Research on the Layout Optimization of Acoustic Radiation Power Flow Reinforcement Based on Weight-Guide method
Time: 2:40 pm
Author: Qiang Li
Abstract ID: 1035
In order to reduce the noise radiation of the plate and shell structure, the Weight-Guide method is used to optimize the layout of stiffeners for acoustic radiation power flow. Firstly, Rayleigh integral method and Helmholtz equation are used to derive the acoustic radiation power flow, and the sensitivity is calculated by using explicit approximation technique, which takes the acoustic power flow as the objective function. Secondly, the guide weight method is used to update the design variables to optimize the layout of stiffeners and change the shape of the vibration structure, so as to transform the structure into a weak radiator to reduce the radiated sound power. Finally, the optimized structure can optimize the frequency of the partial frequency band reduction by the analysis of numerical examples, and at the same time, the full band optimization of the sound power spectrum can be achieved by changing the number and position of the peaks. Research on the Layout Optimization of Acoustic Radiation Power Flow Reinforcement Based on Weight-Guide method Xiaoyan Teng Harbin Engineering University Laboratory 2035, Building 61,Harbin Engineering University, Heilongjiang Province, China Qiang Li Harbin Engineering University Laboratory 2035, Building 61, Harbin Engineering University, Heilongjiang Province, China Xudong Jiang Harbin University of Science and Technology, Heilongjiang Province, China Zhihua Yan Harbin Engineering University Laboratory 2035, Building 61, Harbin Engineering University, Heilongjiang Province, China In order to reduce the noise radiation of the plate and shell structure,the Weight-Guide method is used to optimize the layout of stiffeners for acoustic radiation power flow.Firstly,Rayleigh integral method and Helmholtz equation are used to derive the acoustic radiation power flow,and the sensitivity is calculated by using explicit approximation technique, which takes the acoustic power flow as the objective function.Secondly, the guide weight method is used to update the design variables to optimize the layout of stiffeners and change the shape of the vibration structure, so as to transform the structure into a weak radiator to reduce the radiated sound power.Finally, the optimized structure can optimize the frequency of the partial frequency band reduction by the analysis of numerical examples, and at the same time, the full band optimization of the sound power spectrum can be achieved by changing the number and position of the peaks. Weight-Guide method; ;
Research on Optimization method of power flow of cylindrical shell stiffener based on BESO
Time: 6:00 am
Author: zhihua yan
Abstract ID: 1037
Research on Optimization method of power flow of cylindrical shell stiffener based on BESO Xiaoyan Teng Harbin Engineering University Laboratory 2035, Building 61,Harbin Engineering University, Heilongjiang Province, China Zhihua Yan Harbin Engineering University Laboratory 2035, Building 61, Harbin Engineering University, Heilongjiang Province, China Xudong Jiang Harbin University of Science and Technology, Heilongjiang Province, China Qiang Li Harbin Engineering University Laboratory 2035, Building 61, Harbin Engineering University, Heilongjiang Province, China In order to establish a method for topological optimization of the power flow response of a cylindrical shell stiffener structure based on BESO, this paper will combine the BESO topology optimization theoretical and the power flow response theory , and take the overall minimization of the power flow of the cylindrical shell stiffener structure as the optimization goal. Then an iterative optimization algorithm for the layout of the stiffener structure on the cylindrical shell surface can be established. The plate-beam coupling structure is used to simulate the cylindrical shell stiffener structure, a finite element model of the cylindrical shell stiffened is established and solved to obtain the power flow sensitivity of the finite element. This is used as an iterative criterion for the layout of the stiffener on the surface of the cylindrical shell structure optimize. Through the analysis of numerical examples, it is obtained that the optimization of the rib layout can better reduce the overall power flow response of the structure, which also verifies the feasibility of the optimization method. power flow; BESO;Inter-Noise2021_Abstract yan
Distortion measurements of sound pressure level generated by a pistonphone
Time: 6:40 am
Author: Thiago Milhomem
Abstract ID: 1136
A supplementary interlaboratory comparison on pistonphone calibration was performed between 2018 and 2020 under the auspices of the Inter-American Metrology System. Seven national metrology institutes took part in this comparison. One pistonphone was circulated among the participants for measurement of the generated sound pressure level, frequency, total distortion + noise and total harmonic distortion. This paper presents the results of distortion measurements and analyzes them. From the stability check, notable variances with respect to reported measurement uncertainty were observed. From reported results, a large difference between the estimated uncertainties by the participants was noted. Convergence between results was found when measurements were performed using one-inch microphone while some divergence between results was found when measurements were performed using half-inch microphone. In addition, these results (using one-inch and half-inch microphones), even when obtained by the same institute, sometimes were different. Reasons for these findings are discussed and suggestions for future comparisons are presented.
A two-zone sound field reproduction based on the region energy control
Time: 6:20 am
Author: Bokai Du
Abstract ID: 1442
Multizone sound field reproduction aims to create different acoustical environments in regions without physical isolation. For a real reproduction system, it is always expected to improve system performance and reduce measurement effort. In this paper, a two-zone sound field reproduction is investigated with a proposed region control method. Conventional multipoint method only controls sound field at limited number of measurement points. However, the proposed method tries to control the sound field energy over the whole region. Considering the systems diverse work environment, different interpolation methods are applied in the proposed method. Simulations are conducted under free field and reverberation condition in order to deeply compare with conventional method and another harmonic domain method. Simulation results show that the proposed method achieves better performance than the conventional multipoint method in free field and reverberant environment. On the other hand, the region control method proposed in this paper is free from microphone array geometry requirement, which means the method is more convenient for the practical application.
Deep Learning-based Health Indicator for Better Bearing RUL Prediction
Time: 6:20 am
Author: Taewan Kim
Abstract ID: 1492
The prognostic performance of data-driven approaches closely depends on the features extracted from the measurement. For a high level of prognostic performance, features must be carefully designed to represent the machines health state well and are generally obtained by signal processing techniques. These features are themselves used as health indicators (HI) or used to construct HIs. However, many conventional HIs are heavily relying on the type of machine components and expert domain knowledge. To solve these drawbacks, we propose a fully data-driven method, that is, the adversarial autoencoder-based health indicator (AAE-HI) for remaining useful life (RUL) prediction. Accelerated degradation tests of bearings collected from PRONOSTIA were used to validate the proposed AAE-HI method. It is shown that our proposed AAE-HI can autonomously find monotonicity and trendability of features, which will capture the degradation progression from the measurement. Therefore, the performance of AAE-HI in RUL prediction is promising compared with other conventional HIs.
Visualization of magnetic field corresponding to acoustic signal and estimation of magnetic source based on symmetry of magnetic field distribution
Time: 7:20 am
Author: Takuto Kurosawa
Abstract ID: 1580
A magnetic field corresponding to an acoustic signal is generated from an antenna, and by using a coil, can be again converted to an acoustic signal. It is possible to estimate where the invisible antenna is with the distribution of the received signal. The estimation is applied to a maintenance of a gas pipe on the situation that the distance from the entrance to a maintenance area is known, but piping route isn't. It is possible to identify maintenance areas of a gas pipe by inserting the antenna to it. The estimation has been done by listening to the received signal manually. However, it is difficult for people to identify accurate point because the difference in the volume for each places is subtle. To solve this problem, we visualized the distribution of the received signal, and estimated the magnetic field with only the acoustic signal. Then, we proposed a method to calculate where the invisible antenna is automatically by using symmetry of the distribution of the received signal.
Sound field reconstruction in rooms with deep generative models
Time: 6:00 am
Author: Xenofon Karakonstantis
Abstract ID: 1864
The characterization of Room Impulse Responses (RIR) over an extended region in a room by means of measurements requires dense spatial with many microphones. This can often become intractable and time consuming in practice. Well established reconstruction methods such as plane wave regression show that the sound field in a room can be reconstructed from sparsely distributed measurements. However, these reconstructions usually rely on assuming physical sparsity (i.e. few waves compose the sound field) or trait in the measured sound field, making the models less generalizable and problem specific. In this paper we introduce a method to reconstruct a sound field in an enclosure with the use of a Generative Adversarial Network (GAN), which s new variants of the data distributions that it is trained upon. The goal of the proposed GAN model is to estimate the underlying distribution of plane waves in any source free region, and map these distributions from a stochastic, latent representation. A GAN is trained on a large number of synthesized sound fields represented by a random wave field and then tested on both simulated and real data sets, of lightly damped and reverberant rooms.
Determination of tonal signal parameters based on zero crossing detection
Time: 3:00 pm
Author: Michal Luczynski
Abstract ID: 1950
This paper presents a method for identifying tonal signal parameters using zero crossing detection. The signal parameters: frequency, amplitude and phase can change slowly in time. The described method allows to obtain accurate detection using possibly small number of signal samples. The detection algorithm consists of the following steps: frequency filtering, zero crossing detection and parameter reading. Filtering of the input signal is aimed at obtaining a signal consisting of a single tonal component. Zero crossing detection allows the elimination of multiple random zero crossings, which do not occur in a pure sine wave signal. The frequency is based on the frequency of transitions through zero, the amplitude is the largest value of the signal in the analysed time interval, and the initial phase is derived from the moment at which the transition through zero occurs. The obtained parameters were used to synthesise a compensation signal in an active tonal component reduction algorithm. The results of the algorithm confirmed the high efficiency of the method.
Experimental sound power from curved plates using the radiation resistance matrix and a scanning vibrometer
Time: 11:40 am
Author: Trent Bates
Abstract ID: 2221
Vibration-based sound power (VBSP) methods based on elemental radiators and measurements from a scanning vibrometer have been shown to be accurate for flat plates and cylinders. In this paper, the VBSP method is extended to account for simple curved structures, with a constant radius of curvature. Data are also presented that suggest the VBSP method is more accurate than the ISO 3741 standard for measuring sound power when significant background noise is present. Experimental results from ISO 3741 and the VBSP methods are compared for three simple curved plate structures with different radii of curvature. The results show good agreement for all three structures over a wide frequency range. The experimental results also indicate that the VBSP method is more accurate in the low frequency range where the curved plates radiated relatively little and significant background noise was present.
Influence of the Bolt Size on the Source of Damping in Automotive Joints
Time: 7:20 am
Author: Shaan Sanjeev
Abstract ID: 2403
Experimental work carried out on automotive bolted joints to investigate the modal damping and energy dissipation capacity in jointed structures in a certain range of frequency are detailed in this paper. Single-lap bolted joints are assembled from aluminium beams, and five different bolt sizes are used to explore the contribution of bolt size have in dissipating energy in engineering structures. An analogous monolithic solid piece beam is sculpted from the same aluminium material to isolate the joint effects and directly compare the structural and joint damping data acquired for the bolted single-lap joints. The common modes of the jointed structures and analogous monolithic beam captured under free-free boundary conditions due to forced excitation are analysed to recognize the contribution and primary source of damping in the same sampling frequency range. The detailed research results of the experimental modal analysis on jointed structures are used to create a simplified but precise analytical model that can be used at a preliminary design stage to estimate the modal behaviour of the jointed structure and the energy loss due to dynamic loading for specific modes of vibration.
Novel features for the detection of bearing faults in railway vehicles
Time: 7:00 am
Author: Matthias Kreuzer
Abstract ID: 2537
In this paper, we address the challenging problem of detecting bearing faults from vibration signals. For this, several time- and frequency domain features have been proposed. However, these proposed features are usually evaluated on data originating from relatively simple scenarios and a significant performance loss can be observed if more realistic scenarios are considered. To overcome this, we introduce Mel Frequency Cepstral Coefficients (MFCCs) and features extracted from the Amplitude Modulation Spetrogram (AMS) as features for the detection of bearing faults. Both AMS and MFCCs were originally introduced in the context of audio signal processing but it is demonstrated that a significantly improved classification performance can be obtained using the proposed features. Furthermore, the data imbalance problem that is prevailing in the context of bearing fault detection, meaning that typically much more data from healthy bearings than from damaged bearings is available. Therefore, we propose to train a One-class SVM with data from healthy bearings only. Bearing faults are then classified by the detection of outliers. Our approach is evaluated with data measured in a highly challenging scenario comprising a state-of-the-art commuter railway engine which is supplied by an industrial power converter and attached to a gear and load.
MEMS digital microphone and Arduino compatible microcontroller: an embedded system for noise monitoring
Time: 7:00 am
Author: Felipe Ramos de Mello
Abstract ID: 2557
Noise assessment and monitoring are essential parts of an acoustician's work since it helps to understand the environment and propose better solutions for noise control and urban noise management. Traditionally, equipment to carry out this task is standardized, and, eventually, expensive for the early career professional. This work develops a high-quality (and cost-effective) prototype for an embedded noise monitoring device based upon a digital I2S MEMS microphone and an Arduino compatible microcontroller, named Teensy. Its small size and low power consumption are also advantages designed for the project. The system captures and processes sound in real-time, computes A and C frequency-weighted equivalent sound levels, along with time-weighted instant levels with a logging interval of 125 ms. Part of the software handles the audio environment, while the biquadratic IIR filters present in the Cortex Microcontroller library are responsible for the frequency- and time-weightings using floating-point for enhanced precision. The prototype results were compared against a Class 2 Sound Level Meter, rendering very similar results for the tested situations, proving a powerful and reliable tool. Improvements and further testing are also being conducted to refine its functioning and characterization. Ultimately, the prototype achieved promising performance, confirming as a solution for noise monitoring.
A study of the effects of structural delamination location on delamination detection using a non-linear chaotic oscillator method
Time: 6:20 am
Author: Xuan LI
Abstract ID: 2804
This work aims to investigate the effects of structural delamination location on the effectiveness of delamination assessment using a vibration-based non-linear chaotic oscillator method. The change in structural vibration characteristics due to delamination at different structural locations can pose a challenge for accurate delamination detection due to the possible weak changes in the measured vibration signal and the existence of noise that can corrupt the signal. Thus in this work, a chaotic oscillator method was used due to its sensitivity to relatively small changes in measured vibration signal and robustness to measurement noise. The effects of vibration sensing location on the sensitivity in detecting the location of delamination was also investigated in this work. The Lyapunov Exponent was used in conjunction with the chaotic oscillator as a damage index, for the purpose of defining an effective measure to locate the delamination damage in a laminated structure. The correlation between the damage index and vibration sensing location for different delamination locations was investigated for a laminated beam structure, with a method for finding an optimal location for vibration sensors proposed. It was found that a vibration sensor placed in selected structural regions can provide an increased level of sensitivity in detecting certain delamination locations. The results from this work also demonstrated the effectiveness of the developed method in determining an optimal placement for vibration sensors for delamination detection.
Assessment of delamination location in composite laminates based on a chaotic oscillator method
Time: 6:40 am
Author: Xuan LI
Abstract ID: 2806
The work aims to study the assessment of delamination location in composite laminates using vibration measurement with a chaotic oscillator method. Delamination is a type of damage that commonly occurs in composite laminates, which can cause a severe degradation of their material properties. The traditional vibration-based methods can encounter difficulties in detecting and locating these delamination-type damages especially when the size of delamination is relatively small and there is a significant level of noise in its vibration measurement. With this particular consideration, a vibration-based method using a non-linear chaotic oscillator was used in this study due to its sensitivity to the change in vibration signal characteristics. A numerical model of composite laminates with delamination damage under harmonic excitation was developed and the vibration signal obtained from composite laminates was processed using the chaotic oscillator method. A feature named Lyapunov Exponent (LE) was used as a delamination damage index to describe the characteristics of the chaotic oscillator for cases with delamination at varying structural locations. The effects of delamination locations on the developed damage index were analyzed in this work. The results showed that there was a strong correlation between the delamination location and the LE feature, even for the case with a relatively high level of measurement noise. The results demonstrated the effectiveness of the method to identify delamination in composite laminates, which has also the potential to be used to detect other types of damages.
High-frequency acoustic impedance tube based on MEMS microphones
Time: 12:00 pm
Author: Roman Schlieper
Abstract ID: 2810
Acoustic impedance tubes are commonly used to measure a test specimen's acoustic characteristics, such as reflection factor, absorption coefficient, or acoustic impedance, in combination with one or two condenser measurement microphones according to associated standards. In the development process of an impedance tube, the microphone diaphragm's size has an important role in the measurement quality. On the one hand, the microphone diameter has to be large enough to ensure the possibility of measuring at low sound pressure levels (SPLs), but on the other hand, the size of the microphone diaphragm should be small in order not to influence the sound propagation through the impedance tube due to the microphone coupling. Micro-Electro-Mechanical Systems (MEMS) microphones are recently widely applied in various acoustic applications due to their small size and high sensitivity. This paper proposes the development of an acoustic impedance tube equipped with 16 MEMS microphones and an inner diameter of 8 mm with an operating frequency range between 60 Hz and 16 kHz. The bottom port MEMS microphones are connected via a 1 mm hole to the tube. The system evaluation is based on standard test specimens like empty probe adapters, rigid termination, and porous absorbers.
Sound power and sound energy measurements using an ellipsoidal measurement surface
Time: 3:20 pm
Author: Edward Zechmann
Abstract ID: 2246
To support purchasing low noise products, sound power and sound energy measurements of sufficient quality need to be routinely made by consumers on a global scale. Sound power measurements using ISO 3744, 3745, and 3746 are conducted in a free field using an acoustic far-field approximation of the intensity integrated over an enveloping measurement surface. Sound power and sound energy measurements generally use a hemispherical, parallelepiped, or cylindrical measurement surface. Those measurement surfaces have limitations and assume that the measurement points lie on the measurement surface often in preferred positions. An alternative approach is to choose microphone positions that optimally satisfy the assumptions of the measurement. The measurement surface should then be fit to the chosen microphone positions. Regression methodologies are available for fitting ellipsoids. The number of microphone positions can be as few as three to fit an ellipsoid. An ellipsoidal measurement surfaces can abut zero, one, two, or three orthogonal reflecting planes. Correction equations for the microphone locations and the angle errors for the microphone orientation and wave propagation direction are shown. This paper will present simulations of sound power, sound energy, and corrections for environmental reflections for ISO 3745 and other measurement surfaces.
Deconvoluting acoustic beamforming maps with a deep neural network
Time: 7:40 am
Author: Wagner Goncalves Pinto
Abstract ID: 3084
Localization and quantification of noise sources is an important scientific and industrial problem, the use of phased arrays of microphones being the standard techniques in many applications. Non-physical artifacts appears on the output due to the nature of the method, thus, a supplementary step known as deconvolution is often performed. The use of data-driven machine learning can be a candidate to solve such problem. Neural networks can be extremely advantageous since no hypothesis concerning the environment or the characteristics of the sources are necessary, different from classical deconvolution techniques. Information on the acoustic propagation is implicitly extracted from pairs of source-output maps. On this work, a convolutional neural network is trained to deconvolute the beamforming map obtained from synthetic data simulating the response of an array of microphones. Quality of the estimation and the computational cost are compared to those of classical deconvolution methods (DAMAS, CLEAN-SC). Constraints associated with the size of the dataset used for training the neural network are also investigated and presented.
Industrial fan vibration signature characterization
Time: 12:00 pm
Author: Timothy Copeland
Abstract ID: 3181
Technique for measuring and reducing industrial fan vibration and noise is detailed. A method used to characterize the vibration signature for 100% industrial fan systems shipped is described. A fan system consists of motor, propeller and cage. We measure triax accelerometer vibration, microphone (both sound pressure level in dBA and raw signal in Pa) along with the current of three phase power for each fan shipped. Comparisons are done immediately with the ISO 14694:2003 standard and troubleshooting and design changes are implemented if vibration limits are exceeded. The method and results are provided for several cases. Troubleshooting and best practices are described for various designs. A portable system takes measurements in the field which are compared to the factory baseline characterization in real time to solve installation problems.
Learning-based estimation of individual absorption profiles from a single room impulse response with known positions of source, sensor and surfaces
Time: 11:00 am
Author: Stéphane Dilungana
Abstract ID: 3186
In situ estimation of the individual absorption profiles of a room remains a challenging problem in building acoustics. This work is aimed at studying the feasibility of this estimation in a shoebox room of fixed and known geometry, using a room impulse response measured from a source and sensor at fixed and known positions. This problem is tackled using supervised learning. Three neural network architectures are compared. Simulated training and validation sets featuring various types of perturbations (surface diffusion, geometrical errors and additive white Gaussian noise) are generated. An extensive empirical simulated study is carried out to determine the influence of these perturbations on the performances of learned models, and to determine which components of the room impulse response are most useful for absorption coefficients prediction. Trained models are shown to yield errors significantly smaller than those of a naive mean estimator on every simulated datasets, including those featuring realistic perturbation levels. Our study outlines the benefit of using convolutional neural network layers, especially when geometrical errors exist. It also reveals that early acoustic echoes are the most salient feature of room impulse responses for absorption coefficient prediction under a fixed geometry.
Experimental determination of the acoustical effects of face masks on speech effort
Time: 3:40 pm
Author: Noah Schumaker
Abstract ID: 3510
The COVID-19 pandemic has led to a global trend in mask wearing. This study investigates how wearing face masks influence the output levels of the human vocal range. Masks were equipped onto a test fixture to evaluate acoustic insertion loss over whole-octave bands important for vocal transmission. With the exception of face shield, tested masks showed less than 2 dB of insertion loss at frequencies less than 2 kHz and up to 5 dB of attenuation at frequencies above 2 kHz. The face shield showed insertion loss of more than 10 dB in the 4 and 8 kHz octave bands.