基于时间反转聚焦的水声无源材料声学性能测量
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摘要
水下声学材料构件是水声工程中使用广泛且至关重要的水下部件,不同的应用背景对材料声学性能有特殊的要求。随着材料科学的进步,粘弹性高分子材料等高性能吸声新材料在吸声降噪等水声工程领域的应用日益广泛。因而,对该类材料在水声使用环境中的声学性能测量和研究是迫切需要解决的问题。
水声无源材料的声学性能测量包括插入损失(透射系数)、回声降低(反射系数)、吸声系数等参数的测量。目前水声无源材料的声学性能测量在中高频段已经取得了重要进展,但随着主动声纳技术的发展,其探测信号频率逐渐向低频扩展,所以发展低频情况下水声无源材料声学性能的测量方法是目前水声测量领域的主要趋势。
时间反转聚焦技术充分利用了波导环境中声传播的多径特性,将多径与直达波同相位叠加,使接收信号在时间上得到了压缩,增强了信号幅度,降低了混响效应,从而可提高低频情况下接收信号的信混比。同时,时间反转技术的空间聚焦特性使信号主瓣较基于平面波波束形成(直达波单路径)的常规阵发射窄,可减小声波衍射对测量结果的影响。本文通过理论仿真分析和现场试验对时间反转聚焦测量方法进行了研究。
为了使时间反转技术能够在封闭圆柱形容器环境中得到最佳的聚焦效果,本文利用声射线的方法对该环境中的声场进行了分析,通过对主瓣分辨力和对旁瓣的抑制能力的分析,设计了最佳的接收阵和发射阵组合。
由于时反测量方法利用了波导的多径效应,为使测量结果与自由场条件相一致,通过理论分析,提出了测量参数的修正方法。分别在波导水池和压力容器环境开展了无源材料声学性能常压测量试验,并且在压力容器环境中进行了2MPa、3MPa、4MPa压力条件下的声学性能测量。通过标准试样试验结果与自由场理论结果的比较,验证了时间反转聚焦技术应用于无源材料声学性能测量的可行性。
Acoustic material components are widely used, and they are vital underwater parts in acoustic engineering. Different application backgrounds have different requirements on acoustic materials performance. With the development of material science, viscoelastic polymer materials and other high performance absorption new materials are applied widely in the absorption and noise reduction underwater acoustic engineering field. Therefore, researching the acoustic materials performance is the urgent problem.
Acoustic passive materials performance parameters include insertion loss (transmission coefficient), echo reduction (reflection coefficient), sound absorption coefficient and others. At present acoustic passive materials'performance measurement has made important progress in high frequency band, but with the development of sonar technology, the acoustic performance measurement in low frequency band is needed.
Time reversal focusing technique takes full advantage of multipath characteristics of sound propagation in the waveguide environment, summing all paths in the same phase. The temporal compression of the time-reversal focusing increases the signal strength, and improves signal reverberation ratio. The spatial compression of the time-reversal focusing makes the main lobe narrower than the plane wave beam-forming, reducing the influence of diffraction. This article researches the time reversal focus measurement method through the theory simulation analysis and field test.
In order to have the best result of time reversal in a closed cylindrical vessel environment, the best receive array and transmitting array combination is designed after the analysis of the resolution of the main lobe.
In order to make the measurement results are consistent with in free field conditions, the paper put forward the correction method of measuring parameters through the theoretical analysis. The passive materials are tested in the waveguide pool under normal pressure and the pressure vessel environment under normal,2MPa, 3MPa and 4MPa pressure. The experiment results are consistent with the theoretical value. This result proves that time reversal technology is another way to test the passive materials' performance parameters.
水声无源材料的声学性能测量包括插入损失(透射系数)、回声降低(反射系数)、吸声系数等参数的测量。目前水声无源材料的声学性能测量在中高频段已经取得了重要进展,但随着主动声纳技术的发展,其探测信号频率逐渐向低频扩展,所以发展低频情况下水声无源材料声学性能的测量方法是目前水声测量领域的主要趋势。
时间反转聚焦技术充分利用了波导环境中声传播的多径特性,将多径与直达波同相位叠加,使接收信号在时间上得到了压缩,增强了信号幅度,降低了混响效应,从而可提高低频情况下接收信号的信混比。同时,时间反转技术的空间聚焦特性使信号主瓣较基于平面波波束形成(直达波单路径)的常规阵发射窄,可减小声波衍射对测量结果的影响。本文通过理论仿真分析和现场试验对时间反转聚焦测量方法进行了研究。
为了使时间反转技术能够在封闭圆柱形容器环境中得到最佳的聚焦效果,本文利用声射线的方法对该环境中的声场进行了分析,通过对主瓣分辨力和对旁瓣的抑制能力的分析,设计了最佳的接收阵和发射阵组合。
由于时反测量方法利用了波导的多径效应,为使测量结果与自由场条件相一致,通过理论分析,提出了测量参数的修正方法。分别在波导水池和压力容器环境开展了无源材料声学性能常压测量试验,并且在压力容器环境中进行了2MPa、3MPa、4MPa压力条件下的声学性能测量。通过标准试样试验结果与自由场理论结果的比较,验证了时间反转聚焦技术应用于无源材料声学性能测量的可行性。
Acoustic material components are widely used, and they are vital underwater parts in acoustic engineering. Different application backgrounds have different requirements on acoustic materials performance. With the development of material science, viscoelastic polymer materials and other high performance absorption new materials are applied widely in the absorption and noise reduction underwater acoustic engineering field. Therefore, researching the acoustic materials performance is the urgent problem.
Acoustic passive materials performance parameters include insertion loss (transmission coefficient), echo reduction (reflection coefficient), sound absorption coefficient and others. At present acoustic passive materials'performance measurement has made important progress in high frequency band, but with the development of sonar technology, the acoustic performance measurement in low frequency band is needed.
Time reversal focusing technique takes full advantage of multipath characteristics of sound propagation in the waveguide environment, summing all paths in the same phase. The temporal compression of the time-reversal focusing increases the signal strength, and improves signal reverberation ratio. The spatial compression of the time-reversal focusing makes the main lobe narrower than the plane wave beam-forming, reducing the influence of diffraction. This article researches the time reversal focus measurement method through the theory simulation analysis and field test.
In order to have the best result of time reversal in a closed cylindrical vessel environment, the best receive array and transmitting array combination is designed after the analysis of the resolution of the main lobe.
In order to make the measurement results are consistent with in free field conditions, the paper put forward the correction method of measuring parameters through the theoretical analysis. The passive materials are tested in the waveguide pool under normal pressure and the pressure vessel environment under normal,2MPa, 3MPa and 4MPa pressure. The experiment results are consistent with the theoretical value. This result proves that time reversal technology is another way to test the passive materials' performance parameters.
引文
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[35]T.Thibieroz and C.Giangreco. Impulse acoustical measurements of the transmission coefficient of immersed panels. J.Acoust.1991,4:215-236.
[36]A. L.Van Buren. Near field calibration arrays for acoustical wave field determination. IEEE Trans. Instrum. Meas,1992, IM-41:22-26.
[37]李水,缪荣兴,唐海清,水声材料透声性能测量技术的改进。
[38]A.Parvulescu,C.S.Clay, Reproducibility of signal transmissions in the ocean, Radio Electron. Eng.1965,29:p223-228.
[39]B.Y.Zel'dovich, N.F.Pilipetsky, and V.V.Shkunov, Principle of Phase Conjugation, Springer-Verlag, Berlin,1985.
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[2]陶景桥,新型潜艇隔声去耦瓦声学性能研究及改进,哈尔滨工程大学,2005。
[3]王光荣,游蕾,潜艇隐身衣——消声瓦[J],现代舰船,2001,(05)。
[4]张宏军,邱伯华,石磊,贺鹏,消声瓦技术的现状与发展趋势[J]。舰船科学技术,2001(04)。
[5]王曼,水声吸声覆盖层理论与实验研究。哈尔滨工程大学,2004。
[6]李水,沈建新,唐海清,张晓岚。水声材料低频吸声性能的驻波管测量。
[7]李水,沈建新,唐海清,张晓岚,水声材料低频声性能的驻波管测量,计量学报,24(3)：221-224。
[8]Corbett S S.A,two-hydrophone technique for measuring the complex reflectivity of material in water-filled tubes[R].AD,1983,A138613.
[9]Seybert A F and Ross D F. J. Acoust. Soc. Am.,1979,61:1362-1370.
[10]Hideo Utsuno, Toshinlitsu Tanaka and Takeshi Fujikawa. J. Acouat. Soc. Am.1989, 86 (2):637-643.
[11]ASTM 1990 E 384-90a.
[12]ASTM 1990 E 1050-90.
[13]U. Ingard and R. H. Bolt. A free field method of measuring the absorption coefficient of acoustic materials. J. Acoust. Soc. Am.1951,23:509-516.
[14]D. J. Sides and K. A. Mulholland. The variation of normal layer impedance with angle of incidence. J. Sound Vib.1971,14:139-142.
[15]H.Tachibana, H.Yano and K. Ishii. Oblique incidence sound absorption characteristics of various absorbing materials measured by cross-correlation method. J. Acoust. Soc. Jpn.1978,34:11-20.
[16]J. C. Davis and K. A. Mulholland. An impulse method of measuring normal impedance at oblique incidence. J. Sound Vib.1979,67:135-149.
[17]Y. Miki. Application of the synchronized correlation method to the measurement of sound propagation over a ground surface. J. Acoust. Soc. Jpn.,1980, (E)1:157-166.
[18]A. J. Cramond and C. G. Don. Reflection of impulse as a method of determining acoustic impedance. J. Acoust. Soc. Am.1984,75:382-389.
[19]李水,缪荣兴.水声材料性能的自由场宽带压缩脉冲叠加法测量.声学学报,2000,25(3)：248-253.
[20]李水,缪荣兴,唐海清.消声瓦声学性能的大面积宽频带测量.声学与电子工程,2001，2：28-31.
[21]李水.水声隐身材料测量技术研究.哈尔滨工程大学硕士学位论文.2002.
[22]J. F.Allard and B.Sieben. The measurement of acoustic impedance at oblique incidence with two microphones. J. Sound Vib.1985,101:130-132.
[23]M. Minten, A. Cops and W. Lauriks. Absorption characteristics of an acoustic material at oblique incidence measured with the two-microphone technique. J. Sound Vib.1988,120:499-510.
[24]G. V. Frisk, A. V. Oppenheim and D. R. Martinez. Technique for measuring the plane wave reflection coefficient of the ocean bottom. J. Acoust. Soc. Am.1980, 68:602-612.
[25]Tanmura, Spatial Fourier transform method of measuring reflection coefficient at oblique incidence. Theory. and numerical examples. J. Acoust. Soc. Am.,1990,88(5):2259-2264.
[26]Tanmura, J F Allard and D Lafarge. Spatial Fourier transform method for measuring reflection coefficient sat oblique incidence Ⅱ. Experimental rsul ts. J. Acoust. Soc. Am.1995,97 (4):2255-2262.
[27]Z. Hu and J. S. Bolton. The measurement of plane-wave reflection coefficient be using two-dimensional spatial transforms. J.Acoust. Soc. Am.1990, Suppl.188,S173.
[28]Bruno Brouard,Denis Lafarge and Jean-Francois Allard. Measurement and prediction of the reflection coefficient of porous layers at oblique incidence and for inhomogeneous waves. J. Acoust. Soc. Am.1996,99 (1):100-106.
[29]何元安,李锐,何柞铺.一种任意入射角反射系数反演技术.声学学报。1996,21(6)：928-934.
[30]J. W.Goodman, Introduction to Fourier Optics (McGraw-Hill, San Fran-cisco,1968),Chap.3.
[31]J. C.Piquette.An extrapolation procedure for transient reflection measurements made on thick acoustical panels composed of lossy dispersive materials. J. Acoust. Soc. Am.1987,81:1246-1258.
[32]J. C. Piquette. The ONION method:a reflection coefficient measurement technique for thick underwater acoustic panels. J. Acoust. Soc. Am.1989,85:1029-1040.
[33]J. C.Piquette. Technique for detecting the presence of finite sample-size effects in transmitted-wave measurements made on multiplayer underwater acoustical panels. J. Acoust. Soc. Am.1991,90:2831-2842.
[34]C. Audoly and C. Giangreco. Improvement of the measurement of the transmission coefficient of panels at normal incidence using surface receivers. J. Acoust.1990, 3:369-379.
[35]T.Thibieroz and C.Giangreco. Impulse acoustical measurements of the transmission coefficient of immersed panels. J.Acoust.1991,4:215-236.
[36]A. L.Van Buren. Near field calibration arrays for acoustical wave field determination. IEEE Trans. Instrum. Meas,1992, IM-41:22-26.
[37]李水,缪荣兴,唐海清,水声材料透声性能测量技术的改进。
[38]A.Parvulescu,C.S.Clay, Reproducibility of signal transmissions in the ocean, Radio Electron. Eng.1965,29:p223-228.
[39]B.Y.Zel'dovich, N.F.Pilipetsky, and V.V.Shkunov, Principle of Phase Conjugation, Springer-Verlag, Berlin,1985.
[40]M.Fink, C. Prada, F. Wu, and D. Cassereau, Self focusing in inhomogeneous media with time reversal acoustic mirrors, Proc. IEEE Ultrasonics Symp.(Montreal), 1989,1:681-686.
[41]Draeger C,Cassereau D,Fink M. Theory of the time-reversal process in solids."J.Acoust.Soc.Amer,1997,102(3):1289-1295.
[42]Draeger C,Cassereau D,Fink M. Acoustic time reversal with mode conversion at a solid-fluid interface. Applied Phys.Lett,1988,72(13):1567-1569.
[43]D.R. Jackson and D.R. Dowling, "Phase conjugation in underwater acoustics", J. Acoust. Soc. Am.,1991,89:171-181.
[44]C. Feuillade and C.S. Clay, Source imaging and side-lobe suppression using tie-domain techniques in a shallow-water waveguide, J. Acoust. Soc. Am, 1992,92:2165-2172.
[45]M.R. Dungan, Predictions of narrow-band acoustic time reversal in the shallow ocean, Ph.D. thesis, The University of Michigan,2000.
[46]S.R. Khosla, Performance analysis of an acoustic time reversal system in dynamic and random oceanic environments, Ph.D. thesis, The University of Michigan,2000.
[47]K.G. Sabra, Broadband performance of time-reversing arrays in shallow water, Ph.D. thesis, The University of Michigan,2003.
[48]P.Roux, B.Roman, M.Fink, Time-reversal in an ultrasonic waveguide, Appl.Phys. Lett,1997,70:1811-1813.
[49]Kuperman W A,Hodgkiss W S,Song H C,Akal T,Ferla C,Jackson D R,Phase conjugation in the ocean:Experimental demonstration of an acoustic time-reversal mirror, J.Acoust.Soc.Amer.1998,103(1):25-40.
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