Artigos de revistas: "Acoustic material characterisatio"

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Zhao, Tianfei, Baorui Pan, Xiang Song, Dan Sui, Heye Xiao e Jie Zhou. "Heuristic Approaches Based on Modified Three-Parameter Model for Inverse Acoustic Characterisation of Sintered Metal Fibre Materials". Mathematics 10, n.º 18 (8 de setembro de 2022): 3264. http://dx.doi.org/10.3390/math10183264.

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Modelling of sound propagation in porous media generally requires the knowledge of several transport properties of the materials. In this study, a three-parameter analytical model that links microstructure properties of sintered metal fibre materials and non-acoustical parameters of the JCAL model is used and modified, and two heuristic approaches based on the established model for inverse acoustic characterisation of fibrous metal felts are developed. The geometric microstructure of sintered fibrous metals is simplified to derive the relationship between pores and fibre diameters. The new set of transport parameters in the modified three-parameter model can cover two controllable parameters during the fabrication process of fibrous metals. With two known transport parameters, six sintered specimens are characterised using a deterministic algorithm, and a satisfactory result is achieved in fitting the normalised surface impedance measured by an acoustic measurement system. Moreover, the forward evaluation shows that our modified three-parameter theoretical model is capable of yielding accurate results for the sintered metal fibre materials. A numerical investigation of the complete inverse acoustic characterisation of fibrous metals by a global non-deterministic algorithm indicates that inversion from two porous material properties is preferable to the normalised surface impedance.

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PETTONI POSSENTI, Vincenzo, Emanuele MACCAFERRI, Gioia FUSARO, Luca BARBARESI e Laura MAZZOCCHETTI. "Preliminary investigation of nanofibrous membranes for sound absorption". INTER-NOISE and NOISE-CON Congress and Conference Proceedings 270, n.º 4 (4 de outubro de 2024): 7051–57. http://dx.doi.org/10.3397/in_2024_3903.

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Nanofibrous membranes show interesting mechanical properties, low thickness and lightness, besides the possibility of using a great variety of polymers. The electrospinning technique makes possible the production of polymeric random nanofibres to form nonwoven membranes, which are currently used in several application fields, such as filtration, biomedicine, biomechanics, electronics, and composite materials. Their application in the automotive and aerospace engineering field could bring significant benefits to the acoustic comfort design. However, their acoustics properties still need to be further assessed. This study investigates the acoustic absorption of electrospinning-made nanofibrous membranes in Nylon 66 with different fibre diameters and mat thicknesses. Morphological and thermal characterisation of the electrospun membranes have been assessed via Scanning Electron Microscope (SEM) and Differential Scanning Calorimetry (DSC), respectively. The acoustic absorption characteristics of various samples changing fibre diameter, membrane thickness and mounting conditions were tested in the impedance tube. The results showed more relevant acoustic absorption properties in the nanofibrous membrane coupled with a polyester fibre. Further studies will clarify if filament direction and constituent material can be improved for a more durable and resistant membrane application.

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Tandon, R. P., e Ramadhar Singh. "Development and Characterisation of Composite Hydrophones". Engineering Plastics 2, n.º 5 (janeiro de 1994): 147823919400200. http://dx.doi.org/10.1177/147823919400200502.

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Piezo components have been fabricated using lead zirconate titanate (PZT) and lead titanate (PT) as filler materials in a passive chloroprene rubber matrix. The temperature dependence of the dielectric parameters of PT composites has been studied. Effect of poling temperature and poling field on piezoelectric charge coefficient (d33) has also been examined in order to achieve optimum polarization. Three types of hydrophones were developed using solid PZT, PZT composite and PT composite. Their acoustic sensitivities have been presented over a frequency range 10–100 KHz. The hydrophone based on lead titanate composite exhibited the highest acoustic sensitivity (-202 dB re IV/mPa) which could find numerous applications in underwater acoustics.

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Tandon, R. P., e Ramadhar Singh. "Development and Characterisation of Composite Hydrophones". Polymers and Polymer Composites 2, n.º 5 (janeiro de 1994): 287–92. http://dx.doi.org/10.1177/096739119400200502.

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Piezo components have been fabricated using lead zirconate titanate (PZT) and lead titanate (PT) as filler materials in a passive chloroprene rubber matrix. The temperature dependence of the dielectric parameters of PT composites has been studied. Effect of poling temperature and poling field on piezoelectric charge coefficient (d33) has also been examined in order to achieve optimum polarization. Three types of hydrophones were developed using solid PZT, PZT composite and PT composite. Their acoustic sensitivities have been presented over a frequency range 10–100 KHz. The hydrophone based on lead titanate composite exhibited the highest acoustic sensitivity (-202 dB re IV/mPa) which could find numerous applications in underwater acoustics.

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Nuawi, Mohd Zaki, Abdul Rahim Bahari, Shahrum Abdullah, Ahmad Kamal Ariffin Mohd Ihsan e Fauziana Lamin. "Material Property Characterisation Method Using Vibro-Acoustic Signals". Applied Mechanics and Materials 663 (outubro de 2014): 447–52. http://dx.doi.org/10.4028/www.scientific.net/amm.663.447.

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Material play an important role in engineering design and the characterisation of material property has become an essential requirement for their successful application as structural elements. In this paper, the development of material property characterisation method has been presented. Impulsive excitation test has been performed on rectangular bars (medium carbon steel S50C, cast iron FCD 500, stainless steel AISI 304and brass). The transient vibro-acoustic signals generated during the excitation test have been captured using data acquisition system consist of accelerometer-microphone combination. A new method for reducing the noise components from the recorded signals is introduced by an extensive process of a new Z-stem filtering technique. The filtered signals have been analysed using an alternative statistical method known as Integrated Kurtosis-based Algorithm for Z-notch filter (I-kazTM) to determine the pattern of the signal and to estimate the significance differences among those materials. The representation of the experimental curves obtained by the determination of I-kaz coefficient, Z∞ for various impact forces and materials revealed that the results are statistically significant and can be successfully used for determining the correlation between the curves and material property. Implications of this research to material property characterisation will be discussed.

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Włodarska, Dorota, Andrzej Klepka, Wieslaw Jerzy Staszewski e Tadeusz Uhl. "Comparative Study of Instantaneous Frequency Extraction in Nonlinear Acoustics Used for Structural Damage Detection". Key Engineering Materials 588 (outubro de 2013): 33–42. http://dx.doi.org/10.4028/www.scientific.net/kem.588.33.

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Nonlinear acoustics deals with various nonlinear effects that occur in ultrasonic wave propagation. The method is suitable for material characterisation, as it uses different nonlinear phenomena associated with material imperfections. The method has been used for detecting nonlinearities in cracked solids by: measuring distortions of acoustic signals, estimating resonance frequency shifts or assessing nonlinear vibro-acosutic modulations. The latter is the most widely used non-classical approach to probe material nonlinearities. The method involves vibro-acoustic interactions of ultrasonic wave and modal vibration in damaged specimens. Modulation intensity that strongly relates to damage severity - is usually assessed in the frequency domain and often leads to confusing results when large modulations are involved. The paper investigates the time domain analysis of vibro-acoustic modulated signals. Several methods for instantaneous frequency calculation used to assess the intensity of modulation - are compared. Simulated and experimental data are used in these investigations.

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Wang, Lian, Lian Wang e Victor Humphrey. "The use of a parametric array source and nearfield scanning in the characterisation of panel materials for underwater acoustics". INTER-NOISE and NOISE-CON Congress and Conference Proceedings 265, n.º 1 (1 de fevereiro de 2023): 6403–12. http://dx.doi.org/10.3397/in_2022_0965.

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The properties of the materials used in underwater acoustics are important for applications such as acoustic windows, reflectors and baffles, acoustic barriers or screens, decoupling materials, and anechoic coatings. To characterise the performance of such materials at frequencies above 1 kHz, measurements are typically undertaken on samples of the material in the form of finite sized panels. Such measurements suffer from uncertainty due to the finite size of the panel (leading to contaminating signals from edge diffraction), and the difficulty in simulating the ideal plane-wave insonification. This paper describes work at the UK National Physical Laboratory to minimise these effects by use of: (i) a parametric array as a sound source that provides a directional beam and short broadband pulses; and (ii) nearfield scanning using a hydrophone to sample the complex sound pressure field interacting with the test sample, decomposing the sound field into its plane-wave components. Results are presented of these techniques applied to measurements in laboratory test tanks at frequencies between a few kilohertz and a few hundred kilohertz to determine the reflection and transmission performance of a range of test samples, including panels consisting of homogeneous polymers and materials with regular periodic structure.

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Mao, Huina, Romain Rumpler e Peter Göransson. "An inverse method for design and characterisation of acoustic materials". MATEC Web of Conferences 304 (2019): 02002. http://dx.doi.org/10.1051/matecconf/201930402002.

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This paper presents applications of an inverse method for the design and characterisation of anisotropic elastic material properties of acoustic porous materials. Full field 3D displacements under static surface loads are used as targets in the inverse estimation to fit a material model of an equivalent solid to the measurement data. Test cases of artificial open-cell foams are used, and the accuracy of the results are verified. The method is shown to be able to successfully characterise both isotropic and anisotropic elastic material properties. The paper demonstrates a way to reduce costs by characterising material properties based on the design model without a need for manufacturing and additional experimental tests.

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Claes, Leander, Sarah Johannesmann, Henning Zeipert e Bernd Henning. "Broadband acoustic waves in plate-like structures for acoustic material characterisation". Journal of Physics: Conference Series 2822, n.º 1 (1 de setembro de 2024): 012171. http://dx.doi.org/10.1088/1742-6596/2822/1/012171.

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Abstract Guided acoustic waves can be used for a multitude of different testing and material characterisation purposes. The options for evaluation are especially plentiful if a method for broadband excitation, e.g. thermoelastic excitation using focused, pulsed laser radiation, is used, and if the distance between excitation and detection of the acoustic waves can be varied. In this contribution, methods to infer different quantitative material properties from the recorded spatiotemporal measurement data are presented, ranging from isotropic elastic properties to parameters describing absorption for complex absorption models.

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Ciaburro, Giuseppe, Gino Iannace, Laura Ricciotti, Antonio Apicella, Valeria Perrotta e Raffaella Aversa. "Acoustic Applications of a Foamed Geopolymeric-Architected Metamaterial". Applied Sciences 14, n.º 3 (31 de janeiro de 2024): 1207. http://dx.doi.org/10.3390/app14031207.

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The paper compares and evaluates the influence of the presence of perforations on the sound absorption coefficient (SAC) of a negative stiffness metamaterial based on a foamed ceramic geopolymer. Chemical–physical, microstructural, dynamic–mechanical, and sound characterisations are presented. A rigid, lightweight geopolymeric porous material has been prepared using an inorganic/organic monomeric mixture containing oligomeric sialates and siloxanes foamed with aluminium powder. This process results in an amorphous rigid light foam with an apparent 180 Kg/m3 density and a 78% open-pore. The viscoelastic characterisation by dynamic mechanical analysis (DMA) carried out from 10−3 to 103 Hz indicates the behaviour of a mechanical metamaterial with negative stiffness enabling ultrahigh energy absorption at straining frequencies from 300 to 1000 Hz. The material loss factor (the ratio of dissipative/elastic shear moduli) is about 0.03 (essentially elastic behaviour) for frequencies up to 200 Hz to suddenly increase up to a value of six at 1000 Hz (highly dissipative behaviour). The corresponding storage and loss moduli were 8.2 MPa and 20 MPa, respectively. Impedance tube acoustic absorption measurements on perforated and unperforated specimens highlighted the role of perforation-resonant cavities in enhancing sound absorption efficiency, particularly within the specified frequency band where the mass of the negative stiffness foamed geopolymer matrix magnifies the dissipation effect. In the limits of a still exploratory and comparative study, we aimed to verify the technological transfer potentiality of using architected metamaterials in sustainable building practices.

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Hamadou-Ali, Mohamed, Amar Benazzouk e Haikel Ben Hamed. "Viability of flax particles to develop cellular construction materials: Physico-mechanical characterisation". Journal of Building Materials and Structures 9, n.º 2 (28 de dezembro de 2022): 133–40. http://dx.doi.org/10.34118/jbms.v9i2.2782.

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The problems related to environmental issues have motivated extensive research on environmentally friendly materials. The built environment is responsible for high primary energy use and more of energy related CO2 emissions. However, it is important to develop low-embodied energy, carbon-negative, sustainable construction materials to replace conventional products. In this context, agricultural wastes are the excellent alternative materials to substitute mineral aggregates because they are widespread and easily accessible. The application of these elements is interesting as regards the recycling of the vegetable particles, since these are easily available and renewable low-cost raw materials, and has advantage for economy and environment. However, the reduction of energy consumption in construction, production of thermal insulation materials, and the solution of environmental problems by recycling waste are becoming greater problems. Various types of agriculture waste, after being processed, have been used as particles in concrete or mortars. These materials display lower density and have several potential applications such as acoustic and thermal insulation, fire resistance cladding…etc. The study reported in this paper was undertaken to investigate the physico-mechanical properties of cellular materials based on flax particles, in order to produce usable materials in cellular concrete applications. The material produced containing different volumes of flax particles (0V (control mortar), 1V, and 2V) was lightened by creating a porous structure in the matrix through a chemical reaction between aluminium powder and free lime. A study conducted on hardened material properties has indicated a significant reduction in sample unit weight, thereby resulting in a level of compressive strength compatible with a load-bearing wall. The reduction in flexural strength was lower than that in compressive strength. These results shown that the cellular material based on flax particles can be used as suitable insulated load-bearing walls.

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Nguyen, Vu Hieu, Quoc-Bao Nguyen, Camille Perrot, Agustín Rios de Anda, Estelle Renard e Salah Naili. "Multiscale characterisation of acoustic behaviour of a new bio-based porous material". INTER-NOISE and NOISE-CON Congress and Conference Proceedings 265, n.º 4 (1 de fevereiro de 2023): 3966–71. http://dx.doi.org/10.3397/in_2022_0565.

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This work aims at studying the mechanical and acoustic behaviours of a new bio-based porous epoxy resin obtained by a "green" adapted combination of the cationic photopolymerization and the porogen leaching technique. This new kind of material generally possesses interconnected complex morphology and it would be useful to consider this feature in a model. In this study, the effective properties of the material were estimated by using the asymptotic homogenization method. Four types of ordered pore arrangements together with systematic variations of the porosity and the pore size have been studied. Based on the results of these investigations, a subtle relation between the microstructure and mechanical/acoustic properties has been established. The estimated equivalent dynamic density and equivalent dynamic bulk modulus were compared with experimental results obtained by conducting the three-microphone impedance tube testing. The processing parameters of material elaboration could be adjusted so that the obtained porous material would possess the best sound absorption performance.

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Claes, Leander, Hanna Schmiegel, Clemens Grünsteidl, Sarah Johannesmann, Manuel Webersen e Bernd Henning. "Investigating peculiarities of piezoelectric detection methods for acoustic plate waves in material characterisation applications". tm - Technisches Messen 88, n.º 3 (22 de janeiro de 2021): 147–55. http://dx.doi.org/10.1515/teme-2020-0098.

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Abstract Acoustic waves in plates have proven a viable tool for testing and material characterisation purposes. There are a multitude of options for excitation and detection of theses waves, such as optical and piezoelectric systems. While optical systems, with thermoelastic excitation and interferometric detection, have the benefit of being contactless, they usually require rather complex and expensive experimental setups. Piezoelectric systems are more easily realised but require direct contact with the specimen and usually have a limited bandwidth, especially in case of piezoelectric excitation. In this work, the authors compare the properties of piezoelectric and optical detection methods for broad-band acoustic signals. The shape (e. g. the displacement) of a propagating plate wave is given by its frequency and wave number, allowing to investigate correlations between mode shapes and received signal strengths. This is aided by evaluations in normalised frequency and wavenumber space, facilitating comparisons of different specimens. Further, the authors explore possibilities to utilise the specific properties of the detection methods to determine acoustic material parameters.

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Mat Daud, Anis Nazihah, Md Supar Rohani e Rosly Jaafar. "Acoustic Characterisation of Konjac Glucomannan Gel as a Medical Phantom". Solid State Phenomena 268 (outubro de 2017): 379–83. http://dx.doi.org/10.4028/www.scientific.net/ssp.268.379.

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Acoustic properties are the main criteria to evaluate the compatibility of tested materials as a medical phantom. We determined the acoustic properties of konjac glucomannan (KGM) gel to verify its compatibility as a medical phantom. The acoustic properties measurement employed ultrasonic insertion technique and utilized two identical transducers of 5 MHz center frequencies. One KGM gel block with 5.62 mm thickness was used as sample to determine its longitudinal speed, acoustic impedance and attenuation coefficient at three different water temperatures; (21.5 ± 0.1), (22.5 ± 0.1) and (23.5 ± 0.1) °C. Findings indicated that its longitudinal speed and acoustic impedance increased from (1495 ± 1) to (1499 ± 1) m s-1 and (1.555 ± 0.001) to (1.559 ± 0.001) × 106 kg m-2 s-1 as the water temperature increased from (21.5 ± 0.1) to (23.5 ± 0.1) °C. It also indicated that its attenuation coefficient varied around (0.1303 ± 0.0107) to (0.1373 ± 0.0103) dB cm-1 with increasing water temperature. KGM gel is compatible to be a medical phantom since its acoustic properties are comparable to the acoustic properties of human soft tissue.

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Li, Wenqi, Jethro Coulson, John W. Aveson, Richard J. Smith, Matt Clark, Michael G. Somekh e Steve D. Sharples. "Orientation Characterisation of Aerospace Materials by Spatially Resolved Acoustic Spectroscopy". Journal of Physics: Conference Series 520 (3 de junho de 2014): 012017. http://dx.doi.org/10.1088/1742-6596/520/1/012017.

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Hopper, C., S. Assous, P. B. Wilkinson, D. A. Gunn, P. D. Jackson, J. G. Rees, R. L. O'Leary e M. A. Lovell. "Bioinspired Low-Frequency Material Characterisation". Advances in Acoustics and Vibration 2012 (5 de abril de 2012): 1–12. http://dx.doi.org/10.1155/2012/927903.

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New-coded signals, transmitted by high-sensitivity broadband transducers in the 40–200 kHz range, allow subwavelength material discrimination and thickness determination of polypropylene, polyvinylchloride, and brass samples. Frequency domain spectra enable simultaneous measurement of material properties including longitudinal sound velocity and the attenuation constant as well as thickness measurements. Laboratory test measurements agree well with model results, with sound velocity prediction errors of less than 1%, and thickness discrimination of at least wavelength/15. The resolution of these measurements has only been matched in the past through methods that utilise higher frequencies. The ability to obtain the same resolution using low frequencies has many advantages, particularly when dealing with highly attenuating materials. This approach differs significantly from past biomimetic approaches where actual or simulated animal signals have been used and consequently has the potential for application in a range of fields where both improved penetration and high resolution are required, such as nondestructive testing and evaluation, geophysics, and medical physics.

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Nuawi, Mohd Zaki, Abdul Rahim Bahari, Shahrum Abdullah e Ahmad Kamal Ariffin. "Comparison of Young's Modulus Property Determination of Metallic Materials under Two Statistical Analysis Methods". Advanced Materials Research 894 (fevereiro de 2014): 186–91. http://dx.doi.org/10.4028/www.scientific.net/amr.894.186.

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This paper presents an alternative statistical signal analysis method to characterise and determine Youngs modulus property of metallic materials. For this characterisation purpose, we propose an alternative method called Integrated Kurtosis-based Algorithm for Z-notch filter (I-kazTM) and Mesokurtosis Zonal Nonparametric (M-Z-N). Impulsive excitation test has been performed according to ASTM E1876 on three metallic materials of medium carbon steel S50C, stainless steel AISI 304 and brass to measure the piezoelectric and acoustic signals. The transient acoustic signal has been analysed using M-Z-N analysis while I-kazTM has been used to analyse the impulsive piezoelectric signal. Correlation expression between Youngs modulus property and the calculated statistical parameters has been discussed and the accuracy of these two methods has been identified using cast iron FCD 500 specimen.

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Gaborit, Mathieu, e Luc Jaouen. "Using data-driven techniques to provide feedback during material characterisation". INTER-NOISE and NOISE-CON Congress and Conference Proceedings 265, n.º 5 (1 de fevereiro de 2023): 2305–9. http://dx.doi.org/10.3397/in_2022_0330.

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The aim of the work is to study the feasibility of using machine learning techniques to design a decision helper to assist the characterisation of acoustic materials (porous media for instance). The tool is intended to alert the human operator about specific physical phenomena occurring during the measurements or common mistakes in handling the characterization rig or its parameters. Examples of classical issues include leakage around the samples, unintentional compression during the sample mounting, errors in input parameters such as the static pressure or temperature, etc. The proposed helper relies on a physical analysis and a k-nearest neighbours classifier using the Fréchet distance to score the measurements. This approach allows to measure the similarity between curves, independently from sampling. The training phase is performed on a labelled dataset created from actual impedance tube measurements and possibly some computer generated results to bridge gaps. The inputs are frequency-dependent quantities including normal sound absorption curves, surface impedance, dynamic mass density and dynamic bulk modulus.

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Johannesmann, Sarah, Julia Düchting, Manuel Webersen, Leander Claes e Bernd Henning. "An acoustic waveguide-based approach to the complete characterisation of linear elastic, orthotropic material behaviour". tm - Technisches Messen 85, n.º 7-8 (26 de julho de 2018): 478–86. http://dx.doi.org/10.1515/teme-2017-0132.

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Abstract In this paper, a method for the characterisation of orthotropic, plate-shaped material samples is presented. Ultrasonic plate waves are excited at different angles and then detected. Then, a two-dimensional simulation model can be used to inversely estimate a set of material parameters for each angle of propagation. After merging these individual results into a global set of parameters, the material’s elastic behaviour can be described for arbitrary load directions. The procedure is exemplarily applied to characterise continuous-fibre reinforced polymers.

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Yan, Zhu Ge. "A Review of Aerogels and Their Application as a Multi-functional Building Material". Applied Mechanics and Materials 253-255 (dezembro de 2012): 564–67. http://dx.doi.org/10.4028/www.scientific.net/amm.253-255.564.

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This paper will provide a review of the current research on the material characterisation and mechanical behaviour of polymer enhanced silica aerogels. Aerogels have been in existence for many years; however, the engineering applications of aerogels have been limited due to their poor mechanical behaviour. Recently a new type of polymer enhanced silica aerogel, a nanostructured form of silica has been developed. The new material is having a low density, very low thermal conductivity, excellent acoustic insulation and high mechanical which makes it ideal for energy efficient building material. This paper will discuss the start-of-the-art development of this material and issues to apply the material in energy efficient buildings.

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Egab, Laith, Xu Wang e Mohammad Fard. "Acoustical characterisation of porous sound absorbing materials: a review". International Journal of Vehicle Noise and Vibration 10, n.º 1/2 (2014): 129. http://dx.doi.org/10.1504/ijvnv.2014.059634.

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Dibben, Nicola. "What Do We Hear, When We Hear Music?: Music Perception and Musical Material". Musicae Scientiae 5, n.º 2 (setembro de 2001): 161–94. http://dx.doi.org/10.1177/102986490100500203.

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Theories of auditory event perception have highlighted a distinction between “everyday” and “musical” listening. This paper challenges this account of listening in two ways: first, it extends the notion of source specification to the specification of cultural and compositional categories, and second, it argues that listening to music involves listening to what sounds specify just as much as it involves listening to the acoustic characteristics of sounds. It is argued here that the characterisation of ‘musical’ listening as attending to the acoustic character of sound is a reflection of the prevailing reception ideology of the autonomous art work. This paper reports the results of two empirical studies which provide evidence for the perception of music in terms of categories of musical material (.i.e. what sounds specify). In the first study, participants were presented with triads of musical and everyday sounds presented in conflicting pairings and asked to identify the two that were most similar. In the second study listeners were asked to give commentaries on the sounds. These listening studies showed that while listeners pay attention to the acoustic properties of sounds they are also sensitive to what sounds specify (physical source, physical space and proximity, genre, musical function, performance skill, emotional attributes and social context). The results highlight the way in which listeners privilege particular kinds of specifications, and some of the factors involved in these choices are discussed briefly in relation to a performative theory of musical meaning.

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Solodov, I., K. Pfleiderer, H. Gerhard e G. Busse. "Nonlinear acoustic approach to material characterisation of polymers and composites in tensile tests". Ultrasonics 42, n.º 1-9 (abril de 2004): 1011–15. http://dx.doi.org/10.1016/j.ultras.2003.12.020.

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Brewin, M. P., M. J. Birch, D. J. Mehta, J. W. Reeves, S. Shaw, C. Kruse, J. R. Whiteman et al. "Characterisation of Elastic and Acoustic Properties of an Agar-Based Tissue Mimicking Material". Annals of Biomedical Engineering 43, n.º 10 (14 de março de 2015): 2587–96. http://dx.doi.org/10.1007/s10439-015-1294-7.

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Aoujdad, Khalid, BA Elhadji-Amadou, Pierre Marechal, Damien Leduc, Alexandre Vivet, Florian Gehring e Mounsif ECH-CHERIF El-Kettani. "Integrated analysis of materials for offshore wind turbine blades: mechanical and acoustical coupling". Journal of Physics: Conference Series 2904, n.º 1 (1 de novembro de 2024): 012004. http://dx.doi.org/10.1088/1742-6596/2904/1/012004.

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Abstract This work focuses on assessing the structural degradation of offshore wind turbine blade (OWTB) materials caused by exposure to the marine environment using acoustic and mechanical methods. Samples, consisting of a glass fibre reinforced polymer (GFRP) composite laminate with a styrene-acrylo-nitrile (SAN) foam core, are subjected to an accelerated hygrothermal ageing by immersion in seawater at 28-30% salinity, thermostated at 40°C. Non-destructive characterisation using ultrasonic waves and mechanical testing, including 3- and 4-point bending tests, are carried out. These results are in agreement with mechanical tests which show an 8% reduction in maximum stress for the same immersion time.

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Mohammed, Bizuayehu Y., Chee K. Tan, Steven J. Wilcox e Alex Z. S. Chong. "Damage Characterisation of Carbon Fibre Reinforced Composite Plate Using Acoustic Emission". Key Engineering Materials 558 (junho de 2013): 184–94. http://dx.doi.org/10.4028/www.scientific.net/kem.558.184.

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Acoustic Emission (AE) is a sensitive technique which can be used to characterise damage in high strength composite plate. This paper describes an extension to an earlier piece of research work carried out by the ERC which resulted in the successful development of a novel source location methodology for the said material. The previous work concentrated on the source location in plate-like composite structures using acoustic emission. The work presented in this paper focuses on establishing the correlation between the different damage types suffered in the material namely de-lamination, matrix cracking, fibre rupture and stringer to skin debonding with key signal features of the AE activities. Controlled bending tests were initially carried out on laterally grooved slender composite specimens to progressively propagate damage in the weakened region of these specimens. The composite laminate plate itself is made from 16 plies of carbon fibre twill weaved in an epoxy matrix with bidirectional fibre alignments in the 0° and 90° directions with 60/40 fibre-matrix volume composition. These prepared samples were fully instrumented with broad band (100 kHz to 1MHz) Physical Acoustic AE sensors linked to the necessary signal conditioning hardware. The AE events were recorded using a high speed DAQ card accessed by customised software written in LabVIEWTM. Gathered raw data were analysed off-line for key signal features including energy and frequency contents and subsequently correlated to actual damage types. It can be concluded from the empirical evidence that feature vectors are distinct to the type of damage. Results gathered from additional test on the progressive skin-stringer debonding of the same material to failure confirmed the uniqueness of the AE feature trends. An integrated system which is capable of both in-situ location of compromised sites and the diagnostic of flaw types in composite plate can potentially find engineering applications including the structural health monitoring of composite aircraft parts.

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Alba, Jesús, e Jaime Ramis. "An Alternative Method for the Characterisation of Fibrous Materials from Measurements of Absorption Using Techniques Based on the Allard and Champoux Model". Noise & Vibration Worldwide 31, n.º 8 (setembro de 2000): 19–25. http://dx.doi.org/10.1260/0957456001497968.

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In this work we present a method for characterising fibrous materials from absorption measurements in the Kundt tube. Specific Flow Resistance may be calculated, using techniques based on the Allard & Champoux model. Using this model and taking measurements of absorption as a starting point, the method presented here enables one to achieve a complete characterisation of a fibrous material.

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Brand, Felix, e Klaus Stefan Drese. "Frequency-Resolved High-Frequency Broadband Measurement of Acoustic Longitudinal Waves by Laser-Based Excitation and Detection". Sensors 24, n.º 5 (1 de março de 2024): 1630. http://dx.doi.org/10.3390/s24051630.

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Optoacoustics is a metrology widely used for material characterisation. In this study, a measurement setup for the selective determination of the frequency-resolved phase velocities and attenuations of longitudinal waves over a wide frequency range (3– 55MHz) is presented. The ultrasonic waves in this setup were excited by a pulsed laser within an absorption layer in the thermoelastic regime and directed through a layer of water onto a sample. The acoustic waves were detected using a self-built adaptive interferometer with a photorefractive crystal. The instrument transmits compression waves only, is low-contact, non-destructive, and has a sample-independent excitation. The limitations of the approach were studied both by simulation and experiments to determine how the frequency range and precision can be improved. It was shown that measurements are possible for all investigated materials (silicon, silicone, aluminium, and water) and that the relative error for the phase velocity is less than 0.2 .

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Smith, Elliott, Luzhen Nie, James McLaughlan, Harry Clegg, Thomas Carpenter, David Cowell, Stephen Evans, Alejandro F. Frangi e Steven Freear. "An Open Access Chamber Designed for the Acoustic Characterisation of Microbubbles". Applied Sciences 12, n.º 4 (10 de fevereiro de 2022): 1818. http://dx.doi.org/10.3390/app12041818.

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Microbubbles are used as contrast agents in clinical ultrasound for Left Ventricular Opacification (LVO) and perfusion imaging. They are also the subject of promising research in therapeutics as a drug delivery mechanism or for sonoporation and co-administration. For maximum efficacy in these applications, it is important to understand the acoustic characteristics of the administered microbubbles. Despite this, there is significant variation in the experimental procedures and equipment used to measure the acoustic properties of microbubble populations. A chamber was designed to facilitate acoustic characterisation experiments and was manufactured using additive manufacturing techniques. The design has been released to allow wider uptake in the research community. The efficacy of the chamber for acoustic characterisation has been explored with an experiment to measure the scattering of SonoVue® microbubbles at the fundamental frequency and second harmonic under interrogation from emissions in the frequency range of 1.6 to 6.4 MHz. The highest overall scattering values were measured at 1.6 MHz and decreased as the frequency increased, a result which is in agreement with previously published measurements. Statistical analysis of the acoustic scattering measurements have been performed and a significant difference, at the 5% significance level, was found between the samples containing contrast agent and the control sample containing only deionised water. These findings validate the proposed design for measuring the acoustic scattering characteristics of ultrasound contrast agents.

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Stockburger, Eugen, Hendrik Wester e Bernd-Arno Behrens. "Fracture Characterisation and Modelling of AHSS Using Acoustic Emission Analysis for Deep Drawing". Journal of Manufacturing and Materials Processing 7, n.º 4 (5 de julho de 2023): 127. http://dx.doi.org/10.3390/jmmp7040127.

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Driven by high energy prices, AHSS are still gaining importance in the automotive industry regarding electric vehicles and their battery range. Simulation-based design of forming processes can contribute to exploiting their potential for lightweight design. Fracture models are frequently used to predict the material’s failure and are often parametrised using different tensile tests with optical measurements. Hereby, the fracture is determined by a surface crack. However, for many steels, the fracture initiation already occurs inside the specimen prior to a crack on the surface. This leads to inaccuracies and more imprecise fracture models. Using a method that detects the fracture initiation within the specimen, such as acoustic emission analysis, has a high potential to improve the modelling accuracy. In the presented paper, tests for fracture characterisation with two AHSS were performed for a wide range of stress states and measured with a conventional optical as well as a new acoustical measurement system. The tests were analysed regarding the fracture initiation using both measurement systems. Numerical models of the tests were created, and the EMC fracture model was parametrised based on the two evaluation areas: a surface crack as usual and a fracture from the inside as a novelty. The two fracture models were used in a deep drawing simulation for analysis, comparison and validation with deep drawing experiments. It was shown that the evaluation area for the fracture initiation had a significant impact on the fracture model. Hence, the failure prediction of the EMC fracture model from the acoustic evaluation method showed a higher agreement in the numerical simulations with the experiments than the model from the optical evaluation.

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Alchakra, W., K. Allaf e J. M. Ville. "Acoustical emission technique applied to the characterisation of brittle materials". Applied Acoustics 52, n.º 1 (setembro de 1997): 53–69. http://dx.doi.org/10.1016/s0003-682x(97)00007-8.

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Alba, Jesús, e Jaime Ramis. "The Characterisation of Fibrous Materials from Measurements of Absorption Using Techniques Based on Miki's Model". Noise & Vibration Worldwide 31, n.º 5 (maio de 2000): 14–18. http://dx.doi.org/10.1260/0957456001497607.

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In this work the authors present a method for characterizing fibrous materials from absorption measurements in the Kundt tube. Specific Flow Resistance may be calculated, using techniques based on the Miki's model. Using this model and taking measurements of absorption as a starting point, the method presented here enables one to achieve a complete characterisation of a fibrous material, with the added advantage that no special equipment is needed.

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Sendrowicz, Aleksander, Aleksander Omholt Myhre, Seweryn Witold Wierdak e Alexei Vinogradov. "Challenges and Accomplishments in Mechanical Testing Instrumented by In Situ Techniques: Infrared Thermography, Digital Image Correlation, and Acoustic Emission". Applied Sciences 11, n.º 15 (22 de julho de 2021): 6718. http://dx.doi.org/10.3390/app11156718.

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A current trend in mechanical testing technologies is to equip researchers and industrial practitioners with the facilities for non-destructive characterisation of the deformation and fracture processes occurring on different scales. The synergistic effect of such a combination of destructive and non-destructive techniques both widens and deepens existing knowledge in the field of plasticity and fracture of materials and provides the feedback sought to develop new non-destructive testing approaches and in situ monitoring techniques with enhanced reliability, accuracy and a wider scope of applications. The macroscopic standardised mechanical testing is still dominant in the research laboratories and industrial sector worldwide. The present paper reviews multiple challenges commonly faced by experimentalists, aiming at enhancing the capability of conventional mechanical testing by a combination of contemporary infrared thermography (IRT), rapid video imaging (RVI) with non-contact strain mapping possibilities enabled by the digital image correlation (DIC) method, and the acoustic emission (AE) technique providing unbeatable temporal resolution of the stochastic defect dynamics under load. Practical recommendations to address these challenges are outlined. A versatile experimental setup uniting the unique competencies of all named techniques is described alone with the fascinating possibilities it offers for the comprehensive characterisation of damage accumulation during plastic deformation and fracture of materials. The developed toolbox comprising practical hardware and software solutions brings together measuring technologies, data, and processing in a single place. The proposed methodology focuses on the characterisation of the thermodynamics, kinematics and dynamics of the deformation and fracture processes occurring on different spatial and temporal scales. The capacity of the proposed combination is illustrated using preliminary results on the tensile and fatigue behaviour of the fcc Inconel-625 alloy used as a representative example. Dissipative processes occurring in this alloy are assessed through the complex interplay between the released heat, acoustic emission waves, and expended and stored elastic energy.

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Gong, Hai, Jia Liu, Tao Zhang, Xuan Cao e Long Zhang. "Accuracy improvement of inner defects of cylindrical components using ultrasonic detection with modified ALOK method". Insight - Non-Destructive Testing and Condition Monitoring 66, n.º 3 (1 de março de 2024): 159–66. http://dx.doi.org/10.1784/insi.2024.66.3.159.

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The accuracy of defect localisation and its size quantification is poor in the detection of internal defects of cylindrical components using the ultrasonic Amplituden und Laufzeit Orts-Kurven (ALOK) method. The influence of acoustic beam spread is not taken into consideration in the ultrasonic ALOK method, resulting in difficulties with the precise characterisation of the defect state. To address this, the relationship between the acoustic distance, amplitude, ultrasonic frequency, size and depth of hole defects was studied. The acoustic distance curve and the amplitude curve were fitted and then the localisation model of the defect was obtained. The acoustic beam spreading angle and echo sound pressure were introduced and then the size quantification model for defects was acquired based on principal component analysis (PCA). Both the simulated and experimental results show that the modified ALOK algorithm improved the detection accuracy of the defect location and its size and the relative error of defect sizing decreased by more than 35% compared with the original algorithm.

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Chotard, Thierry, Lizeth Arbelaez Morales, Marie-Laure Bouchetou e Jacques Poirier. "Thermomechanical Characterisation of Mullite Zirconia Composites Sintered from Andalusite for High Temperature Applications". Ceramics 2, n.º 4 (6 de dezembro de 2019): 587–601. http://dx.doi.org/10.3390/ceramics2040046.

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Mullite-Zirconia refractories are well known for their good resistance to corrosion and thermal shock. In this study, several mullite-zirconia composites were developed from andalusite, alumina and zircon sintered at 1600 °C for 10 hours. The samples were subjected to thermal shock carried out after heating at 1200 °C, in order to study the mechanical and thermomechanical behaviour as a function of the amount of zirconia dispersed in the mullite matrix. It appears that that the amorphous phase (SiO2), determined by X-ray diffraction, produced by the decomposition of andalusite, increases considerably with the amount of final zirconia in the composite and has a very important influence on the porosity. This amorphous phase seems also to have an important influence on the mechanical properties of the material. The characterisation of the thermomechanical behaviour (elastic properties and damage monitoring) was carried out thanks to ultrasonic techniques (US echography and Acoustic Emission). The “surprising” evolution (increase) of the Young’s modulus E of the material after being submitted to repeated thermal shocks is highlighted and explained. The acoustic emission technique carried out at high temperature and also coupled to 4-points bending tests (at room temperature) demonstrates its effectiveness for providing a better understanding of the chronology of the involved mechanisms involved at microstructural scale.

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Šafarič, Riko, Lidija Fras Zemljič, Miroslav Novak, Bogdan Dugonik, Božidar Bratina, Nenad Gubeljak, Silvester Bolka e Simona Strnad. "Preparation and Characterisation of Waste Poultry Feathers Composite Fibreboards". Materials 13, n.º 21 (4 de novembro de 2020): 4964. http://dx.doi.org/10.3390/ma13214964.

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The growth of poultry meat production is increasing industrial waste quantities every year. Feathers represent a huge part of the waste, and international directives and restrictions prevent landfilling of such biodegradable materials with high burning values. Furthermore, with their unique properties, poultry waste feathers are already a reliable resource for many byproducts, such as keratin extraction, fibres, hydrogel production, etc., all trying to achieve a high-added value. However, mass reduction of waste feathers into useful applications, such as development of alternative building materials, is also an important aspect. To take advantage of feathers’ thermal insulation capabilities, sound damping, and biodegradability, we worked towards mixing waste feathers with wood residues (wood shavings, dust, and mixed residues) for production of composite fibreboards, comparable to the market’s medium density fibreboards. The emphasis was to evaluate waste poultry feathers as the component of natural insulation composites, along with mixed waste wood residues, to improve their mechanical properties. Various composite fibreboards with different shares of wood and feathers were produced and tested for mechanical, thermal, and acoustic properties, and biodegradability, with comparison to typical particle boards on the market. The addition of waste feather fibres into the fibreboards’ structure improved thermal insulation properties, and the biodegradability of fibreboards, but decreased their bending strength. The sound transition acoustic loss results of the presented combination fibreboards with added feathers improved at mid and high frequencies. Finally, production costs are estimated based on small scale laboratory experiments of feather processing (cleaning and drying), with the assumption of cost reduction in cases of large industrial application.

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Sun, Bo, Chuang Zhang, Suzhen Liu, Liang Jin e Qingxin Yang. "Acoustic Response Characteristics of Lithium Cobaltate/Graphite Battery during Cycling". Journal of The Electrochemical Society 169, n.º 3 (1 de março de 2022): 030511. http://dx.doi.org/10.1149/1945-7111/ac5061.

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Lithium-ion battery (LIB) has become an essential part of various advanced energy storage products due to their excellent performance, but the research on battery degradation is always challenging. The technology of using ultrasound to characterise the state of LIBs has unique advantages compared with other non-destructive testing methods. However, there have only been a few studies on the analysis of battery cycle performance through acoustic response results. In this paper, from the perspective of electrochemical-acoustic field coupling, the ultrasonic count is introduced to characterise the battery state. The acoustic response characteristics of the LIB in the cycling are analysed combined with the conventional acoustic metrics. Based on the continuous fatigue damage model, the acoustic count can infer partial change evolution of the overall effective Young’s modulus of the battery. This study shows that the characterisation of the battery state can provide further thinking for the mechanical evolution of the batteries.

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BéCOT, François-Xavier, Fabien CHEVILLOTTE, François BESSAC e Alain GINESTET. "Characterisation and simulation of a general ventilation filter based on a double porosity approach". INTER-NOISE and NOISE-CON Congress and Conference Proceedings 270, n.º 1 (4 de outubro de 2024): 10113–23. http://dx.doi.org/10.3397/in_2024_4391.

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The air filters installed in ventilation systems are designed for collecting dust and particles. These filters usually consist in folded paper or textile, arranged either as a flat slab or in a V-shape frame. Some of them may also contain activated carbon in order to remove molecular compounds. Experimental results show that they can significantly attenuate the upstream sound sources such as fans or other regenerated noise. Though, these acoustic properties are not strictly speaking designed and often result from the tailored filtering capacities. The present work proposes a three-stage methodology to design and optimize the acoustic performance of these filters. The first stage is the characterization of the intrinsic acoustic parameters of the paper or textile. The second stage consists in the validation of these parameters regarding sound attenuation as measured in impedance tube. This includes analytical and finite element computations to correctly account for the mounting conditions of the specimen in the impedance tube. The final stage consists in predicting the sound attenuation measured on the full-size filter, set in shape using the porous composite material theory. The obtained results provide a satisfactory correspondence allowing for an accurate design at an early stage of the project.

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Prylepa, A., C. Reitböck, M. Cobet, A. Jesacher, X. Jin, R. Adelung, M. Schatzl-Linder et al. "Material characterisation with methods of nonlinear optics". Journal of Physics D: Applied Physics 51, n.º 4 (4 de janeiro de 2018): 043001. http://dx.doi.org/10.1088/1361-6463/aa9df4.

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TRIPATHI, NEETU. "A Review on Auxetic Polymeric Materials: Synthetic Methodology, Characterization and their Applications". Journal of Polymer Materials 40, n.º 3-4 (22 de março de 2024): 227–69. http://dx.doi.org/10.32381/jpm.2023.40.3-4.8.

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Over the last three decades, there has been considerable interest in the captivating mechanical properties displayed by auxetic materials, highlighting the advantages stemming from their distinct negative Poisson's ratio. The negative Poisson's ratio observed in auxetic polymeric materials is a result of the distinctive geometries of their unit cells. These unit cells, encompassing structures such as chiral, re-entrant, and rotating rigid configurations, are carefully engineered to collectively generate the desired auxetic behaviour. This comprehensive review article explores the field of auxetic polymeric materials, offering a detailed exploration of their geometries, fabrication methods, mechanical properties, and characterisation. The diverse applications of these materials in impact/ballistic, acoustic, automotive, biomedical, sports, shape memory, strain sensors, electromagnetic shielding, smart filters, and rehabilitation fields are thoroughly examined. Furthermore, the article emphasises the significance of auxetic behaviour in enhancing mechanical performance while shedding light on the challenges and limitations associated with large-scale fabrication of auxetic materials.

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Scruby, C. B., K. A. Stacey e G. R. Baldwin. "Defect characterisation in three dimensions by acoustic emission". Journal of Physics D: Applied Physics 19, n.º 9 (14 de setembro de 1986): 1597–612. http://dx.doi.org/10.1088/0022-3727/19/9/006.

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Scruby, C. B., G. R. Baldwin e K. A. Stacey. "Characterisation of fatigue crack extension by quantitative acoustic emission". International Journal of Fracture 28, n.º 4 (agosto de 1985): 201–22. http://dx.doi.org/10.1007/bf00035216.

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Buttle, D. J., e C. B. Scruby. "Characterisation of fatigue of aluminium alloys by acoustic emission". NDT & E International 25, n.º 6 (dezembro de 1992): 300. http://dx.doi.org/10.1016/0963-8695(92)90739-4.

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Voltaire, Joakim, Ulla Mattila, Andrew Fogden, Susanna Nieminen e Heidi Reinius. "Acoustic characterisation of film splitting in a HSWO printing nip". Nordic Pulp & Paper Research Journal 22, n.º 4 (1 de dezembro de 2007): 424–31. http://dx.doi.org/10.3183/npprj-2007-22-04-p424-431.

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Thomas, Sadiq, e Evans Chinemezu Ashigwuike. "Defect characterisation in ferromagnetic and non-ferromagnetic aircraft plate materials using an electromagnetic acoustic transducer". International Journal of Microstructure and Materials Properties 9, n.º 3/4/5 (2014): 401. http://dx.doi.org/10.1504/ijmmp.2014.066919.

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Nuawi, M. Z., A. R. Bahari, S. Abdullah, A. K. Ariffin e Z. M. Nopiah. "Time Domain Analysis Method of the Impulse Vibro-acoustic Signal for Fatigue Strength Characterisation of Metallic Material". Procedia Engineering 66 (2013): 539–48. http://dx.doi.org/10.1016/j.proeng.2013.12.106.

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Carboni, M., e A. Bernasconi. "Acoustic emission-based monitoring of fatigue damage in CFRP-CFRP adhesively bonded joints". Insight - Non-Destructive Testing and Condition Monitoring 64, n.º 7 (1 de julho de 2022): 393–97. http://dx.doi.org/10.1784/insi.2022.64.7.393.

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Adhesively bonded joints are being increasingly applied in modern structures. However, manufacturing defects and particularly harsh operative conditions may cause local debonding and catastrophic failures. Structural health monitoring (SHM) and non-destructive testing (NDT) procedures are then needed to evaluate the in-service structural integrity of adhesively bonded joints. In this research, an adhesively bonded single-lap joint, both adherends of which are manufactured using a carbon fibre-reinforced polymer (CFRP) composite, is subjected to constant amplitude fatigue loading. During such a test, the integrity and damage condition of the joint is continuously monitored using acoustic emission (AE), while the test itself is periodically interrupted in order to apply micro-computed tomography (μCT) to the specimen, with the aim of investigating the real features of the developing fatigue damage. The results show that, after suitable elaboration and filtering by means of pattern recognition algorithms, acoustic emission-based monitoring allows for effective identification and characterisation of the development of fatigue damage in adhesively bonded joints.

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Alba, Jesus, Jaime Ramis e Jaime Llinares. "The Characterisation of Fibrous Materials from Measurements of Absorption Using Techniques Based on the Voronina Model". Noise & Vibration Worldwide 31, n.º 3 (março de 2000): 14–19. http://dx.doi.org/10.1260/0957456001497418.

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In this work we present a method for characterising fibrous materials from absorption measurements in the Kundt tube. One may calculate the structural characteristics, the complex propagation constant and the specific impedance of material using techniques based on the Voronina Model. Furthermore, this method allows one to estimate the diameter of a fibre for its use in other models, and does not require any special equipment.

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Trinchi, A., W. Wlodarski, Sandro Santucci, D. Di Claudio, Maurizio Passacantando, C. Cantalini, B. Rout, S. J. Ippolito, K. Kalantar-Zadeh e G. Sberveglieri. "Microstructural Characterisation of RF Magnetron Sputtered ZnO Thin Films on SiC". Solid State Phenomena 99-100 (julho de 2004): 123–26. http://dx.doi.org/10.4028/www.scientific.net/ssp.99-100.123.

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The microstructural characterization of r.f. magnetron sputtered ZnO thin films deposited on 6H-SiC is presented with a comprehensive investigation of their properties as a function of annealing temperature and film thickness. These structures, with some modifications, are utilised as Schottky diode hydrogen gas sensors and Surface Acoustic Wave (SAW) devices.

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Ferreira, D. B. B., R. R. da Silva, J. M. A. Rebello e M. H. S. Siqueira. "Failure mechanism characterisation in composite materials using spectral analysis and the wavelet transform of acoustic emission signals". Insight - Non-Destructive Testing and Condition Monitoring 46, n.º 5 (maio de 2004): 282–89. http://dx.doi.org/10.1784/insi.46.5.282.55560.

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