低频智能吸声结构的研究
文献类型：学位论文
| 作者 | 常道庆 |
| 学位类别 | 博士 |
| 答辩日期 | 2008-02-24 |
| 授予单位 | 中国科学院声学研究所 |
| 授予地点 | 声学研究所 |
| 关键词 | 低频噪声 智能结构 压电分流阻尼技术 粘弹性橡胶材料 微穿孔板 |
| 其他题名 | Research on smart structures for low frequency sound absorption |
| 学位专业 | 声学 |
| 中文摘要 | 传统的控制低频吸声的方法主要是利用各种共振腔或者板式共振吸声结构，但由于阻尼不够，往往需要附加约束阻尼层或者泡沫材料来改善其吸声效果。但这会带来其它的不利影响，如质量增加，环境污染等。因此有必要探索其它控制低频吸声的方法，其中智能结构就是一种选择。压电分流阻尼技术是90年代发展起来的一种智能控制技术，该技术由于不需要复杂的控制算法，实现起来简单、鲁棒性好，因此在低频减振领域受到重视。但是在声控制领域，这种技术研究的还很不深入。基于此，本文研究了压电分流阻尼技术在声吸收方面应用的可行性。主要研究内容和创新点包括以下几个方面： （1）基于板的弯曲共振和压电分流阻尼技术，提出一种新的低频窄带吸声结构：智能板式共振吸声结构。建立了智能板式共振吸声结构的理论分析模型。根据压电陶瓷薄片外接分流电路时的等效柔顺性系数，应用拉格朗日方程导出了粘有压电陶瓷片薄板的运动方程。方程中包含薄板和压电片的质量、弹性、阻尼以及压电片分流电路的电阻和电感。导出了结构表面阻抗和吸声系数与分流电路参数之间的关系。利用数值计算和实验方法研究了压电分流阻尼技术控制薄板吸声特性的机制，分析了串/并联电阻和电感与薄板吸声系数、相对声阻和相对声抗之间的关系。数值计算和实验结果取得了良好的一致性。通过调节分流电路中电感和电阻等参数，可使电路谐振和机械谐振出现强耦合，分流电路中的电阻可以为整个系统提供阻尼的作用，可以有效地调节相对声阻，而分流电路中的电感则可以起到调谐的作用，可以调节系统结构的相对声抗。适当调节电阻和电感不仅可以明显提高薄板一阶模式频率处的吸声系数，并且可以调出两个吸声峰，从而有效地增加吸声频带的宽度。理论分析和实验分析表明，压电分流阻尼技术可以有效地应用于低频吸声控制。 （2）分析了压电复合材料在水下的吸声特性，与粘弹性橡胶材料在低频的吸声特性作了对比。根据压电本构方程，得出了均匀压电材料层外接分流电路时的传递矩阵，与粘弹性橡胶材料层的传递矩阵统一到一个形式中。并利用得到的传递矩阵，对压电材料层以及压电材料和橡胶材料复合吸声结构的吸声特性进行了数值计算分析。计算结果表明，在无源电路情况下，只能得到窄带的吸声效果。而通过运算放大器实现的负电容分流电路，则可以得到低频宽带的吸声效果。 （3）研究了压电分流阻尼技术与微穿孔板结合控制吸声的问题。建立了复合吸声结构的分析模型，给出了计算复合结构吸声系数的理论计算公式。对复合结构在不同空腔下的吸声特性做了数值分析和实验分析，理论和实验取得了良好的一致性。理论和实验结果表明：利用薄板的弯曲可以拓宽微穿孔板的吸声频带宽度，但两吸声峰之间会存在吸声波谷，而利用压电分流阻尼技术可以改善两吸声峰间的吸声特性。 |
| 英文摘要 | The traditional approach to the control of low frequency noise uses passive techniques such as cavities covered with a faceplate to absorb the undesired noise. These absorbers are often ineffective at low frequencies due to the insufficient damping. In order to add damping, the faceplate is usually attached with constrained layers and the cavities are filled with fiber materials. These treatments may result in many deficiencies such as extra weight and environmental pollution. Therefore, it is necessary to develop new techniques for the control of low frequency noise. The piezoelectric shunt damping technique has the advantages of efficiency, simplicity and stability and receives much attention in the area of vibration control since early nineties. However, researches on sound absorption using shunt damping receive only little attention. In this thesis, the potential of low frequency sound absorption using piezoelectric shunt damping technique is extensively investigated. The main contents and contributions of the thesis are summarized below: (1) A structure, namely Smart Panel Resonant Sound Absorber (SPRSA), is presented for the purpose of narrow band sound absorption. The structure is composed of a thin plate and a piezoelectric wafer. The analytical model of SPRSA is developed, where the governing equations for the flexural vibration of the plate with piezoelectric wafer attachment shunted with RL circuits are derived using Lagrange’s approach. The equations take into account not only the mass, stiffness and structural damping for the plate and the wafer, but also the electrical resistance and electrical inductance of the RL circuits. Based on the governing equations derived, the surface impedance and sound absorption coefficient of the plate backed with a cavity is given. The influence of RL parameters on the sound absorption of a plate shunted with piezoelectric materials is investigated using numerical analysis and experimental measurements. The effects of shunting electrical resistance and inductance on the sound absorption coefficient, acoustic resistance and reactance of the plate are thoroughly analyzed. Numerical and experimental results conclude that the sound absorption coefficient of the plate near its first mode can be significantly improved by adjusting the RL parameters. (2) The possibility of sound absorbing by an underwater piezoelectric layer shunted with electrical circuits is theoretically investigated. The transfer matrix of the piezoelectric layer shunted with electrical circuits is derived and compared with that of the viscoelastic rubber layer. Using the transfer matrices, the sound absorption of composite layers, namely piezoelectric layers and rubber layers, is examined by numerical calculation. Numerical results indicate that the sound absorption is restricted to very narrow frequency band when the piezoelectric layer is shunted with the RL circuits. However, the sound absorption band can be widened significantly when the piezoelectric layer is shunted with negative capacitance circuits. (3) A micro-perforated faceplate with piezoelectric materials shunted with passive electrical circuits is investigated as well. The sound absorption characteristics of the smart micro-perforated faceplate backed with varying cavities are theoretically and experimentally analysed. The results show that the absorption peaks due to the plate vibration could widen the absorption bandwidth of the micro-perforated plate. The combination of the micro-perforated faceplate and piezoelectric wafer can successfully improve the lowest values between the absorption peaks. |
| 语种 | 中文 |
| 公开日期 | 2011-05-07 |
| 页码 | 120 |
| 源URL | [http://159.226.59.140/handle/311008/42]  |
| 专题 | 声学研究所_声学所博硕士学位论文_1981-2009博硕士学位论文 |
| 推荐引用方式 GB/T 7714 | 常道庆. 低频智能吸声结构的研究[D]. 声学研究所. 中国科学院声学研究所. 2008. |
入库方式： OAI收割
来源：声学研究所
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