【作者】 赵俊杰；

【导师】 田红旗；

【作者基本信息】 中南大学 ， 交通运输工程， 2013， 博士

【摘要】 起重机是物料搬运行业主要的运输工具,其间歇、重复、循环的工作特点会引起短时、强激励、交变的运行状态,需重点研究其在垂直和扭转方向产生的冲击和振动等动载效应。本文密切结合起重运输机械行业的工程实际需求,提出了多自由度提升系统动力学模型和多段集中质量主梁扭振动力学模型,通过自适应步长四阶Runge-Kutta法进行数值求解,结合现场试验对提升系统和主梁扭振动力学进行了研究及优化分析,研究成果可以为起重机详细设计提供理论依据。主要研究内容与创新点如下：(1)构建了增加自由度的提升系统动力学模型,新增自由度包括：提升钢丝绳时变刚度、减速机构扭转自由度、吊钩以及端梁垂向自由度。基于所建立的系统动力学模型,开发了Simulink求解程序,采用自适应步长四阶Runge-Kutta法高效求解,结果与试验测得的结果吻合,验证了模型的合理性。研究了各种典型工况下提升系统的动力学特性,获取了关键部件在对应工况下的动载系数,为起重机关键零部件设计载荷的选取提供了参考。首次研究了在提升速度一定的情况下,影响提升动载系数的其它因素,为保持起重机运行效率不降低的前提下,进一步减小提升动载系数提供了理论依据。(2)提出了多段集中质量主梁扭振模型,将主梁扭振问题转化为类传动轴系扭振问题,采用Simulink进行了数值求解,结合现场试验,验证了扭振模型的合理性。研究了吊重离地起升及突然减载工况下的扭振振型和衰减规律,分析了主梁截面、小车对重、吊钩偏心量及小车在主梁上的位置等因素对扭振的影响规律,得到了影响主梁扭振的主要因素,比较了标准工字梁和焊接箱梁扭振特性的差异,为主梁设计时考虑扭振动载及解决主梁因扭振引起的材料失效问题奠定了基础。(3)建立了综合考虑提升动载和主梁扭转动载等特性的主梁自重多目标优化模型,解决了以往主梁优化仅考虑自重而引起其它部件设计载荷过大的问题。采用本文建立的提升系统和主梁扭振求解模型,以5吨单梁起重机为研究对象,针对吊重离地起升工况进行了全程多目标优化。研究了不同种群规模和进化代数对优化结果的影响,得到了适合于起重机多目标优化的种群规模和进化代数；对计算得到的Pareto非劣解进行了研究分析,结果比单目标优化更为丰富,研究成果已应用在新型主梁设计中；选取不同动态特性参数作为优化目标,研究了多目标优化模型如何选取合理的优化目标。更多还原

【Abstract】 Crane is one of the major transportation tools in material handling industry; it features intermittent, repeating, and circular working characteristics. During working, cranes may frequently start and brake. It need to focus on research in dynamic effects of the impact and vibration in the vertical direction and the reverse direction.Based on the new development projects of crane lifting mechanism and the main beam from the famous German company M2, it proposed the multi-degree freedom lifting system dynamics model and centralized multi-segment quality girder torsional vibration dynamics model. The solution was worked out though the fourth-order adaptive step Runge-Kutta method, and research and optimization analysis of the test on site to lifting system dynamics model and main beam torsional vibration dynamics model.The research results can provide a theoretical basis for the detailed design of the crane key components. Main contents and innovations are as follows:(1) This article established serial lifting system dynamic theoretical models which increased the degree of freedom. The increased degree of freedom included:time-varying stiffness of hoisting rope, the rotational freedom degree of deceleration mechanism, the vertical freedom degree of hook a beam end. Based on the established system dynamics model, it used Simulink tools to build a solving procedures of theoretical model, and took adaptive step size fourth-order Runge-Kutta method to solve. The solving results were compared with the experimental results. The results validate the model is reasonable. Based on the validated model, the dynamic characteristics of lifting system has been researched under different working condition. It worked out dynamic load coefficient reference value of key components under different working condition, and provide important reference to the input load choice of crane key components design. In addition, it researched other factors that influence the lifting dynamics load coefficient under the fixed lifting speed. Under the premise of the not reduced crane operating efficiency, it provided the theoretical basis for reducing vertical lifting dynamic load.(2) It proposed main beam torsion vibration model of multi-segment and three-segment concentrated mass so that the issue of main beam torsion vibration was changed to similar torsion vibration issue of transmission axles. By the Simulink program, the solving model of main beam torsion vibration was established. It validated the test on the test bench built specially and validated the rationality of torsion vibration. Based on the validated torsion vibration, it studied the distribution and attenuation regulation of torsional vibration under the working condition of hoist lifting off the ground and suddenly load shedding, and analyzed the regulation of torsion vibration caused by main beam section, the car counterweight, hook eccentricity and location of the car in the main beam and other factors. It carried out the main factors which can influent main beam torsion vibration. After comparing the torsion vibration characteristics between with beams and welded box girder, it provided the basis for considering torsion vibration dynamics load in the main beam design process and for the failure of the material caused by torsion vibration of the main beam.(3) Multi-objective genetic algorithm optimization model was established by a comprehensive consideration of vertical lift and the main beam torsional dynamic load etc. characteristics. It avoided the design load of other components was too large because the weight of beam was considered only during the the beam optimization. the optimization model used the established lifting system simulation model and the main beam torsional vibration simulation model.Regard5ton single beam crane as the research object, it did the multi-objective optimization according to the working condition of lifting off the ground. The paper did the research for the influence of selected different population size and evolution algebra on optimization results and analyzed the calculated Pareto optimal. By selecting a different amount of dynamic parameters as optimization objective, it studied the reasonable values of selecting optimization model amount in main beam multi-objective optimization model.更多还原