【作者】 乔宇锋；

【导师】 黄其柏；

【作者基本信息】 华中科技大学 ， 机械设计及理论， 2007， 博士

【摘要】 由于结构辐射声是产品的主要噪声源之一,因此产品设计者和制造者经常面临着用户对其产品结构辐射噪声的负面评价,这种用户的反映就是结构辐射声品质问题。声品质是用户对产品辐射声接受度的心理感觉反映,也是产品一系列性能的综合反映;其包含响度、粗糙度、波动度等一系列参数,并以不同的感受影响着人类的听觉心理。另一方面,声品质还可应用于其他用途,例如可通过声波动度判断汽车传动系统工作状态的平顺性。因此,结构辐射声品质设计成为产品设计中的一个重要问题,这类问题的研究对低噪声产品的设计具有重要的理论意义和实用价值,对其他工程问题的解决也有着广阔的应用前景。本文运用以解析法为主、结合数值计算的方法,对不同形式的板结构声辐射特性及其声品质进行了系统的研究。建立了有限大板结构在无障板情况下的声辐射模型,分析了刚性障板对声辐射的影响规律;建立了板结构声辐射解析模型,研究了不同边界对板结构声辐射的控制规律;利用Zwicker响度模型和修正的PEAQ(Perceptual Evaluation of Audio Quality)方法,建立了板结构辐射声响度预测模型;发展和完善了GDQ(Generalized Differential Quadrature)方法,建立了适用于具有复杂边界板结构的声辐射模型和声波动度预测模型,揭示了各因素对板结构辐射声波动度的影响规律;提出了主区域离散方法,建立了具有任意形状和边界条件的板结构声辐射模型和声粗糙度预测模型,揭示了各因素对板结构辐射声粗糙度的影响规律;基于刚度,建立了加筋板结构声辐射及其声响度预测模型,揭示了加强筋对板结构辐射声响度的影响规律;提出了一个新的研究领域——结构辐射声品质主动控制,研究了一种控制板结构辐射声响度的主动控制策略。通过本文的理论分析与数值计算,获取了一系列有价值的研究结果,为板结构声辐射及其声品质设计提供了理论依据,也为产品虚拟声设计奠定了基础。与现有研究成果相比,本文的研究成果主要体现在以下几个方面:建立了在无刚性障板时有限大板结构声辐射模型,提出了当边界条件中含有弹性边界时结构声辐射的解析求解方法,利用表示辐射声压和结构模态耦合系数的双重积分,通过计算所得的声强级结果与有刚性障板时结构声辐射的数值计算结果相对比,揭示了刚性障板对结构声辐射的影响规律。为进一步研究刚性障板对结构声辐射的影响,利用能量的观点,采用振动速度平方均值和声辐射效率为参考基准,揭示了有无障板两种情况下结构声辐射差异的原因。建立了适用于不同边界条件的板结构声辐射解析模型,并研究了边界条件对结构声辐射及声响度的影响。以五种不同边界条件的板结构声辐射为例,利用本文推导所得的解析模型,通过数值计算对比分析了简支、固支、自由三种形式的边界条件及其组合形式对板结构声辐射的影响;分析了不同激励力位置和板厚对板结构声辐射的影响规律。另一方面,由于人类听觉对声音频率的选择接收特性,边界条件对结构辐射声响度的影响与对物理声的影响有很大不同。基于Zwicker响度模型和修正的PEAQ方法,利用数值计算结果,揭示了简支、固支、自由三种形式的边界条件对结构辐射声响度的影响规律。通过计入人类听觉对频率的选择性接收特性,分析了边界条件对声功率级、声功率密度和特征频带声强级的影响,揭示了边界条件对结构声辐射和声响度不同影响的差异来源。这些研究为结构辐射响度预测和设计提供了解析模型。对于结构辐射声,当其周围声源所影响而被调制时,将产生两个均可独立处理的声品质参数:波动度和粗糙度。发展和完善了GDQ方法,建立了适用于具有复杂边界的结构声辐射及其声波动度的解析计算模型。利用本文所建立的板结构辐射声波动度解析模型,揭示了调制频率、调制度和板结构模态密度等参数对辐射声波动度的影响规律,为复杂边界条件下板结构辐射声波动度设计提供了预测方法。为研究更具一般意义的板结构形式,提出了主区域离散方法,建立了具有任意边界和形状的板结构声辐射及其声粗糙度解析计算模型。利用本文所建立的板结构辐射声粗糙度模型,揭示了调制音频率、声压级和板结构模态密度变化对辐射声粗糙度的影响规律。利用分层三角法函数和修正的PEAQ方法,建立了一般形式的正交加筋板结构声辐射及其声响度解析模型。以三种不同加强筋形式的板结构为例,揭示了加强筋及其组合形式对辐射声响度的影响规律,分析了加强筋对声功率级及特征频带声强级的影响,说明了加强筋对物理声和声响度不同影响的差异原因,也研究了在加筋情况下板结构模态密度对结构辐射声响度的影响规律。研究结果为通过加强筋控制板结构辐射声响度提供了理论模型和预测方法。研究了适用于结构辐射声响度的主动控制策略。利用声辐射模态理论,建立了适用于主动控制的辐射声响度模型,并据此提出了一种声响度主动控制策略。利用四种具有不同边界条件的矩形板结构,通过其辐射声响度计算结果,验证了该控制策略的有效性,并分析了不同边界条件对在同种控制策略表现在结果上的差异。这些研究结果为主动控制在结构辐射声品质设计中的应用提供了理论依据和预测方法,也表明了结构辐射声品质主动控制与结构振动主动控制和声辐射主动控制有着很大差异。更多还原

【Abstract】 Due to the structural noise is one of the main noise sources, designers and manufacturers are often faced with negative reactions to the sound or noise radiated from the product. A typical response to such reactions is confusion due to the“structural sound quality”of the problem. For the product, sound represents a more complex set of attributes, both aesthetic and functional, the structural sound quality becomes a key problem in product design. Sound quality includes a series of parameters, such as loudness, fluctuation strength and roughness, etc. These parameters influence the human hearing sensation by different ways. On the other hand, sound quality has other useful applications in engineering. For example, one can judge the status of the automobile power transfer system by the help of the fluctuation strength radiated form it. Therefore, for low noise and high performance product design, the study on structural sound quality is crucial on theory. This study also has wide application future on other engineering problems.Analytical method is the main method used in this dissertation. Integrated with numerical method, this dissertation does a deep study systemically for the radiated sound and sound quality from the plate or plate-like structures with different forms. At first, the structural sound radiation model is established for the un-baffled finite plates. Because the different boundary conditions have different effects on the radiated sound, the analytical model is prompted for the calculation of the sound radiated from the plates. Based on the Zwicker loudness model and the corrected PEAQ (Perceptual Evaluation of Audio Quality) method, a model of sound loudness, which is radiated from the plates, is established for forecasting. For calculating the sound radiated from plates with mixed boundary conditions, the GDQ (Generalized Differential Quadrature) method is developed and corrtected in this dissertation. Based on the GDQ method, the model of sound radiation and sound fluctuation strength from the plates with mixed boundary conditions are established. The parameters, which affect the radiated sound fluctuation strength, are also discussed. Using the main domain discretization method prompted in this dissertation, the model of the sound radiation and sound roughness from the plates with arbitrary geometry forms or arbitrary boundary conditions is established. For revealing the effects of the stiffeners and its combined forms on the sound loudness radiated from the stiffened plates, the model of sound radiation and sound loudness from the stiffened plates is established. A new research field, active control of structural sound quality, is prompted in this dissertation. Based on the theory of sound radiation mode, this dissertation develops an active control strategy to control the sound loudness radiated from the plates. Some valuable study results are obtained through the theoretical analysis and numerical calculation in this dissertation. These results provide the theoretical foundation stone for the design of the structural sound quality and the virtual product radiated sound design.Comparing with the current research results, the features obtained in this dissertation are mainly as follows:The model of the sound radiation characteristic from the un-baffled rectangular plates is established. An analytical method is prompted to calculate the sound radiated from the plate with elastic support boundary conditions. The sound power level radiated from the un-baffled plates is numerically calculated by using a double layer integral representation of the sound radiation pressure and the modal coupling coefficients. The sound power level radiated from the baffled rectangular plates with the same boundary conditions are calculated in numerical experiments for comparison. From the viewpoint of energy, average velocity square of the un-baffled and the baffled rectangular plates with different boundary conditions is calculated, respectively. The relationship of sound radiation efficiency between the un-baffled and the baffled rectangular plates is deduced.The effects of boundary conditions on sound radiation characteristics from the rectangular plates are studied. Using analytical method, five different boundary conditions are analyzed and calculated in numerical experiments as examples. The results reveal the effects of simple support, free support and clamped support on the sound radiated from the rectangular plates. Rectangular plates with different point force location and different plate thickness are calculated for verifying the effects of boundary conditions. On the other hand, because of the frequency selectivity of human hearing, the effects of boundary conditions on sound quality are different from the one on physical sound. Based on the Zwicker’s loudness model and the corrected PEAQ method, the sound loudness radiated from the vibrating plates and the effects of simple support, clamped support and free support on sound loudness are separately studied. The effects of boundary conditions on sound intensity level, sound intensity density and critical-band level are also studied under the condition of taking the frequency selectivity of human hearing system into account. The transformation progress of sound intensity level to sound loudness radiated from the rectangular plates, which is caused by the human hearing frequency selectivity characteristic, is illustrated in this dissretation. The research results provide analytical method for the forecasting and design of the sound loudness radiated from the plates or plate-like strucutres.For the structural sound, two separate psycho-acoustical parameters, sound fluctuation strength and sound roughness, appears when the radiated sound is modulated by other sounds. The generalized differential quadrature method is developed for calculating the sound radiated from the forced vibrating rectangular plates with mixed boundary conditions. The fluctuation strength of the radiated sound, which is modulated by another sound near the plates, is studied. The effects of the modulation frequency and the modulation degree on the sound fluctuation strength are revealed. The effects of the radiated sound frequency and the structural modal density are also studied and compared, respectively. The numerical results are presented to show the characteristics of the fluctuation strength of the modulated sound radiated from the rectangular plates with mixed boundary conditions. For further generalizing, this dissertation reveals the effects of the modulation-sound pressure level and the modulation-sound frequency on the modulated sound roughness radiated from the rectangular plates with non-uniform boundary conditions. A generalized method is developed to calculate the radiated sound from such plates. Using this method, the sound roughness is calculated and compared with different modulation-sound frequency and modulation-sound pressure level, including the radiated sound frequency. Moreover, the effect of the plate mode density on the sound roughness is also illustrated.This dissertation reveals the effects of the stiffeners on the radiated sound loudness from the stiffened rectangular plates. Based on the hierarchical trigonometric functions and the corrected PEAQ method, the sound loudness radiated from different stiffened plates and the effects of the stiffeners’form are studied, respectively. The effects of the stiffener on the radiated sound intensity level and the critical-band level are also studied. Due to the frequency selectivity of human hearing, the difference of the physical sound and the human hearing sensation are illustrated. Moreover, the effect of the mode density on the radiated sound loudness is also illustrated. The results provide theoretical model and a forecasting method for the controlling of the structural sound loudness by stiffeners.A new research filed, active control of structural sound quality, is prompted. The active loudness control of the sound radiated from the rectangular plates is studied. Basing on the radiation modes, the sound loudness model is developed for the active loudness control. According to the radiation modes and the developed sound loudness model, an active loudness control strategy is prompted. By comparing the different boundary conditions on the edge of the plate, the effects of the boundary conditions on the active sound loudness control are also illustrated. The calculation results show that the radiated sound loudness is effectively controlled by the strategy. The results also reveal that, for the reason of the frequency selectivity of the human hearing, the active control of structural radiated sound loudness is quite different from the active control of structural vibration and the tradiational active control of noise.更多还原