共查询到20条相似文献,搜索用时 203 毫秒
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针对大型真空炉炉门组件建模困难,计算资源消耗大等问题,采用混合建模方法进行了有限元模型简化,基于多点约束(MPC)法建立真空炉炉门体-壳组合模型,并与全实体模型计算结果及实验测试值进行对比分析。结果表明,采用体-壳单元混合建模在真空炉炉门应力分布规律求解上与实体模型结果及实验测试值基本一致,有着较高的计算精度,可为大型复杂真空炉设备仿真分析等工程问题提供可行的参考方案。 相似文献
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龙门架钢结构有限元分析及其技术处理 总被引:5,自引:1,他引:4
利用大型通用有限元分析软件ANSYS对龙门架钢结构进行强度分析。利用梁单元和实体单元各自的优点,通过二次建模互补进行结构有限元分析。利用梁单元快速发现大型龙门架结构中的薄弱环节;利用实体单元进一步得到危险部位的更准确解,以达到最佳的分析效果。 相似文献
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对结构和受载都非常复杂的某大型组合管式反应塔建立了有限元模型。采用壳单元对组合管式反应塔进行网格划分,既降低了建模难度,又减少了有限元模型的节点数,提高了计算速度。分析了组合管式反应塔所承受的各种载荷。采用Lanczos算法对组合管式反应塔进行模态分析,得到其固有频率,从而可以计算反应塔对风栽荷和地震载荷的动态响应。 相似文献
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多约束状态下重载机械式主轴有限元建模及模态分析 总被引:16,自引:0,他引:16
重载机械式主轴是重型数控(Computer numerical control,CNC)机床摆角铣头的关键功能部件,具有大功率、大扭矩特点,用于加工大型复杂曲面零件。其有限元建模及模态分析的准确性是主轴进一步动力学分析的基础。基于Timoshenko梁理论建立重载机械式主轴的运动方程,采用有限元法得到主轴的矩阵形式的动力学方程;在有限元软件中分别以实体单元和梁单元对主轴进行有限元建模,对轴承以Combin14弹簧单元建模,并以自由模态和实际工况约束条件下进行重载机械式主轴的模态分析;根据轴承型号计算轴承的径向刚度,作为重载主轴模态分析中弹簧单元的刚度参数;进行主轴锤击模态试验,验证重载机械式主轴多约束状态下模态分析建模及仿真结果的正确性。研究表明,把主轴考虑为Timoshenko梁单元和Beam188梁单元进行主轴有限元建模和模态分析时,结果更为准确,弹簧约束梁方式更符合实际情况。研究结果为重载机械主轴系统的进一步优化设计和精度控制提供依据。 相似文献
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基于有限元技术的塔式起重机建模分析 总被引:3,自引:0,他引:3
基于有限元技术,利用有限元分析软件ANSYS对某塔式起重机进行有限元建模分析,对建模中的结构简化、单元选择、边界条件处理等进行了探讨和分析.并在此基础上对塔式起重机进行有限元求解分析,将分析结果与该塔机现场试验结果进行比较,验证了模型的可行性. 相似文献
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有限元法已广泛应用于结构的应变,应力及动力学分析,而利用有限元进行刚体机构的运动分析的研究较少.基于最小势能原理,推导出一种新型两端铰接间有限元连杆单元的梯度矢量、刚度矩阵和Hessian矩阵.并对关节轴线平行和共面这两种特殊几何关系下的单元模犁进行研究,给出计算公式和方法.在大型可展机构中,大量存在着结构相同的重复机构和闭环运动链.而基于有限元的运动学方法可以在不进行运动链分解的前提下,实现空间闭环机构的运动学分析.利用该方法对三种典型的空间闭环机构进行运动学仿真.其计算结果表明,应用该单元对空间闭环机构进行运动学分析,建模简单,计算正确,在大型可展机构中有很好的应用前景. 相似文献
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Hookyung Lee Sangmin Choi Minsu Paek 《Journal of Mechanical Science and Technology》2010,24(7):1515-1521
The purpose of this study is to recognize modeling methods for coal combustion and gasification in commercial process analysis
codes. Many users have appreciated the reliability of commercial process analysis simulation codes; however, it is necessary
to understand the physical meaning and limitations of the modeling results. Modeling of coal gasification phenomena has been
embodied in commercial process analysis simulators such as Aspen. Commercial code deals with modeling of the gasification
system with a number of reactor blocks supported by the specific code, not as a coal gasifier. However, the primary purpose
of using process analysis simulation code is to interpret the whole plant cycle rather than an individual unit such as a gasifier.
Equilibrium models of a coal gasifier are generally adopted in the commercial codes, where the method of Gibbs free energy
minimization of chemical species is applied at the given temperature and pressure. The equilibrium model of the coal gasifier,
RGibbs, in commercial codes provides users with helpful information, such as exit syngas temperature, composition, flow rate,
performance of coal gasifier model, etc. with various input and operating conditions. This simulation code is being used to
generate simple and fast response of results. Limitations and uncertainties are interpreted in the view of the gasification
process, chemical reaction, char reactivity, and reactor geometry. In addition, case studies are introduced with examples.
Finally, a way to improve the coal gasifier model is indicated, and a kinetically modified model considering reaction rate
is proposed. 相似文献
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通过回顾机床主轴发展历程,指出电主轴在高端数控机床的应用日益广泛。继而详尽地阐述了机床主轴单元的设计要点,包括轴承、润滑和冷却以及刀具接口等。接着对主轴的静动态和热性能分析以及建模仿真进行了全面介绍。最后指出主轴的工况监控、智能化和自适应控制是新一代电主轴的重要特征和未来发展趋势。 相似文献
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三维几何模型是齿轮有限元分析及齿轮机构虚拟仿真的基础,通常的CAD系统要通过编程才能实现齿轮三维模型的构建.为此提出一种基于开放性图形库(OpenGL)的齿轮三维模型直接构建方法.该方法定义了构建齿轮的基本单位即齿元,并利用图元构造齿轮齿元.通过对齿轮齿元进行顶点操作实现阵列功能,以及对齿元进行模型变换实现拉伸功能,来实现整个齿轮的三维模型构建.这一方法可通过指定顶点数量自由控制齿元建模精度,提高整个齿轮几何模型的精确度,较方便地满足齿轮CAE和虚拟仿真的要求. 相似文献
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利用计算机设计选型取代传统高成本、低效率且费时的空调箱选型,以Visual Basic 6.0为编译环境,Auto CAD软件为图形输出平台,Microsoft Office软件为文件输出平台,开发了一款空调箱数字化分析与选型软件,通过自定义项目、自定义机组、设计机组功能段,对表冷器、加热器、热回收、加湿器等重要功能段进行建模,对空调箱进行系统全面的分析选型,并且能够输出Auto CAD图纸及选型机组信息的Excel/Word文件,大大降低空调箱设计成本及开发周期,提高整体设计效率及精度。 相似文献
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Configuration Selection for Reconfigurable Manufacturing Systems by Means of Characteristic State Space 总被引:2,自引:1,他引:1
The configuration selection for reconfigurable manufacturing systems(RMS) have been tackled in a number of studies by using analytical or simulation models. The simulation models are usually based on fewer assumptions than the analytical models and therefore are more wildly used in modeling complex RMS. But in the absence of an efficient gradient analysis method of the objective function, it is time-consuming in solving large-scale problems by using a simulation model coupled with a meta-heuristics algorithm. In this paper, a new approach by means of characteristic state space is presented to improve the efficiency of the configuration selection for an RMS. First, a characteristic state equation is set up to represent the input and the output resources of each basic activity in an RMS. A production process model in terms of matrix equations is established by iterating the equations of basic activities according to the resource flows. This model introduces the production process into a characteristic state space for further analysis. Second, the properties of the characteristic state space are presented. On the basis of these properties, the configuration selection in an RMS is considered as a path-planning problem, and the gradient of the objective function is computed. Modified simulated annealing(SA) is also presented, in which neighborhood generation is guided by the gradient to accelerate convergence and reduce the run time of the optimization procedure. Finally, several case studies on the configuration selection for some actual reconfigurable assembly job-shops are presented and compared to the classical SA. The comparison shows relatively positive results. This study provides a more efficient configuration selection approach by using the gradient of the objective function and presents the relevant theories on which it is based. 相似文献