaying the development of new products.This paper focuses on the study of the overall stability of a variety of large flexibility space combined boom structures.From the angle of analytical calculation,it provides a method and idea for the design personnel of the crane industry to analyze the stability of the complex combined boom quickly.In this paper,firstly,the polyline beam structure is introduced.Based on the secondorder theory,with effective deformation coordination conditions and boundary conditions,the in-plane stability calculation method and formula are proposed using the fourth-order differential equation calculation method.At the same time,based on the equivalent length method and the equivalent moment of inertia method,an equivalent idea that the polyline beam structure is equivalent to the multi-segment vertical cantilever beam is proposed.It is convenient to use the conclusion of the design specification of tower crane to check the in-plane stability of polyline beam structure.In this paper,the overall out-of-plane stability of jib structures are calculated for three different large crawler cranes respectively are single-main boom crawler crane,fixed auxiliary-arm crawler crane and tower jib crawler crane.Considering the influence of the non-conservative force of the cable on the force and stability of the jib structure,a reasonable force analysis is performed on the structure.Using the second-order nonlinear theory of small displacements and reasonable boundary conditions and deformation coordination conditions,several second-order differential equations are written for each jib.The buckling characteristic equation for the overall out-of-plane stability of different jib structures is obtained.The results are verified and compared with the finite element method.Considering the influence of the auxiliary bracing device,the deformation differential equations of the three kinds of space jib structure of the caterpillar crane are written and solved,and the buckling characteristic equation for the overall out-of-plane stability of different jib structures is obtained.The influence of the parameters of the super-lifting device and the auxiliary bracing device on the overall out-of-plane stability of various types of the large-flexibility space jib structures are studied,and the effect of each parameter on the overall structural stability were analyzed.The physical model and the equivalent model of a certain crawler crane are compared and analyzed,and the theoretical formula of this paper is used to verify the correctness of the conclusion.The research object of this paper covers the boom structure of the current boom-type luffing jib crane.From the perspective of analytical calculation,most of the crane boom systems including the main and sub-arm structures are included.The method of stability analysis of pitch luffing jib.Different from the angle of emphasis on the stability of individual components in the crane design specification,this study focuses on the overall stability or system stability of the composite structure that is not involved in the design rules.This work to some extent makes up for the difficulty of the overall stability analysis of the specific type of crane boom that is not taken care of by crane design specifications,and provides powerful help for the relevant crane design,production companies and departments,and also for crane-related specifications.Further revisions and improvements provide technical reserves.更多还原