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Steffen Marburg - One of the best experts on this subject based on the ideXlab platform.

  • characteristic amplitude frequency functions of the Radiated Sound Power
    Journal of the Acoustical Society of America, 2017
    Co-Authors: Matthias Klaerner, Mario Wuehrl, Lothar Kroll, Steffen Marburg
    Abstract:

    The simulation-based design of dynamically loaded and acoustically sensitive components essentially includes the determination of the Radiated Sound Power. Regarding several simplifications different approaches based on the surface velocity can be applied, such as the equivalent Radiated Sound Power (ERP). The required frequency steps of steady state dynamic simulations are determined using efficient modal super imposed models. For single modes of rectangular plates, universal amplitude-frequency functions shall be identified. Considering the damping ratio of the mode, only one resonant frequency step is further needed for the estimation of the Radiated Sound Power in the whole given frequency range. Computationally expensive steady state simulations thus are significantly reduced.

  • fea based methods for optimising structure borne Sound radiation
    Mechanical Systems and Signal Processing, 2017
    Co-Authors: Matthias Klaerner, Mario Wuehrl, Lothar Kroll, Steffen Marburg
    Abstract:

    Abstract Lightweight components are typically stiff and thin-walled and thus tend to have significant Sound radiation. Moreover using fibre reinforced plastics offers a wide range of adjusting the material properties such as stiffness and even damping by manipulating layup, fibre and matrix material or fibre volume content. With numerous free parameters within the composites, there is a need of efficient simulation methods in design and optimisation. In contrast, acoustic measures require complex multi-physical models with fluid–structure interaction and are commonly not implemented in standard FEA software. Different approaches based on the surface velocity of the component fill the gap. Namely, there is the equivalent Radiated Power, assuming a unit radiation efficiency all over the surface and neglecting local effects as an upper bound of structure-borne noise. In addition, the volume velocity provides good results for the lower frequency range with the frequency-dependent radiation efficiency as well as the lumped parameter model predictions being exact for dipole modes, too. Last, the kinetic energy is implicitly given in steady state FEA solutions and thus provides information about the dynamic behaviour without any additional efforts. Possibilities and limits of estimating the Radiated Sound Power by these methods will be shown by numerical studies on a composite component. Moreover, the total Power as an integral over frequency is used to demonstrate the feasibility and accuracy of such optimisation objectives.

  • an adjoint operator approach for sensitivity analysis of Radiated Sound Power in fully coupled structural acoustic systems
    Journal of Computational Acoustics, 2017
    Co-Authors: Leilei Chen, Steffen Marburg, Haibo Chen, Hao Zhang, Hongbo Gao
    Abstract:

    Full interaction between structural and fluid domains must be considered for light structures immersed in heavy fluid (e.g. thin steel shells in water). The structural-acoustic design sensitivity analysis provides information on the effect of the design variable on acoustic performance, which makes it a key step for noise control and structural-acoustic optimization. This study uses the finite element method (FEM) to model the structure domain, while the fast multipole boundary element method (BEM) is applied to the exterior acoustic domain. An adjoint operator approach is developed to calculate the sensitivity of the Radiated Sound Power with respect to the design variables, which can be any structural or fluid parameter (e.g. fluid or structural density, Poisson’s ratio, Young’s modulus, and geometric measures). Numerical examples are presented to demonstrate the validity and efficiency of the proposed algorithm.

  • identification of a set of candidate solutions for optimal positioning of damping layers
    SAE International Journal of Passenger Cars - Electronic and Electrical Systems, 2016
    Co-Authors: Gesche Fender, Steffen Marburg, F Duddeck
    Abstract:

    One method to lower noise in a cabin is to position damping layers on vibrating panels, thereby reducing their Radiated Power. To assess the damping effect, criteria like the ERP (equivalent Radiated Power) are widely employed, which estimate the Radiated Sound Power of a panel without taking into account the actual complex system. Advantageously only a part of the structure has to be modeled, but the optimal solution found on the simplified model then often fails for the complete, coupled system, especially if several variants of a cabin have to be considered. Hence, it is proposed to use the structure-only optimization for identification of a set of candidate solutions for optimal positioning of damping layers. These candidate solutions used as initial designs for the coupled investigations should be well distributed in the design space to avoid being wrongly stuck in an optimum with inferior coupled performance. Evolutionary optimization strategies are especially suited for such a multi-modal optimization to derive a candidate set of local optima. They perform better with a small number of design variables, which is achieved by a special parametrization approach for shape and position of damping layers suggested here. This enables the use of a multi-modal optimization method for the positioning of damping layers, which identifies not only one optimal position, but a set of good candidate solutions (set of local minima) on the coarse structure-only model, which are applied to several cabin variants and may be used as initialization and acceleration of coupled optimization.

  • Supersonic intensity and non-negative intensity for prediction of Radiated Sound.
    The Journal of the Acoustical Society of America, 2016
    Co-Authors: Daipei Liu, Herwig Peters, Steffen Marburg, Nicole Kessissoglou
    Abstract:

    Two numerical methods to identify the surface areas of a vibrating structure that radiate Sound are presented. The supersonic intensity identifies only the supersonic wave components of the Sound field contributing to far-field Radiated Sound. The supersonic intensity is calculated using a two-dimensional convolution between a spatial radiation filter and the Sound field. To compute the spatial radiation filter, the shortest surface distance between two points on the structure is calculated using the geodesic distance method. The non-negative intensity is based on acoustic radiation modes and identifies the Radiated Sound Power from a vibrating structure. Numerical models of a baffled plate, a cylinder and an engine crankcase are presented. The supersonic intensity is shown to be difficult to implement at low frequencies due to the size of the spatial radiation filter and accuracy of the surface distances. A cut-off coefficient associated with the acoustic wavenumber of the spatial radiation filter is used to reduce the aperture error. A comparison of the two intensity-based techniques both in terms of a Sound Power ratio and the modal assurance criterion is introduced to identify the optimal values of the cut-off coefficients that result in better convergence between the intensity techniques.

Junming Zhang - One of the best experts on this subject based on the ideXlab platform.

  • the calculation method and the test for Radiated Sound Power of impulsive noise in a reverberant tank
    DEStech Transactions on Computer Science and Engineering, 2018
    Co-Authors: Y U Xinyue, Rui Tang, Junming Zhang
    Abstract:

    A method for calculating the Radiated Sound Power of impulsive noise in a reverberant acoustic field is proposed in this paper, and the computing results of the time-frequency domain characteristic are verified in the tank at ASTL (Acoustic Science and Technology Laboratory). In the frequency domain analysis, the Power spectrum of the impulsive noise is processed by the Welch way. In the time domain analysis, the total Sound Power of the impulsive noise is calculated by the autocorrelated processing, and by which the Radiated Sound Power is reduced. In order to verify the proposed method, the Radiated Sound Power of the impulsive noise is successfully tested in a reverberant tank. The experiment result shows that the Radiated Sound Power of the 10 kHz CW impulsive noise signals in the testing tank is almost as same as that in the anechoic pool, which the testing deviation is less than 1 dB both in time and frequency domain. The work of this paper provides a useful calculation method for measuring the characteristic of the transient noise in a reverberant tank.

Rui Tang - One of the best experts on this subject based on the ideXlab platform.

  • faster calculation of the low frequency Radiated Sound Power of underwater slender cylindrical shells
    Mathematical Problems in Engineering, 2020
    Co-Authors: Rui Tang, He Tian, Dajing Shang
    Abstract:

    Based on the fact that beam-type modes play the main role in determining the Sound radiation from an underwater thin slender (length-to-radius ratio ) elastic cylindrical shell, an equivalent-beam method is proposed for calculating the low-frequency Radiated Sound Power of underwater thin slender unstiffened and stiffened cylindrical shells. The natural bending frequencies of the cylindrical shell are calculated by analytical and numerical methods and used to solve equivalent Young’s modulus of the equivalent beam. This approach simplifies the vibration problem of the three-dimensional cylindrical shell into that of a two-dimensional beam, which can be used to simplify the calculation process of Radiated Sound Power. Added mass is used to approximate the fluid-structure coupling, further simplifying the calculation process. Calculation examples of underwater simply supported unstiffened and stiffened cylindrical shells verify the proposed method by comparison with analytical and numerical results. Finally, the effects of the size and spacing of the stiffeners on the Sound radiation characteristics of underwater free-free stiffened cylindrical shells are discussed. The proposed method can be extended to the rapid calculation of the Sound radiation characteristics of underwater slender complex cylindrical shells in the low-frequency range.

  • measurement of Radiated Sound Power from a complex underwater Sound source in a non anechoic pool based on spatial averaging
    Journal of Sound and Vibration, 2020
    Co-Authors: Dajing Shang, Rui Tang, Jiapeng Song
    Abstract:

    Abstract The measurement of Radiated Sound Power from a complex underwater Sound source in a non-anechoic pool is investigated, taking account of the facts that a non-anechoic pool does not satisfy the conditions for existence of a diffuse field and that the theory applicable to a reverberation room in the air cannot be used for a non-anechoic pool. Based on normal wave theory, a relationship is derived between the spatial average Sound pressure level in the reverberation control area far from the source and the Sound source radiation Power level. The influence on the measurement results of the number of points (i.e., hydrophones) evenly distributed in the non-anechoic pool over which the spatial average is taken is also investigated. The Radiated Sound Power from a marine propulsion system including a propeller is measured using this technique. Both the theoretical and experimental results show that above the cutoff frequency of the non-anechoic pool, the Radiated Sound Power from a complex underwater Sound source can be measured accurately using the spatial average method. The Radiated Sound Power from a marine propulsion system including a propeller measured by this method differs from that obtained using the enveloping surface method by no more than 2 dB. The accuracy of the proposed method is related to the number of averaging points evenly distributed in the non-anechoic pool: the greater the number of evenly distributed points, the higher is the accuracy, and the Radiated Sound Power measured using 256 points evenly distributed in the non-anechoic pool differs from the free field result by no more than 2 dB.

  • the calculation method and the test for Radiated Sound Power of impulsive noise in a reverberant tank
    DEStech Transactions on Computer Science and Engineering, 2018
    Co-Authors: Y U Xinyue, Rui Tang, Junming Zhang
    Abstract:

    A method for calculating the Radiated Sound Power of impulsive noise in a reverberant acoustic field is proposed in this paper, and the computing results of the time-frequency domain characteristic are verified in the tank at ASTL (Acoustic Science and Technology Laboratory). In the frequency domain analysis, the Power spectrum of the impulsive noise is processed by the Welch way. In the time domain analysis, the total Sound Power of the impulsive noise is calculated by the autocorrelated processing, and by which the Radiated Sound Power is reduced. In order to verify the proposed method, the Radiated Sound Power of the impulsive noise is successfully tested in a reverberant tank. The experiment result shows that the Radiated Sound Power of the 10 kHz CW impulsive noise signals in the testing tank is almost as same as that in the anechoic pool, which the testing deviation is less than 1 dB both in time and frequency domain. The work of this paper provides a useful calculation method for measuring the characteristic of the transient noise in a reverberant tank.

  • the low frequency Sound Power measuring technique for an underwater source in a non anechoic tank
    Measurement Science and Technology, 2018
    Co-Authors: Yiming Zhang, Rui Tang, Dajing Shang
    Abstract:

    In order to determine the Radiated Sound Power of an underwater source below the Schroeder cut-off frequency in a non-anechoic tank, a low-frequency extension measuring technique is proposed. This technique is based on a unique relationship between the transmission characteristics of the enclosed field and those of the free field, which can be obtained as a correction term based on previous measurements of a known simple source. The Radiated Sound Power of an unknown underwater source in the free field can thereby be obtained accurately from measurements in a non-anechoic tank. To verify the validity of the proposed technique, a mathematical model of the enclosed field is established using normal-mode theory, and the relationship between the transmission characteristics of the enclosed and free fields is obtained. The Radiated Sound Power of an underwater transducer source is tested in a glass tank using the proposed low-frequency extension measuring technique. Compared with the free field, the Radiated Sound Power level of the narrowband spectrum deviation is found to be less than 3 dB, and the 1/3 octave spectrum deviation is found to be less than 1 dB. The proposed testing technique can be used not only to extend the low-frequency applications of non-anechoic tanks, but also for measurement of Radiated Sound Power from complicated sources in non-anechoic tanks.

  • the investigation of the method for measuring the low frequency Radiated Sound Power in a reverberation tank
    Journal of the Acoustical Society of America, 2016
    Co-Authors: Yiming Zhang, Rui Tang, Dajing Shang
    Abstract:

    In order to measure the low-frequency Radiated Sound Power of the underwater Sound source in a reverberation tank, the measuring method based on the characteristic acquisition of the testing Sound field is proposed. Based on the normal-mode theory, the spatial averaging properties of the reverberation Sound field with the ideal boundaries is firstly derived, of which the Sound field transfer relationship from the reverberation field to the free field is obtained. In addition, for the purpose of obtaining the characteristic of the testing Sound field with the general boundaries, the numerical method based on the ACTRAN software is utilized. According to obtaining the characteristic of the testing Sound field in advance, the low-frequency Radiated Sound Power can be got by measuring the square pressure in a reverberation tank. The proposed method is checked by the experiment measurement. The test results show that by utilizing the proposed method, the low-frequency Radiated Sound Power of the underwater sou...

Y U Xinyue - One of the best experts on this subject based on the ideXlab platform.

  • the calculation method and the test for Radiated Sound Power of impulsive noise in a reverberant tank
    DEStech Transactions on Computer Science and Engineering, 2018
    Co-Authors: Y U Xinyue, Rui Tang, Junming Zhang
    Abstract:

    A method for calculating the Radiated Sound Power of impulsive noise in a reverberant acoustic field is proposed in this paper, and the computing results of the time-frequency domain characteristic are verified in the tank at ASTL (Acoustic Science and Technology Laboratory). In the frequency domain analysis, the Power spectrum of the impulsive noise is processed by the Welch way. In the time domain analysis, the total Sound Power of the impulsive noise is calculated by the autocorrelated processing, and by which the Radiated Sound Power is reduced. In order to verify the proposed method, the Radiated Sound Power of the impulsive noise is successfully tested in a reverberant tank. The experiment result shows that the Radiated Sound Power of the 10 kHz CW impulsive noise signals in the testing tank is almost as same as that in the anechoic pool, which the testing deviation is less than 1 dB both in time and frequency domain. The work of this paper provides a useful calculation method for measuring the characteristic of the transient noise in a reverberant tank.

Dajing Shang - One of the best experts on this subject based on the ideXlab platform.

  • faster calculation of the low frequency Radiated Sound Power of underwater slender cylindrical shells
    Mathematical Problems in Engineering, 2020
    Co-Authors: Rui Tang, He Tian, Dajing Shang
    Abstract:

    Based on the fact that beam-type modes play the main role in determining the Sound radiation from an underwater thin slender (length-to-radius ratio ) elastic cylindrical shell, an equivalent-beam method is proposed for calculating the low-frequency Radiated Sound Power of underwater thin slender unstiffened and stiffened cylindrical shells. The natural bending frequencies of the cylindrical shell are calculated by analytical and numerical methods and used to solve equivalent Young’s modulus of the equivalent beam. This approach simplifies the vibration problem of the three-dimensional cylindrical shell into that of a two-dimensional beam, which can be used to simplify the calculation process of Radiated Sound Power. Added mass is used to approximate the fluid-structure coupling, further simplifying the calculation process. Calculation examples of underwater simply supported unstiffened and stiffened cylindrical shells verify the proposed method by comparison with analytical and numerical results. Finally, the effects of the size and spacing of the stiffeners on the Sound radiation characteristics of underwater free-free stiffened cylindrical shells are discussed. The proposed method can be extended to the rapid calculation of the Sound radiation characteristics of underwater slender complex cylindrical shells in the low-frequency range.

  • measurement of Radiated Sound Power from a complex underwater Sound source in a non anechoic pool based on spatial averaging
    Journal of Sound and Vibration, 2020
    Co-Authors: Dajing Shang, Rui Tang, Jiapeng Song
    Abstract:

    Abstract The measurement of Radiated Sound Power from a complex underwater Sound source in a non-anechoic pool is investigated, taking account of the facts that a non-anechoic pool does not satisfy the conditions for existence of a diffuse field and that the theory applicable to a reverberation room in the air cannot be used for a non-anechoic pool. Based on normal wave theory, a relationship is derived between the spatial average Sound pressure level in the reverberation control area far from the source and the Sound source radiation Power level. The influence on the measurement results of the number of points (i.e., hydrophones) evenly distributed in the non-anechoic pool over which the spatial average is taken is also investigated. The Radiated Sound Power from a marine propulsion system including a propeller is measured using this technique. Both the theoretical and experimental results show that above the cutoff frequency of the non-anechoic pool, the Radiated Sound Power from a complex underwater Sound source can be measured accurately using the spatial average method. The Radiated Sound Power from a marine propulsion system including a propeller measured by this method differs from that obtained using the enveloping surface method by no more than 2 dB. The accuracy of the proposed method is related to the number of averaging points evenly distributed in the non-anechoic pool: the greater the number of evenly distributed points, the higher is the accuracy, and the Radiated Sound Power measured using 256 points evenly distributed in the non-anechoic pool differs from the free field result by no more than 2 dB.

  • the low frequency Sound Power measuring technique for an underwater source in a non anechoic tank
    Measurement Science and Technology, 2018
    Co-Authors: Yiming Zhang, Rui Tang, Dajing Shang
    Abstract:

    In order to determine the Radiated Sound Power of an underwater source below the Schroeder cut-off frequency in a non-anechoic tank, a low-frequency extension measuring technique is proposed. This technique is based on a unique relationship between the transmission characteristics of the enclosed field and those of the free field, which can be obtained as a correction term based on previous measurements of a known simple source. The Radiated Sound Power of an unknown underwater source in the free field can thereby be obtained accurately from measurements in a non-anechoic tank. To verify the validity of the proposed technique, a mathematical model of the enclosed field is established using normal-mode theory, and the relationship between the transmission characteristics of the enclosed and free fields is obtained. The Radiated Sound Power of an underwater transducer source is tested in a glass tank using the proposed low-frequency extension measuring technique. Compared with the free field, the Radiated Sound Power level of the narrowband spectrum deviation is found to be less than 3 dB, and the 1/3 octave spectrum deviation is found to be less than 1 dB. The proposed testing technique can be used not only to extend the low-frequency applications of non-anechoic tanks, but also for measurement of Radiated Sound Power from complicated sources in non-anechoic tanks.

  • the investigation of the method for measuring the low frequency Radiated Sound Power in a reverberation tank
    Journal of the Acoustical Society of America, 2016
    Co-Authors: Yiming Zhang, Rui Tang, Dajing Shang
    Abstract:

    In order to measure the low-frequency Radiated Sound Power of the underwater Sound source in a reverberation tank, the measuring method based on the characteristic acquisition of the testing Sound field is proposed. Based on the normal-mode theory, the spatial averaging properties of the reverberation Sound field with the ideal boundaries is firstly derived, of which the Sound field transfer relationship from the reverberation field to the free field is obtained. In addition, for the purpose of obtaining the characteristic of the testing Sound field with the general boundaries, the numerical method based on the ACTRAN software is utilized. According to obtaining the characteristic of the testing Sound field in advance, the low-frequency Radiated Sound Power can be got by measuring the square pressure in a reverberation tank. The proposed method is checked by the experiment measurement. The test results show that by utilizing the proposed method, the low-frequency Radiated Sound Power of the underwater sou...