带有孔或隙隔声结构的声传播特性计算方法研究

发布时间：2018-10-17 10:19

【摘要】：隔声结构声传播特性计算是产品低噪声设计阶段的重要环节,也是产品噪声控制工程中的降噪依据。由于结构、工艺和密封效果的原因,隔声构件上存在孔洞或缝隙(下文简称“孔隙”)不可避免。如汽车车门与车身间形成的带缝隙结构、汽车发动机舱和驾驶舱间带孔的隔声墙、航空发动机进气道的声衬等。研究工程中这一类带孔隙隔声结构的声传播特性、建立声传播特性与孔隙几何参数间的关系、推导带孔隙隔声结构声传播特性计算方法,对产品低噪声设计和降噪工程的实施具有重要意义。本文以国防973子项目研究为背景,以隔声结构上的孔隙为研究对象,对多种形状孔隙在法向入射、倾斜入射和散射声场入射时声传播特性计算方法进行深入研究。建立了复杂孔隙的声传播特性计算公式,给出了大尺寸矩形或圆形孔隙声传播特性全频段快速计算方法。在此基础上,提出了内有平均流的孔隙声传播特性计算方法。本文的主要研究工作和创新性成果如下： 1)复杂孔隙的声传播特性计算方法研究。平面波假设下提出了复杂孔隙声传播特性计算的一般方法,建立了该计算方法的解析公式。通过直孔、锥孔、突变截面孔等类型孔的声传播特性解析计算、算例对比,验证了该方法的正确性；分析了孔隙几何参数对其声传播特性的影响,为带复杂孔隙隔声结构的设计提供了一种通用的解析计算方法,提高了其计算适应性。 2)大尺寸孔隙声传播特性全频带计算方法研究。当分析频率很高或孔隙尺寸较大时,计算频率往往会超过孔隙的截止频率,平面波假设下的计算模型失效。本文推导并建立了全频带矩形和圆形孔隙的声传播特性解析计算公式,解决截止频率以上孔隙的声传播特性计算问题,较之已有的解析计算方法具有显著的速度优势。计算结果与已有解析方法计算结果、声学有限元法仿真结果和实验结果对比,具有很高的吻合度,验证了其正确性；同时,还研究了孔隙几何参数对其声传播特性的影响,用工程实例检验了本方法的准确性和优越性,为带此类孔隙隔声结构的设计提供依据。 3)隔声结构上孔隙出入口界面处声辐射阻抗计算方法研究。带孔隙隔声结构的声传播计算结果与孔入口和出口界面处声辐射阻抗密切相关,声辐射阻抗受辐射体表面振动模态的控制。本文提出一种考虑辐射体表面振动模态的声辐射阻抗计算方法,用变量代换法将四重积分降为二重积分,用极坐标变换方法解决了该类声辐射阻抗计算中的奇异值问题,降低了声辐射阻抗求解的复杂程度,为带孔隙隔声结构的声传播特性计算提供重要支持。 4)考虑结构声透射的带孔隙隔声结构声传播特性计算的应用研究。采用Patch加权声传递率方法开展考虑结构声透射的带孔隔声结构声传播特性计算,将孔用Patch方法附加到无孔隙隔声板上,获得孔声泄露的量化数值,从而得到含孔隔声结构的总声传递率和声传递损失,建立了一种考虑结构声透射的带孔隙隔声结构的声传播特性计算方法,为孔隙的存在对隔声结构声传播特性影响提供量化指标；声学有限元法仿真结果验证了本文计算方法的有效性。 5)内有平均流的孔隙声传播计算方法研究。在孔隙声传播特性计算方法的基础上,结合孔隙内有平均流的声波波动方程,推导并建立了内有平均流的孔隙声传播特性计算公式。将本文解析计算结果与声学有限元法仿真结果进行对比,验证其正确性。在此基础上初步研究了平均流对孔隙声传播特性的影响,为航空发动机声衬设计提供参考。
[Abstract]:Sound propagation characteristic calculation of sound insulation structure is an important part of low noise design stage of product, and it is also the basis of noise reduction in noise control engineering of product. Due to the structure, process and sealing effect, there is a hole or gap on the sound insulation component (hereinafter referred to as" "Porosity") inevitable. such as a belt gap structure formed between an automobile door and a vehicle body, an automobile engine compartment and a sound insulation wall with holes in the cockpit, an acoustic liner of an air engine intake duct, and the like. In this paper, the acoustic propagation characteristics of this kind of porous sound insulation structure are studied, the relation between acoustic propagation characteristics and pore geometry parameters is established, and the calculation method of acoustic propagation characteristics with pore sound insulation structure is deduced. It is of great significance for the implementation of low noise design and noise reduction engineering of products. Based on the study of the National Defense 973 Sub-project, this paper studies the acoustic propagation characteristics of various shapes and pores on the incident, oblique incidence and scattering sound field of various shapes, taking the pore as the research object in the sound insulation structure. In this paper, a formula for calculating the acoustic propagation characteristics of complex pores is established, and a full-band fast calculation of the acoustic propagation characteristics of large-sized rectangular or circular pores is given. On the basis of this, the acoustic propagation characteristics of the pore with an average flow are put forward. Methods: The main research work and innovative results of this paper The following: 1) Acoustic propagation characteristics of complex porosity In this paper, a general method for calculating the propagation characteristics of complex pore sound is put forward under the assumption of plane wave, and the calculation method is established. Through the analysis of the acoustic propagation characteristics of the types of holes such as straight holes, cone holes and abrupt faces, the correctness of the method is verified, and the acoustic propagation of the pore geometric parameters is analyzed. The influence of characteristics provides a general analytical calculation method for the design of sound insulation structure with complex porosity. Computational adaptability. 2) Large-size pore sound propagation characteristics The frequency band calculation method. When the analysis frequency is high or the pore size is large, the calculation frequency tends to exceed the cut-off frequency and plane wave hypothesis of the pore. In this paper, the calculation formula of the acoustic propagation characteristics of the full-band rectangle and circular aperture is derived, and the calculation of the acoustic propagation characteristics of the above-cut-off frequency is solved, compared with the existing analytical calculation method. The results are compared with the results of the existing analytical method, the simulation results of the acoustic finite element method and the experimental results, the accuracy is verified, and meanwhile, the pore geometry parameters are also studied. The influence of acoustic propagation characteristics, the accuracy and superiority of this method are verified by engineering examples, and it is a sound insulation knot with such pores. The design of structure provides the basis for the design of sound insulation structure. Acoustic radiation impedance calculation method is studied. The results of acoustic propagation with pore sound insulation structure are closely related to the acoustic radiation impedance at the entrance and exit interface of the hole, and the acoustic radiation impedance is affected by radiation. In this paper, a method for calculating the vibration mode of the surface of the radiator is proposed. The method of calculating the acoustic radiation impedance of the vibration mode of the surface of the radiator is proposed. The four heavy integral is reduced to the double integral by the variable substitution method. The singular value problem in the calculation of the acoustic radiation impedance is solved by using the polar coordinate transformation method, and the noise is reduced. The Complexity of the Solution of Radiation Impedance and the Sound Transmission with the Pore Sound Insulation Structure providing important support for the calculation of broadcasting characteristics. 4) taking into account the sound transmission of the structure with porosity and sound insulation In this paper, the acoustic propagation characteristics of the structure acoustic transmission are studied. The acoustic propagation characteristics of the perforated sound insulation structure considering the structure acoustic transmission are calculated by using the Patch weighted sound transmission rate method, and the hole patch method is added to the non-porous sound isolating plate to obtain the quantized value of the acoustic leakage of the hole, so as to obtain the sound insulation containing the hole. Based on the total acoustic transmission rate and acoustic transmission loss of the structure, a method for calculating the acoustic propagation characteristics of the sound transmission with pore structure is established, which provides a quantitative index for the influence of the existence of the porosity on the acoustic propagation characteristics of the sound insulation structure, and the acoustic finite element method is used to simulate the structure. The validity of this method is verified. In this paper, the acoustic wave propagation method of the average flow is studied. On the basis of the calculation method of the acoustic propagation characteristics of the pore, the wave equation of the acoustic wave with the average flow in the pores is combined and deduced and established. In this paper, the calculation formula of the acoustic propagation characteristics of the pore sound with an average flow is presented. The results obtained in this paper are compared with the acoustic limit. The simulation results of the element method are compared and the correctness is verified. On the basis of this, the characteristics of the average flow on the acoustic propagation of the pore are studied.
【学位授予单位】：合肥工业大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TB535.2

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