【作者】 温华兵；

【导师】 左言言；

【作者基本信息】 江苏大学 ， 车辆工程， 2014， 博士

【摘要】 随着工业的发展,动力机械设备的运行功率增大,振动能量增强,而工程结构日益向轻、薄方向发展,导致结构振动和噪声问题日益严重。在产品设计阶段有效预测产品的声振特性,采取有效措施进行低噪声设计,就可以避免多次反复设计和试制,降低设计费用,加快制造进度。薄壳结构在汽车、船舶、水下航行结构等领域广泛使用,研究复杂薄壳结构在宽频域声振特性的预测及控制技术,对国民经济和国防事业具有重大的意义。本文以复杂薄壳结构为研究对象,研究了加筋板结构、夹层结构、基座结构、圆柱壳体及支撑结构与船舶模型在宽频范围的振动与声辐射特性及控制技术；提出了一种阻振性能优良的新型空心阻振结构；研制了一种具有宽频高阻尼特性的丁基橡胶复合阻尼减振胶板,从工程应用角度充分揭示了其对薄壳结构的减振性能；设计了内含多个设备支撑基座的圆柱壳体实验模型装置,研究了圆柱壳体内支撑结构的振动传递与辐射噪声特性；提出了支撑结构的复合阻振技术,开展了复杂薄壳结构在宽频域的声振特性预报,取得了良好的减振降噪效果。本文主要研究内容及结论如下：(1)基于复杂结构中高频声振性能分析的FE-SEA混合法,提出用特征尺寸与波长的比值即特征尺度比△划分FEM、SEA和FE-SEA混合法的有效频率区间,提高了建立复杂薄壳结构FE-SEA混合模型的效率。(2)提出了一种新型空心阻振结构,开展了阻振机理及数值计算和实验研究。与实心阻振结构相比,空心阻振结构的阻抗失配加剧,阻振效果提高,有效阻振频率向低频移动,可拓宽阻振频率范围。薄壳结构的加强筋可在一定程度上降低板结构的低频振动,而阻振结构主要对中高频振动具有优良的阻振性能。(3)以丁基橡胶为主要原材料研制的自粘性复合阻尼减振胶板,对于汽车、船舶等薄壳板筋结构,在宽频范围具有良好的阻尼减振性能。粘贴该复合阻尼减振胶板后,薄壳结构在宽频范围的平均结构损耗因子显著增加,阻尼减振效果随着传播距离的增加而增加。(4)设计了内部具有3类设备支撑基座的水下圆柱壳体实验模型装置,采用传递函数灵敏度分析方法,对圆柱壳体结构有限元模型进行修正。修正后圆柱壳体、平台结构前10阶固有频率的计算误差分别小于8%、2%,传递函数计算与实验结果的趋势基本一致。在此基础上,分析了支撑结构参数对圆柱壳体低频振动传递特性的影响规律,为支撑结构声学设计提供了基础。(5)通过基座至圆柱壳体结构的振动传递特性分析,揭示了基座类型、结构参数和布置位置对振动传递特性的影响。基座至圆柱壳体表面的振动传递函数、传递率与基座及圆柱壳体的结构振动模态参数有关,在低频时受基座和圆柱壳体结构振动模态的影响较为明显；相同类型的基座,至圆柱壳体表面的等效传递率较接近,基座局部结构参数的调整对等效传递率的影响较小；用机械导纳与传递率为评价指标,所得到的基座至壳体表面的机械导纳与传递率分布的趋势及基本特征一致;在中高频时,提出了采用等效机械导纳或等效传递率评价圆柱壳体表面的平均振动特性。(6)提出了质量阻振与阻尼减振相结合的复合阻振技术,开展了圆柱壳体模型支撑结构的复合阻振性能研究。结果表明复合阻振技术较单独刚性阻振、阻尼减振技术具有一定优势,可提高减振降噪效果并拓宽有效减振频率范围。本文工作发展了薄壳结构阻振结构的结构形式,研究了薄壳结构的质量阻振性能,研究了丁基橡胶复合阻尼材料的阻尼减振性能,提出了支撑结构的复合阻振技术,研宄了复杂薄壳结构的宽频声振性能混合法建模及数值预报方法,深化了支撑结构的振动传递控制技术,为提高复杂薄壳结构的声学设计水平进行了创造性的工作,取得了一系列具有工程实用价值的结论和成果,对于汽车、船舶等复杂薄壳结构的低噪声设计具有参考价值。更多还原

【Abstract】 With the development of industry, the operating power of dynamic machinery equipment increases, and its vibration energy is heightened. Nevertheless, the engineering structure develops towards light and thin increasingly, which makes the structural vibration and sound become more severe. Therefore, in the product design stage, provided that the vibro-acoustic characteristics of product were predicted validly, the effective measures to proceed low noise design were carried out in advance, the designs and trial-manufactures repeatedly would be avoided, the cost of design would be reduced and the schedule of manufacture would be accelerated. As the thin shell structure has been widely used in automobile, ship hull and underwater navigation structure and so on, the prediction and control technology on the vibro-acoustic characteristics of complex thin shell structure in wide frequency domain will show great significance not only in astronavigation, automobile, ship, but also in machinery industry.In this paper, taking complex thin shell structure as research object, the vibration and radiation characteristics and control technology of stiffened plate (sheet-beam) structure, sandwich structure, base structure, cylindrical shell and its supporting structure and ship model have been studied in the wide range of frequency. A new pattern hollow blocking mass structure with excellent vibration-isolating performance was put forward. Besides, a kind of butyl-rubber composite damping rubber sheet with high damping characteristics was developed, and whose vibration damping performance in thin shell structure was uncovered from the perspective of engineering application. The cylindrical shell experimental model containing several equipment supporting pedestals was designed, and the vibration transmission and noise radiation characteristics of these inner supporting structures were studied. In addition, the composite blocking technology of supporting structure was put forward, a series of vibro-acoustic prediction were carried out on the complex thin shell structure such as cylindrical shell and ship cabins in the wide range of frequency, and a good effect on reducing vibration and noise was obtained. The main research contents and conclusions of this paper as follows:Base on the hybrid FE-SEA method applied on the vibro-acoustic characteristic analysis of complex structure in the mid-high frequency domain, the parameters of the ratio of characteristic dimension to wavelength used to divide each effective frequency domain of FEM, SEA and hybrid FE-SEA method was defined, which improved the efficiency of building complex thin shell structural hybrid FE-SEA model.A new type pattern hollow blocking mass structure was put forward, whose vibration-isolating mechanism was studied by numerical calculation and experiment. Compared with solid blocking mass, the impedance mismatching of hollow blocking mass was increased, which lead to its blocking performance be improved. The effective blocking frequency shifted toward low frequency domain, which widened the blocking frequency domain of hollow blocking mass. The stiffeners of thin shell structure could reduce the vibration of plates in low frequency to some extent, while the blocking mass had an excellent vibration-isolating performance in mid-high frequency domain.A kind of self-adhesive composite damping rubber sheet, with butyl rubber as main raw material, has good damping vibration attenuation performance for the thin shell structure such as ship in the wide range of frequency. After pasted with these composite damping sheets, the average structural loss factor of thin shell structure increased significantly in the wide range of frequency, whose damping performance increased with the propagation distance.One underwater cylindrical shell experimental model containing3kinds of equipment supporting pedestals was designed. By the analysis method of transfer function sensitivity, the finite element model of cylindrical shell structure was amended. The calculation errors of the first10order natural frequencies of the cylindrical shell and the internal platform structure were less than8%and2%respectively after amended. Besides, the trends of calculated transfer function were basically identical with experimental results. On this basis, the influence rule on the vibration transmission characteristics of supporting structures inside the cylindrical shell in low frequency was analyzed, which provided the foundation for the acoustic design of supporting structures.By analyzing the vibration transmission characteristics from pedestals to cylindrical shell structure, the influences on vibration transmission characteristics of pedestal type, structural parameters and layout were revealed. The vibration transfer function and transmissibility from pedestals to cylindrical shell structure had connection with structural modal parameters, which was influenced by pedestal and cylindrical shell structural vibration modes obviously in low frequency. The equivalent transmissibility from the same type pedestals to the cylindrical shell approached identical much the same, and the adjustment of the local structural parameters of pedestals also had a little effect on the equivalent transmissibility. Taking mechanical admittance and transmissibility as evaluation index, the distributional trends and essential characteristics of mechanical admittance and transmissibility from pedestals to the cylindrical shell were identical. In the mid-high frequency domain, taking the equivalent mechanical admittance and equivalent transmissibility as evaluating the average vibration characteristics of cylindrical shell was provided.The composite vibration-isolating technology combining blocking mass and damping vibration attenuation was provided, and the study on the composite blocking performance of the internal supporting structures was carried out. The results showed that the composite vibration-isolating technology was advantageous than rigid blocking or damping vibration attenuation technology solely, which could improve the vibration and noise reduction performance and widened the effective vibration-isolating frequency domain.In this paper, the structural styles of thin shell structural blocking mass was developed, and a kind of butyl-rubber composite damping rubber sheet was also developed. Based on studying the mass blocking and damping vibration attenuation performance, the composite vibration-isolating technology of inner structure was put forward, and the vibro-acoustic performance hybrid modeling and numerical prediction method on complex thin shell structure in wide frequency domain was studied, which deepened the vibration transmission control technology of inner structure and carried out creative work in order to improve the acoustic design level of complex thin shell structure. Thus a series of conclusion and achievements with engineering practical value were obtained, which had a reference value in the low noise design of the complex thin shell structures in automobile and ship hull and so on.更多还原