一种基于等效源法的表面阻抗现场测量方法
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摘要
针对使用近场声全息技术测量表面阻抗时必须在消声室内测量的问题,提出一种基于等效源法的表面阻抗现场测量方法。该方法在材料上方构造一个虚拟腔体,且在腔体内部使用封闭的测量面采集声压,利用基于等效源法的近场声全息技术计算材料表面阻抗。选用单极子和偶极子作为主动声源,对测量环境添加干扰声源进行仿真分析,结果证明了该方法的有效性以及对测量环境的适应性。同时对主动声源以及等效源的位置进行分析,结果表明主动声源在材料表面上方0.2 m～0.4 m处位置为最优,等效源封闭面的上下表面关于材料表面对称,且距离材料表面0.075 m～0.175 m时,测量效果最佳。
Currently existing acoustic impedance measurement methods based on nearfield acoustic holographyare highly dependent on the anechoic chamber and need to measure the material properties in large areas. A surface impedance measurement method based on equivalent source approach is proposed in this paper. In this method, a virtual cavity above the material is constructed. Meanwhile, the closed measurement surface is used to collect the sound pressure inside the virtual cavity. The near-field acoustic holography technique based on the equivalent source method is used to calculate the surface impedance. Monopole and dipole are selected as the active sources, and the interference sources are simulated and analyzed in the measurement environment. The validity of the method and the adaptability to in-situ measurement environment are proved by the results. The analysis of the locations of active sound source and the equivalent source shows that the location of 0.2 m-0.4 m above the material surface is the optimum for the active sound source; when the upper and lower surfaces of the closed surface of the equivalent source are symmetrical about the surface of the material and are 0.075 m-0.175 m away from the surface, the measurement effect is the best.
Currently existing acoustic impedance measurement methods based on nearfield acoustic holographyare highly dependent on the anechoic chamber and need to measure the material properties in large areas. A surface impedance measurement method based on equivalent source approach is proposed in this paper. In this method, a virtual cavity above the material is constructed. Meanwhile, the closed measurement surface is used to collect the sound pressure inside the virtual cavity. The near-field acoustic holography technique based on the equivalent source method is used to calculate the surface impedance. Monopole and dipole are selected as the active sources, and the interference sources are simulated and analyzed in the measurement environment. The validity of the method and the adaptability to in-situ measurement environment are proved by the results. The analysis of the locations of active sound source and the equivalent source shows that the location of 0.2 m-0.4 m above the material surface is the optimum for the active sound source; when the upper and lower surfaces of the closed surface of the equivalent source are symmetrical about the surface of the material and are 0.075 m-0.175 m away from the surface, the measurement effect is the best.
引文
[1]朱有剑,张勇,熊文波.基于传递函数法的阻抗管吸声系数测量系统研究[J].声学与电子工程,2012(4):27-31.
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[4]毕传兴,林汪林,张永斌.材料吸声性能自由场测量方法综述[C].船舶水下噪声学术讨论会,2017.
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[8]ZHANG Y B,LIN W L,BI C X.A technique based on the equivalent source method for measuring the surface impedance and reflection coefficient of a locally reacting material[C].INTER-NOISE and NOISE-CON Congress and Conference Proceedings,2014.
[9]NAVA G P,YASUDA Y,SATO Y,et al.On the in situ estimation of surface acoustic impedance in interiors of arbitrary shape by acoustical inverse methods[J].J Agr Sci Tech-IRAN.,2009,30(2):100-109.
[10]BI C X,HU D Y,ZHANG Y B,et al.Identification of active sources inside cavities using the equivalent source method-based free-field recovery technique[J].J.Sound Vib.,2015,346(1):153-164.
[11]张永斌,毕传兴,陈剑,等.基于等效源法的平面近场声全息及其实验研究[J].声学学报,2007(6):489-496.
[12]胡定玉,李再帏,方宇.非自由声场中目标声场还原与重建的等效源方法[J].声学学报,2017,42(4):465-475.
[13]傅初黎,李洪芳,熊向团.不适定问题的迭代Tikhonov正则化方法[J].计算数学,2006(3):237-246.
[14]HANSEN P C,O'LEARY D P.The use of the L-curve in the regularization of discrete ill-posed problems[J].SIAM J.Sci.Comput.,2006,14(6):1487-1503.
[15]ZEA E,ARTEAGA I L.Single layer planar near-field acoustic holography for compact sources and a parallel reflector[J].J.Sound Vib.,2016,380(C):129-145.
[2]INTERNATIONAL STANDARDS ORGANIZATION.ISO 10534-1:Acoustics-Determination of sound absorption coefficient and impedance in impedance tubesPart 1:Method using standing wave ratio[S].2001.
[3]陶猛,王广玮.驻波管中测量声学材料的隔声量[J].噪声与振动控制,2013,33(5):210-212+216.
[4]毕传兴,林汪林,张永斌.材料吸声性能自由场测量方法综述[C].船舶水下噪声学术讨论会,2017.
[5]TAMURA M.Spatial Fourier transform method of measuring reflection coefficients at oblique incidence.I:Theory and numerical examples[J].J.Acoust.Soc.Am.,1990,88(5):2259-2264.
[6]TAMURA M,ALLARD J F,LAFARGE D.Spatial Fourier-transform method for measuring reflection coefficients at oblique incidence.II.Experimental results[J].J.Acoust.Soc.Am.,1995,97(4):2255-2262.
[7]聂佳.基于主动声全息的全向声反射系数测量方法理论仿真与实验研究[D].哈尔滨:哈尔滨工程大学,2006.
[8]ZHANG Y B,LIN W L,BI C X.A technique based on the equivalent source method for measuring the surface impedance and reflection coefficient of a locally reacting material[C].INTER-NOISE and NOISE-CON Congress and Conference Proceedings,2014.
[9]NAVA G P,YASUDA Y,SATO Y,et al.On the in situ estimation of surface acoustic impedance in interiors of arbitrary shape by acoustical inverse methods[J].J Agr Sci Tech-IRAN.,2009,30(2):100-109.
[10]BI C X,HU D Y,ZHANG Y B,et al.Identification of active sources inside cavities using the equivalent source method-based free-field recovery technique[J].J.Sound Vib.,2015,346(1):153-164.
[11]张永斌,毕传兴,陈剑,等.基于等效源法的平面近场声全息及其实验研究[J].声学学报,2007(6):489-496.
[12]胡定玉,李再帏,方宇.非自由声场中目标声场还原与重建的等效源方法[J].声学学报,2017,42(4):465-475.
[13]傅初黎,李洪芳,熊向团.不适定问题的迭代Tikhonov正则化方法[J].计算数学,2006(3):237-246.
[14]HANSEN P C,O'LEARY D P.The use of the L-curve in the regularization of discrete ill-posed problems[J].SIAM J.Sci.Comput.,2006,14(6):1487-1503.
[15]ZEA E,ARTEAGA I L.Single layer planar near-field acoustic holography for compact sources and a parallel reflector[J].J.Sound Vib.,2016,380(C):129-145.