【作者】 刘世豪；

【导师】 叶文华；

【作者基本信息】 南京航空航天大学 ， 机械电子工程， 2013， 博士

【摘要】 随着我国航空航天、船舶与海洋工程、大型冶金机械、能源设备和汽车等制造业的蓬勃发展，对各种复杂零部件的加工需求日益增加，使龙门机床也迅速得到发展。进给系统作为龙门机床的重要组成部件，其动态性能对机床的加工精度影响较大，是机床设计领域的研究重点和难点。在龙门机床工作过程中，进给系统同时受热与力的作用而产生热—力耦合效应，进而影响到进给系统的变形和振动。已有的研究方法通常是分别针对进给系统的力学性能和热态性能进行分析设计，这使得进给系统动态性能的分析不够全面，也造成进给系统综合性能难以进一步提高。针对以上问题，本论文深入研究龙门机床进给系统的热—力耦合机理，提出基于热—力耦合的动态建模方法、动态分析方法及多目标优化设计方法。结合企业实际的龙门机床进给系统样机进行理论分析和实验对比，验证所提出方法的正确性和有效性。本论文的主要研究工作和成果如下：（1）根据龙门机床进给系统在工作过程中受力和热共同影响的特点，提出一种基于温度场和动力学性能耦合的动态建模方法。在探索龙门机床进给系统的热—力耦合机理的基础上，建立了龙门机床进给系统的热—力耦合动态模型，并采用中心差分法和矩阵迭代法进行模型求解。结合动态实验和理论分析对比，验证了所提出建模方法的正确性。（2）研究龙门机床进给系统的热—力耦合效应对动态性能的影响，提出一种多时间步有限元仿真和温度场实验相结合的热—力耦合动态分析方法。根据所提出的方法，对所研究的龙门机床进给系统进行热—力耦合瞬态和稳态分析后发现：在进给系统达到热稳态之前，随着温度的不断升高，热—力耦合效应使进给系统的振幅变大，导致振动加剧。研究表明，在对龙门机床进给系统进行分析设计时，需要考虑热—力耦合效应对动态性能的影响。（3）为了更加全面地分析龙门机床进给系统的动态性能，提出一种基于热—力耦合的结构参数影响动态性能的分析方法。在龙门机床进给系统达到热－力耦合稳态的情况下，采用所提出的方法研究其各种结构参数的变化对动态性能的影响规律，揭示对动态性能影响较大的结构参数。研究结果表明，拖板的质量和抗振性对龙门机床进给系统的动态性能影响较大。（4）综合考虑龙门机床进给系统工作过程中的热—力耦合效应与动态性能，提出了一种多目标优化设计方法。该方法采用正交试验法和二阶响应面法建立近似优化模型，将改进的粒子群算法和灰色关联分析法作为求解方法。将所提出的方法用于进给系统拖板的多目标优化设计，使拖板的质量减轻，并且第一阶固有频率得到较大提高，结合静动态实验验证了本论文提出的多目标优化设计方法的可行性和正确性。更多还原

【Abstract】 With the booming of China’s aerospace, shipbuilding and marine engineering, large metallurgicalmachinery, energy equipment, automobile industry, etc., the demand of large and complexcomponents is increasing, which contributes to the development of gantry machine tools. As animportant component of gantry machine tool, the dynamic performance of feed system greatlyinfluences the machining accuracy of the gantry machine tool, which has become a research emphasisand difficulty in machine tool design area. The feed system is affected by the thermal-mechanicalcoupling effect from the joint action of heat and force during the working process of gantry machinetool, which leads to deformation and vibration of feed system. Nevertheless, existing methods used inanalyzing and designing of the feed system focus on improving the mechanical performance orthermal performance only, which makes it hard to improve the overall performance of feed system.To solve the above problems, on basis of studying gantry machine tool feed system’sthermal-mechanical coupling mechanism, some new methodologies were proposed in this paper,which are the thermal-mechanical coupling dynamic modeling method, dynamic analysis method andmulti-objective optimization design method for gantry machine tool feed system. The correctness andeffectiveness of the proposed methodologies were verified by comparing the results oftheoretical analysis and experiments on prototype of gantry machine tool’s feed system in a factory.The main research work and achievements are as follows(1) Through considering that the gantry machine tool feed system is affected by joint action ofheat and force during the working process, a dynamic modeling method was proposed, which is basedon the coupling effect of the temperature field and kinetic properties. By exploring thethermal-mechanical coupling mechanism of gantry machine tool feed system, a thermal-mechanicalcoupling dynamic model of the gantry machine tool feed system was established, which was solvedthrough using the central difference method and the matrix iterative method. The correctness of thegantry machine tool feed system’s dynamic modeling method was verified by comparing thetheoretical analysis results with experimental results.(2) Through studying the law of thermal–mechanical coupling effect on gantry machine tool feedsystem’s dynamic performance, and a thermal–mechanical coupling dynamic analysis method wasproposed by combining multi-step finite element simulation with temperature field experiment.According to the method proposed, thermal–mechanical coupling transient and steady-state analysison gantry machine tool feed system were conducted and conclusions obtained are as follows, before the whole feed system reaches thermal balance state, the vibration amplitude of the feed systemincreases with the temperature rising, which leads to the intensifying of vibration. Therefore, in theprocess of gantry machine tool feed system’s analysis and design, the influence ofthermal–mechanical coupling on dynamic performance must be considered.(3) In order to study the dynamic performance of gantry machine tool feed system more fully, aanalysis method of structural parameters affecting the dynamic performance dynamic was proposed,which is based on the thermal-mechanical coupling. During the thermal-mechanical coupling steadystate of gantry machine tool feed system, the above proposed method was introduced to study theimpact law of the various structural parameters on its dynamic performance, and identify thestructural parameters that have great influence on the dynamic performance. The study results showthat the carriage’s mass and anti-vibration performance has great influence on the dynamicperformance of gantry machine tool feed system.(4) A multi-objective optimization design method was proposed through considering the gantrymachine tool feed system’s thermal–mechanical coupling effect and dynamic performance. Themethod uses the orthogonal experimental method and the second-order response surface method toestablish the approximate optimization model. An improved particle swarm algorithm and greyrelational analysis method are taken as the solving method. After using the proposed method toconduct multi-objective optimization design for the feed system’s carriage, the carriage’s massdecreases, thermal–mechanical coupling performance is improved, and the first order naturalfrequencies increase greatly. Finally, the correctness of multi-objective optimization design methodproposed in this paper was verified by the static and dynamic experiments.更多还原