大型结构试验模态分析方法研究与软件开发

【作者】 蔡庆喜；

【导师】 马孝江；

【作者基本信息】 大连理工大学 ， 机械设计及理论， 2004， 硕士

【摘要】 机械产品正在向高速高精度轻量化方向发展，振动和噪声问题日益突出。如何提高系统的性能越来越受到人们的重视。对产品进行动力学研究是提高产品性能的主要手段，在产品设计中起着非常重要的作用。其中，试验模态分析是一种有效的方法，在解决工程问题中起着重要的作用，它通过试验的方法来提取系统的模态参数，为系统的结构修改提供依据。 本文对模态分析基本原理进行了深入研究，比较目前广泛使用的几种模态参数识别方法，通过对大型结构试验模态分析特点的分析，提出了一种适用于大型结构试验模态分析整体曲线拟合的改进方法。同时，在Visual C++环境下，采用Matlab数学库工具，设计和开发了此方法的算法程序，完成了试验模态分析的核心步骤——模态参数识别的软件实现，从而为试验模态分析软件系统的开发提供了可行的依据。 在对试验模态分析基本原理深入研究，以及对相应软件的国内外研究开发现状分析的基础上，结合运用OpenGL技术以及Matlab工具，以Windows为系统平台，采用面向对象的Visual C++编程语言，完成了试验模态分析软件系统的研究与开发。 在具体的实际应用中，本系统能够根据结构的一般情况，通过测量激励与响应，得到频响函数，利用整体曲线拟合方法识别出结构的各阶固有频率、阻尼比以及模态振型等模态参数，为以后的动态优化设计提供可靠的依据。同时，利用OpenGL技术实现了结构简单的三维模型绘制，通过三维动画技术将结构的模态振型显示出来，向人们更直观的展示结构的薄弱环节。 最后，通过对一结构进行试验模态分析的实例，给出了应用本系统的过程与方法。在模态试验过程中总结了试验模态分析的注意事项，为正确的进行试验模态分析奠定了基础。实例的分析结果与B&K公司模态分析软件的分析结果基本吻合，表明本软件系统可以用于大型结构试验模态分析，结果正确，能够为动态优化设计提供可靠的依据。更多还原

【Abstract】 The development trend of mechanical products is high-speed, high-precision and portability, which makes the problem of vibration and noise more and more severe. So the technique of improving system performance attracts more attention. One of the main means to improve the performance of products is dynamics study, which plays a quite important role in product designing. Experimental modal analysis is such a method which provides a base for amending system structure by extracting system modal parameters from experiment.On the basis of the theories of modal analysis as well as analyzing the character of experimental modal analysis on large structure, a new global curve fitting method is proposed through the comparison of some identifying modal parameter methods, which applied the experimental modal analysis on large structure. In the integrative development environment of Visual C++, choosing the Matlab tools of mathematics, the arithmetic program is designed anddeveloped, and the software of kernel step on experimental modal analysis-identifyingmodal parameter is completed, which supply the feasible basis for the development of analysis software system of experimental modal.Based on lucubrating the basic theories of experimental modal analysis and analyzing the current research on corresponding software both at home and abroad, a experimental modal analysis software system is studied and developed with OpenGL technology and the tools of Matlab founding on the system platform of Windows.According to the general status of structure, through the measure of force and response, the frequency response function is acquired in practical application. The modal parameters of modal frequency, damp, mode shape and so on are identified with the global curve fitting method, which supply the credible causes for following dynamic optimized design. At the same time, drawing simply the three-dimensional model of structure is completed by using OpenGL technology, which shows the weak points of structure to us through the display of structural mode shape using three-dimensional animated technology.At last, the process and method applying the system is proposed and the notices of experimental modal analysis is summarized by a practical case of experimental modal analysis on a structure. The result is coincided with the modal analysis software of B&K company, which indicates that the software system can be used in experimental modal analysis on large structure and the result is correct, which proves it supplies the credible causes for dynamic optimized design.更多还原