【作者】 李吉；

【导师】 马孝江；

【作者基本信息】 大连理工大学 ， 机械电子工程， 2002， 博士

【摘要】 旋转机械的发展有着悠久的历史，随着工业的发展，其种类和数量都不断增多。大量的旋转机械在运转时产生强烈的噪声，因而给人们的日常工作和生活带来许多烦恼。为了降低噪声，许多研究人员付出了艰辛的努力，经过几十年的研究和实践，总结出许多降低机械设备噪声的理论和成功的经验，取得了不少有益的研究成果，许多设备设计制造部门也开辟了噪声研究的新领域，研制出不少低噪声机械产品，促进该方向不断发展与完善。 结构噪声是旋转机械的主要噪声源之一，尤其是对于如齿轮箱这类具有封闭壳体的机械和如振动筛这类以振动为主要工作方式的机械，结构振动辐射声能占总声能的比例甚至可以达到90～95％，因此不解决结构噪声问题旋转机械噪声就不能得到有效的控制。这方面的研究虽然很多，但多数研究都是针对某一具体设备、某一部件或某一种方法而进行的，缺乏整体性、系统性和普遍性。根据这种情况，本文以旋转机械结构噪声为主要对象，比较系统地对结构声辐射的性质、声源识别方法、结构声的主要影响因素以及旋转机械结构噪声控制的普遍方法进行了研究，具体研究内容如下： (1)箱形结构声辐射性质的研究。以变速箱为对象，对实际激励条件下箱形结构的声辐射效率进行了试验研究，重点考察了这种结构在实际激励下的声辐射效率同已知的简单结构声辐射效率的异同以及激励的改变对辐射效率的影响。通过试验发现，总体上变速箱辐射效率随频率的变化规律同简单构件的辐射效率是一致的，但在250Hz以下的低频区域，变速箱的辐射效率大大高于任何一个经验公式的计算结果；通过换档试验发现，激励的改变对辐射效率的影响不很显著，工程计算可以不予考虑；对于变速箱这类三个方向尺寸差别不大的结构，其辐射性质具有平板和球源的双重特征，辐射效率介于平板和脉动球源之间，据此提出在工程应用时可以取平板和脉动球源辐射效率的平均作为此类结构辐射效率的观点。 (2)复杂声场中结构声源的层次识别。对复杂声场中结构声源的识别方法进行丁研究，提出了结构声源的层次识别方法，从实用的角度出发，重点对前两个层次的具体识别方法进行了研究。针对有无固定评价点两种情况提出了近场测量修正法、远近场综合模糊识别法，使声源识别的精度明显提高。根据表面速度法在工程应用中存在的问题提出了频带声压级差值法，该方法能快速准确地确定结构声在总噪声中的地位和结构的具体发声部位。 (3)旋转机械结构噪声控制机理的研究。在旋转机械结构噪声控制方面，根据旋转机械的基本特征，建立了旋转机械结构噪声分析的简化模型，基于该模型利用解析与数值计算相结合的方法对结构噪声的各种影响因素进行了分析，通过计算分析发现，转子与机体的连接刚度是机体结构声的最敏感参数，同时各参数对结构噪声的影响具有互补性。基于分析结果提出降低旋转机械结构噪声的普遍有效方法。最后通过模型试验验证了分析结果。 大连理工大学博士学位论文 摘要 （4）通过振动测量结构辐射噪声及其在产品质量评价中的应用。基于结构表面振动速度与结构辐射声能的关系，针对以结构声为主的机械产品的现场噪声评价问题，提出根据结构表面单点振动速度和工作振型来计算结构辐射声能的方法，此法大大加快和简化了机械产品现场噪声检测的过程。通过变速箱实验证明这种方法是可行的。 （5）结构噪声控制技术的应用——惯性振动筛噪声控制。根据本文对于旋转机械结构噪声控制技术的研究结果和惯性振动筛工作的特殊要求，对有关参数的选择进行了讨论，并通过试验为降低惯性振动筛噪声找到了两个新的方法：即，在轴间相对运动要求不高的情况下，可以在激振器（或轴承）与筛体之间安装一组减振器，通过适当选取减振器参数，既可以使机体在工作频率附近获得稳定振幅，保证振动筛正常工作，又可以使机体的高频响应减小，降噪效果显著；反之，如果轴间相对运动精度要求较高，可以采用空心滚动体轴承，在保证滚动体强度的条件下也可以获得较好的降噪效果。尽管这两种方法应用条件有所不同，但基于同一种基本原理。这两种方法虽然只是在振动筛上进行了试验，同样也适用于满足相应条件的其它旋转机械。更多还原

【Abstract】 With the development of industry, the kinds and numbers of rotary machine continuously increase. Lots of rotary machines bring strong noise when they rotate. As the result of the noises, the people feel very annoyance in their daily life. Many researchers have taken much efforts to reduce the noise. With decades years research and experience, we have summarized many theories of reducing equipment noise and successful experience, acquired lots of useful achievements. Many equipment designers and manufacturers broken new fields of noise research, developed numerous low noise mechanical products and impelled this field developing and perfecting continually.The frame radiated noise is one of the major noise resources of rotary machines, especially for gear case which has close shell and vibrating screen which works in vibrating ways, the frame radiated noise energy account for more than 90% of total sound energy. So if we could not successfully resolve the problem, the noise of rotary machines would never be effectively controlled. Although there are much research in the field, most research only deal with special machine, special part in some way. It is short of systematicness and popularity. In view of this case, the paper mainly studied sound radiation properties of structure, sound source identification methods, main factors affecting frame radiated noise and the common way to control the noise radiated by rotary machines. The detail research shows as fellows:(1) Study on sound radiation properties of box-shape structure. Taking gear case as research object, we studied the sound radiant efficiency of complex box-shape structure under practical stimulation by experiment, mainly observed the difference of sound radiant efficiency between the complex structure under practice stimulation and the known simple structure. By experiment, we found that the variation of gear case radiant efficiency with frequency keep accordance with that of simple one as a whole, but the radiant efficiency of gear case will go beyond any calculation result of empirical formula when the frequency is below 250Hz. We also found that stimulation changes affect radiant efficiency little by varying speed experiment, and it can be ignored in engineering calculation. The rectangle structures as gear case, possess characters of both plane and ball, and their sound radiant efficiency lie between plane and ball region. So we propose that the mean of radiant efficiency of plane and pulse ball region can act as that of this kind of structure in practice.(2) Sequential distinguish of structure sound resource in complex sound field. We studied the sound source identification methods in complex sound field andinproposed the sequential sound source identification method. In the practicality point of view, we mainly studied the details of the former two layers. We proposed the means of near field measurement correction and far-near-field fuzzy distinguish synthesis according to if fixed evaluation points exist. The method advanced in precision. We also proposed a reformed surface speed method based on the problems of surface speed method in engineering application. This method can make sure the structure radiant sound status in total noise and the detail phonate part quickly and correctly.(3) Study on the control mechanism of structure noise radiated from rotary machines, we build a common model of rotary machine structure noise analysis relied on the general characters of rotary machines. Based on this model, we analyzed various influence factors to structure radiant noise using the union of revolution and numerical calculation method. We found that the joint stiffness between the rotor and the frame is the most sensitive parameter of structure radiant noise by calculating and analyzing. Moreover, each parameter’s effect is mutual compensatory. We advanced a general valid method to reduce the structure radiant noise of rotary machines based on the analysis results. At last, we tested the analysis results by model experiment.更多还原