聲吶部位水聲場(chǎng)的機(jī)械自噪聲傳播分析
發(fā)布時(shí)間：2018-11-13 08:35
【摘要】：聲吶是利用聲波在水中的傳播特性,對(duì)水中的目標(biāo)進(jìn)行探測(cè)、定位、跟蹤、導(dǎo)航和通訊的一種設(shè)備。它在艦船上起著重要的作用,提高聲吶的探測(cè)能力和艦船自身的隱蔽性,可以有效的避免危險(xiǎn)事故的發(fā)生,增強(qiáng)艦船在海水中的生存能力。國內(nèi)外許多學(xué)者從提高聲吶設(shè)備的探測(cè)能力及隱蔽性方面做了深入的研究。降低聲吶部位的自噪聲是提高聲吶工作性能的關(guān)鍵,通過對(duì)自噪聲影響因素的特性分析,可提出有利的降低自噪聲的方法,從而提高聲吶的工作性能。聲吶腔自噪聲的研究主要是對(duì)水動(dòng)力噪聲、螺旋槳噪聲和機(jī)械噪聲等噪聲分量的研究。水動(dòng)力噪聲是艦船在10節(jié)航速以上時(shí)的主要自噪聲分量；螺旋槳噪聲是艦船在水下的主要噪聲源,它對(duì)聲吶自噪聲強(qiáng)度的影響,隨著航速的5-6次方增大；艦船機(jī)械設(shè)備的振動(dòng)噪聲,在低頻低航速時(shí)是聲吶腔自噪聲的重要分量。本文的主要工作是結(jié)合聲吶腔的結(jié)構(gòu)特點(diǎn)和自噪聲預(yù)報(bào)理論,建立聲吶腔機(jī)械自噪聲傳播特性研究模型,利用模態(tài)分析法對(duì)腔體內(nèi)的機(jī)械噪聲分量進(jìn)行預(yù)測(cè)分析,通過定性的模擬計(jì)算,歸納機(jī)械噪聲對(duì)聲吶自噪聲影響的原因。首先,建立了考慮流固耦合作用的聲吶腔的理論分析模型,利用模態(tài)法對(duì)聲吶腔內(nèi)聲場(chǎng)進(jìn)行理論分析。建立了含彈性邊界流固耦合的方程和不含吸聲邊界的流固耦合模態(tài)方程時(shí)模態(tài)方程,并求得了彈性邊界受到外部激勵(lì)時(shí)的聲場(chǎng)聲壓分布解。其次,以彈性薄板模擬受機(jī)械振動(dòng)影響的聲吶上平臺(tái)壁面,矩形腔模擬聲吶腔。外部激勵(lì)作用在彈性平板上,機(jī)械噪聲通過彈性平板的振動(dòng)傳遞到聲吶腔內(nèi)的聲吶基陣處。以此模型應(yīng)用MATLAB軟件對(duì)矩形腔內(nèi)的噪聲進(jìn)行算例分析,通過改變系統(tǒng)的參數(shù),如內(nèi)部阻尼、腔體尺寸及材質(zhì)、透聲窗尺寸等,研究聲吶腔內(nèi)聲場(chǎng)的變化規(guī)律。為了驗(yàn)算理論模型的正確性,應(yīng)用LMS Virtual.lab聲學(xué)軟件對(duì)矩形腔模型進(jìn)行有限元分析。最后,為了尋找降低聲吶腔內(nèi)自噪聲的方法,提出了夾芯板矩形腔模型。對(duì)夾芯板結(jié)構(gòu)進(jìn)行運(yùn)動(dòng)微分方程的建立及求解。經(jīng)MATLAB仿真分析表明,相同厚度的夾芯板比同厚度的矩形薄板降噪效果好,并且正方形的矩形夾芯板降噪效果優(yōu)于長方形的；當(dāng)板為長方形時(shí),隨著板的尺寸的變大,其降噪效果變好。夾芯板的阻尼和夾芯層的損耗因子對(duì)板的減噪量也產(chǎn)生影響,提高阻尼和增大損耗因子可以降低腔內(nèi)噪聲在共振點(diǎn)附近的突變。本文的研究為尋找聲吶腔內(nèi)機(jī)械自噪聲的降低方法提供參考依據(jù),具有重要的應(yīng)用價(jià)值。
[Abstract]:Sonar is a kind of equipment for detecting, locating, tracking, navigating and communicating targets in water. It plays an important role in the ship, improve the sonar detection ability and the ship's own concealment, can effectively avoid the occurrence of dangerous accidents, enhance the ship's survivability in the sea water. Many scholars at home and abroad have done in-depth research on improving the detection ability and concealment of sonar equipment. Reducing the self-noise in the sonar position is the key to improve the sonar performance. By analyzing the characteristics of the factors affecting the self-noise, a favorable method of reducing the self-noise can be put forward to improve the working performance of sonar. The research of sonar cavity self-noise is mainly about hydrodynamic noise, propeller noise and mechanical noise. The hydrodynamic noise is the main self-noise component of the ship when the speed is above 10 knots, the propeller noise is the main noise source of the ship underwater, and the influence of hydrodynamic noise on the sonar self-noise intensity increases with the increase of the speed of the ship to the 5-6th power. The vibration noise of ship mechanical equipment is an important component of sonar cavity self-noise at low speed and low speed. The main work of this paper is to establish a study model of the self-noise propagation characteristics of sonar cavity machinery based on the structural characteristics of sonar cavity and the theory of self-noise prediction, and to use modal analysis method to predict and analyze the components of mechanical noise in the cavity. Through qualitative simulation, the causes of the influence of mechanical noise on sonar self-noise are summarized. Firstly, the theoretical analysis model of sonar cavity considering fluid-solid coupling is established, and the sound field in sonar cavity is theoretically analyzed by modal method. The equations of fluid-solid coupling with elastic boundary and the modal equation of fluid-solid coupling without sound absorbing boundary are established. The acoustic pressure distribution of sound field is obtained when the elastic boundary is subjected to external excitation. Secondly, elastic thin plates are used to simulate sonar surface on platform wall and rectangular cavity to simulate sonar cavity affected by mechanical vibration. The external excitation acts on the elastic plate and the mechanical noise is transmitted through the vibration of the elastic plate to the sonar array in the sonar cavity. In this model, MATLAB software is used to analyze the noise in rectangular cavity. By changing the parameters of the system, such as internal damping, cavity size and material, window size, etc., the variation of sound field in sonar cavity is studied. In order to verify the correctness of the theoretical model, the finite element analysis of rectangular cavity model is carried out by using LMS Virtual.lab acoustic software. Finally, in order to find a method to reduce the self-noise in sonar cavity, a rectangular cavity model of sandwich panel is proposed. The differential equations of motion for sandwich panels are established and solved. The MATLAB simulation results show that the noise reduction effect of the same thickness sandwich plate is better than that of the rectangular thin plate with the same thickness, and the noise reduction effect of the square rectangular sandwich plate is better than that of the rectangular sandwich plate. When the plate is rectangular, the noise reduction effect becomes better as the size of the plate becomes larger. The damping of sandwich panel and the loss factor of sandwich layer also affect the noise reduction of the plate. Increasing damping and loss factor can reduce the abrupt change of the noise in the cavity near the common vibration point. The research in this paper provides a reference for finding the method of reducing the mechanical self-noise in sonar cavity and has important application value.
【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：U666.7
本文編號(hào)：2328574
[Abstract]:Sonar is a kind of equipment for detecting, locating, tracking, navigating and communicating targets in water. It plays an important role in the ship, improve the sonar detection ability and the ship's own concealment, can effectively avoid the occurrence of dangerous accidents, enhance the ship's survivability in the sea water. Many scholars at home and abroad have done in-depth research on improving the detection ability and concealment of sonar equipment. Reducing the self-noise in the sonar position is the key to improve the sonar performance. By analyzing the characteristics of the factors affecting the self-noise, a favorable method of reducing the self-noise can be put forward to improve the working performance of sonar. The research of sonar cavity self-noise is mainly about hydrodynamic noise, propeller noise and mechanical noise. The hydrodynamic noise is the main self-noise component of the ship when the speed is above 10 knots, the propeller noise is the main noise source of the ship underwater, and the influence of hydrodynamic noise on the sonar self-noise intensity increases with the increase of the speed of the ship to the 5-6th power. The vibration noise of ship mechanical equipment is an important component of sonar cavity self-noise at low speed and low speed. The main work of this paper is to establish a study model of the self-noise propagation characteristics of sonar cavity machinery based on the structural characteristics of sonar cavity and the theory of self-noise prediction, and to use modal analysis method to predict and analyze the components of mechanical noise in the cavity. Through qualitative simulation, the causes of the influence of mechanical noise on sonar self-noise are summarized. Firstly, the theoretical analysis model of sonar cavity considering fluid-solid coupling is established, and the sound field in sonar cavity is theoretically analyzed by modal method. The equations of fluid-solid coupling with elastic boundary and the modal equation of fluid-solid coupling without sound absorbing boundary are established. The acoustic pressure distribution of sound field is obtained when the elastic boundary is subjected to external excitation. Secondly, elastic thin plates are used to simulate sonar surface on platform wall and rectangular cavity to simulate sonar cavity affected by mechanical vibration. The external excitation acts on the elastic plate and the mechanical noise is transmitted through the vibration of the elastic plate to the sonar array in the sonar cavity. In this model, MATLAB software is used to analyze the noise in rectangular cavity. By changing the parameters of the system, such as internal damping, cavity size and material, window size, etc., the variation of sound field in sonar cavity is studied. In order to verify the correctness of the theoretical model, the finite element analysis of rectangular cavity model is carried out by using LMS Virtual.lab acoustic software. Finally, in order to find a method to reduce the self-noise in sonar cavity, a rectangular cavity model of sandwich panel is proposed. The differential equations of motion for sandwich panels are established and solved. The MATLAB simulation results show that the noise reduction effect of the same thickness sandwich plate is better than that of the rectangular thin plate with the same thickness, and the noise reduction effect of the square rectangular sandwich plate is better than that of the rectangular sandwich plate. When the plate is rectangular, the noise reduction effect becomes better as the size of the plate becomes larger. The damping of sandwich panel and the loss factor of sandwich layer also affect the noise reduction of the plate. Increasing damping and loss factor can reduce the abrupt change of the noise in the cavity near the common vibration point. The research in this paper provides a reference for finding the method of reducing the mechanical self-noise in sonar cavity and has important application value.
【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：U666.7
【引證文獻(xiàn)】
相關(guān)會(huì)議論文 前1條
1 張均平;;潛艇聲吶部位自噪聲預(yù)報(bào)方法研究[A];第十屆船舶水下噪聲學(xué)術(shù)討論會(huì)論文集[C];2005年
，本文編號(hào)：2328574
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