Acoustic Resonance Spectroscopy Research Articles

Multimodal analysis of GRC ageing process using nonlinear impact resonance acoustic spectroscopy

Glass fibre Reinforced Cement (GRC) is a composite material composed of Portland cement mortar with low w/c (water/cement) ratio and high proportion of glass fibres. This material suffers from the ageing process by losing its strength with time because of its exposure to severe weather conditions. Ageing process damages the fibre surface and decreases the mechanical properties of the structural components made of this material. It reduces the elastic modulus and toughness of GRC. Fracture toughness is traditionally measured by four point bending tests. In a previous study by the authors it was observed that ageing related deterioration or damage of GRC could be monitored by Non Destructive Testing (NDT) techniques such as Non-linear Impact Resonance Acoustic Spectroscopy (NIRAS) and other ultrasonic techniques. The scope of this paper is to corroborate previous investigations and offer early damage detection capability by generating more experimental data points by optimizing location of the point of strike and thus generating more resonance vibration modes in NIRAS tests.

Preliminary study on short-term sulphate attack evaluation by non-linear impact resonance acoustic spectroscopy technique

The scope of this paper is to study the sulphate attack on concrete with new testing methods based on vibrational spectroscopy with mechanical waves. These are based on Non-linear Impact Resonance Acoustic Spectroscopy (NIRAS) that allows detecting the frequency shift of its resonant modes. Both, signal quality factor and alpha, are measured to monitor the increase of the non-linearity of the material due to the stiffness change on the matrix after being attacked. Different Portland cement matrices were assessed and results between vibrational tests and the traditional expansion ASTM method were compared. Two types of cement with different C3A content were tested for external sulphate attack and one cement with high C3A content with different amount of addition of SO3 on the original mix was tested for internal attack. NIRAS was suitable for monitoring external sulphate attack process. A microstructual analysis was carried out with thermogravimetry (TG), scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques in order to detect harmful products on damaged series.

A portable blood plasma clot micro-elastometry device based on resonant acoustic spectroscopy

A portable blood plasma clot micro-elastometry device based on resonant acoustic spectroscopy

J0420306 音響共鳴現象と超音波パルスエコー法を利用したソフトマテリアルの膜厚と音速の同時計測

We propose a new measurement method for simultaneously measuring thickness and sound velocity for soft materials such as a conductive polymer film and stacked induced pluripotent stem cells (iPS cells). Using the 75 MHz underwater-type ultrasound transducer, simultaneous thickness and sound velocity measurement has been carried out by combining the acoustic resonant spectroscopy and pulse-echo measurement. The advantage of this method is that the thickness can be derived without using the known value of sound velocity. The thickness of the conductive polymer film and the stacked iPS cells on metal substrate are measured at 10.4 μm and 16.0 μm, respectively. The thickness of conductive polymer and the staked iPS cells agrees well with the reference measured by the confocal laser microscope. T These results indicate that the developed measurement method can be one of the potential candidates for the real-time thickness measurement for the soft materials. For future work, the thickness of living iPS cells should be measured in real time. Using this method, we would like to figure out the relationship between the stacked state and the differentiation of iPS cells.

Characterization of Prestressed Concrete Cylinder Pipe by Resonance Acoustic Spectroscopy

AbstractPrestressed concrete cylinder pipe (PCCP) is a composite pipe structure commonly used for high-pressure water transmission. If these pipes deteriorate, they can cause a water main break, which can cause extensive property damage and compromise the potable water system. Accordingly, there has been considerable interest in developing reliable nondestructive evaluation (NDE) techniques capable of identifying damaged pipes prior to rupture. In the current study, a series of finite-element and experimental studies are undertaken to establish the groundwork for an acoustic resonance–based NDE method capable of characterizing the earliest stage of deterioration in PCCP associated with damage to its outermost layer.

Monitoring the thermal oxidation of thin polymer films by means of acoustic resonant spectroscopy

This paper describes the use of acoustic resonant spectroscopy to monitor the thermal oxidation of a thin polymer film. The samples were linear low-density polyethylene films with thicknesses of 11.6 µm. These were heat treated at temperatures ranging from 80 to 100 °C in a furnace with an air ambient for a maximum of 10 h. Although no obvious difference between the optical microscope images of the films with and without heating were found, the sound velocity and density, which were measured using acoustic resonant spectroscopy, clearly changed depending on the heat treatment temperature and time. These changes in the acoustic properties were confirmed to be due to thermal oxidation of the films and to correlate with the growth of the oxide which depends on the temperature and time of the heat treatment.

Experimental study of effects of water–cement ratio and curing time on nonlinear resonance of concrete

Experimental techniques based on the theory of nonlinear acoustic resonance have been proved highly sensitive to the development of damage in concrete, particularly during the early age. As a multiphase composite material, the microstructure of concrete has a significant influence on damage development of concrete when subjected to external loading. Hence, it is important to understand the effect of main parameters associated with material microstructure such as water–cement (w/c) ratio and curing period on the nonlinear resonance response of concrete. In this research, theoretical background is first introduced for the implemented nonlinear impact resonance acoustic spectroscopy (NIRAS) technique, in which a parameter representing material nonlinearity is designated as the overall indicator for discontinuous material features of concrete samples. Applying the NIRAS technique, the nonlinearity parameter is analyzed for two sets of concrete samples mixed with different w/c ratios and cured for 7 and 28 days, respectively. The results show that under the increased loading, the longer curing time generally reduces the nonlinear response of concrete because the late filling effect of hydrated products in voids of interfacial transition zone could limit the development of microcracks. The higher w/c ratio will accelerate the nonlinear response of concrete due to the interconnection effect of material porosity on the propagation of microcracks. It is also noteworthy that the nonlinear response of samples in intact state corresponding to a lower w/c ratio is, however, enhanced. This effect is explained by the fact that less capillary water existing in the samples mixed with a lower w/c ratio work as lubricating fluid in voids to mitigate the opening–closing motion of initial material defects.

Numerical experiment and analysis of the differential acoustic resonance spectroscopy for elastic property measurements

Differential acoustic resonance spectroscopy (DARS) was recently developed to estimate the elastic parameters of rock samples with a resonant frequency perturbation caused by a test sample at kilohertz frequency. In the derivation of the DARS theory, the wave inside the cavity is assumed to be a harmonic acoustic plane wave, which may be a source of measurement errors. A simulation program may help researchers to understand the mechanism of this device and to find out whether the assumption in the theory derivation is correct. In this paper, we develop a simulation program based on the elastic wave equation in cylindrical coordinates, and model the DARS system. The modeled power spectrum agrees well with that obtained by the laboratory measurement. An analysis of the wave field snapshots and the pressure distribution curves shows that the standing wave inside the cavity along its long axis is asymmetrical. This study also investigates the relationships between the resonant frequencies and the density, the compressibility and the P-wave and S-wave velocities of the samples. By numerical experiments, this paper finds that only the compressibility can be estimated with the resonant frequency, when the sample is located at the velocity node. But when the sample is located at other positions, the P-wave and S-wave velocities can alter the shape of the vibration curve, though they have no impact on the resonant power spectrum. This implies that it may be possible to estimate the P-wave and S-wave velocities by using the full waveform of the vibration curve.

Acoustic Resonance Spectroscopy for Hazards Materials Classification

In this paper, a measure system based on acoustic resonance is developed for hazards materials classification. It employs the lock-in amplifier as core processor to collect the acoustic resonance spectroscopy (ARS) of sealed containers which storied hazards materials. The transmitter and receiver are coupled externally to the wall of the container. The transmitter generates the sound by using a swept frequency source. The receiver on the opposite side of the wall of the container can detect the transmitted signal. The acoustic properties of hazards materials such as velocity and attenuation can be learned from the observed spectrum signal. Then multivariate methods are used to evaluate pretreatment methods, such as normalization, and classification possibilities of data collected by ARS in a laboratory environment. Principal component analysis (PCA) shows that it is possible to observe differences between samples using the data acquired from the ARS system. Further results obtained from Linear Discriminant Analysis (LDA) show that the identification rates for hazards materials classification are 100%.It is concluded that the ARS system has significant potential in the hazards materials classification.

A proof of principle experiment: Structural transitions in self-healing poly (ethylene co-methacrylic acid) ionomers using acoustic and ultrasonic time dependent resonant spectroscopy

We demonstrate a method for assessing structural transitions in self-healing poly (ethylene co-methacrylic acid) ionomers as a function of time, by observing the evolution of their acoustic and ultrasonic resonant spectra and associated quality factors during the post-damage healing phase. Two samples composed of EMAA-0.6Na and EMAA-0.3Na were scanned from 1 kHz to 2 MHz before and after a damage event. After damage, time varying resonances were discovered using time dependent resonant spectroscopy (TDRS), and several of these resonances continued to evolve after visible changes in the samples ceased. These time dependent resonances enable characterization of energy dissipation, relaxation and structural ordering in self-healing ionomers. In addition, TDRS may provide a method for isolating material properties that affect the healing process, such as ion content and their associated structures as well as the effect of sample aging, which may lead to improved structural models.

Determination of rock acoustic properties at low frequency: A differential acoustical resonance spectroscopy device and its estimation technique

AbstractA laboratory device, Differential Acoustic Resonance Spectroscopy (DARS), has been developed to investigate the acoustic properties of rock materials below 1 KHz. The device is based on analyzing shifts of resonance frequency of a cavity perturbed by the presence of a small sample. Numerical and experimental studies have previously shown that this technique can be used to estimate the compressibility of samples. In this study, we adopt a nonlinear least‐squares whole‐curve‐fitting inversion approach, which for the first time allows estimation of both the compressibility and density of rock samples. In comparison to previous estimation techniques, this inversion method provides more reliable estimation of rock acoustic properties. This research proves that the DARS laboratory device, in conjunction with the calibration technique proposed herein, is a useful tool to estimate the properties of small rock samples. In addition, the simultaneous estimation of compressibility and density can potentially provide information on porosity and, by extension, a link between porosity and acoustic modulus at low frequency.

Nondestructive Monitoring of Ageing of Alkali Resistant Glass Fiber Reinforced Cement (GRC)

Glass fiber reinforced cement (GRC) is a composite material made of portland cement mortar and alkali resistant (AR) fibers. AR fibers are added to portland cement to give the material additional flexural strength and toughness. However, ageing deteriorates the fibers and as a result the improvement in the mechanical properties resulted from the fiber addition disappears as the structure becomes old. The aim of this paper is monitoring GRC ageing by nondestructive evaluation (NDE) techniques. Two different NDE techniques—(1) nonlinear impact resonant acoustic spectroscopy analysis and (2) propagating ultrasonic guided waves—are used for this purpose. Both techniques revealed a reduction of the nonlinear behavior in the GRC material with ageing. Specimens are then loaded to failure to obtain their strength and stiffness. Compared to the un-aged specimens, the aged specimens are found to exhibit more linear behavior, have more stiffness but less toughness. Finally, undisturbed fragments on the fracture surface from mechanical tests are inspected under the electron microscope, to understand the fundamental mechanisms that cause the change in the GRC behavior with ageing.

High Sensitivity Micro-Elastometry: Applications in Blood Coagulopathy

Highly sensitive methods for the assessment of clot structure can aid in our understanding of coagulation disorders and their risk factors. Rapid and simple clot diagnostic systems are also needed for directing treatment in a broad spectrum of cardiovascular diseases. Here we demonstrate a method for micro-elastometry, named resonant acoustic spectroscopy with optical vibrometry (RASOV), which measures the clot elastic modulus (CEM) from the intrinsic resonant frequency of a clot inside a microwell. We observed a high correlation between the CEM of human blood measured by RASOV and a commercial thromboelastograph (TEG), (R=0.966). Unlike TEG, RASOV requires only 150μL of sample and offers improved repeatability. Since CEM is known to primarily depend upon fibrin content and network structure, we investigated the CEM of purified clots formed with varying amounts of fibrinogen and thrombin. We found that RASOV was sensitive to changes of fibrinogen content (0.5-6mg/mL), as well as to the amount of fibrinogen converted to fibrin during clot formation. We then simulated plasma hypercoagulability via hyperfibrinogenemia by spiking whole blood to 150 and 200% of normal fibrinogen levels, and subsequently found that RASOV could detect hyperfibrinogenemia-induced changes in CEM and distinguish these conditions from normal blood.

Characterization of polymer thin coating on substrate by acoustic resonant spectroscopy

A technique for characterizing thin polymer coatings utilizing an acoustic resonant phenomenon is reported. The acoustic properties (acoustic impedance, sound velocity and density) of a coating on a steel plate were determined by observing and analyzing the echo from the back of the plate. Then, acoustic resonant imaging was demonstrated by scanning with a focused ultrasonic transducer. The thickness distribution of the coating on the back of the steel plate was obtained from the acoustic resonant image and the determined velocity of sound in the coating.

Detection of Micro-Bubbles in Thin Polymer Films by Means of Acoustic Resonant Spectroscopy

This paper describes an acoustical method for detecting small scattering sources in thin polymer films with high sensitivity. The technique monitors the acoustic resonance occurring between water, the film and a metallic plate, and an accurate measurement of the ultrasonic attenuation in the film at the resonant frequency is made. Micro-bubbles in the film cause the ultrasonic attenuation in the film to increase.

2E2-2 Monitoring of Thermal Oxidation of Thin Polymer Films by Means of Acoustic Resonant Spectroscopy(Measurement Techniques, Imaging, Nondestructive Evaluation)

2E2-2 Monitoring of Thermal Oxidation of Thin Polymer Films by Means of Acoustic Resonant Spectroscopy(Measurement Techniques, Imaging, Nondestructive Evaluation)

Assessment of alkali–silica reaction damage through quantification of concrete nonlinearity

A newly developed nondestructive evaluation technique, Nonlinear Impact Resonance Acoustic Spectroscopy (NIRAS), is applied to concrete specimens in an ongoing assessment of aggregate alkali reactivity during standard concrete prism testing. NIRAS measures the nonlinearity in a specimen caused by the inception and growth of microcracks throughout the sample and debonding at the aggregate/cement interface. NIRAS is used to exploit the nonlinear effect of excitation amplitude dependent resonance frequency changes, which are related to nonlinearity measurements of concrete samples cast with aggregates of varying reactivity. To relate microstructural changes to changes in nonlinearity and expansion, sample characterization is performed with uranyl-acetate staining. The results demonstrate the utility of NIRAS for not only assessing the potential for ASR under standardized test conditions, but for more general damage characterization in concrete and assessment of “job mixtures.” NIRAS can distinguish reactive from nonreactive aggregates without ambiguity, as supported by sample characterization results.

Acoustic resonance spectroscopy for the advanced undergraduate laboratory

We present a simple experiment that allows advanced undergraduates to learn the principles and applications of spectroscopy. The technique, known as acoustic resonance spectroscopy, is applied to study a vibrating rod. The setup includes electromagnetic-acoustic transducers, an audio amplifier and a vector network analyzer. Typical results of compressional, torsional and bending waves are analyzed and compared with analytical results.

Structural analysis of the (BiScO3)1−x -(PbTiO3) x ceramic materials using the resonance and phonon spectroscopy

The resonance acoustic spectroscopy shows significant structural ordering of the (BiScO3)1 − x -(PbTiO3) x ceramic material in the course of polarization, which leads to an additional increase in the velocity of acoustic waves. The decay rate of acoustic waves increases with increasing frequency and parameter x. The analysis of the ceramic material using the method of thermal pulses at liquidhelium temperatures yields sufficiently high quality of the intergrain boundaries.

Application of resonant acoustic spectroscopy to asphalt concrete beams for determination of the dynamic modulus

In this paper, a new application of resonant acoustic spectroscopy (RAS) is examined for constructing asphalt concrete mastercurves from seismic testing. The frequency-dependent material properties can be characterized from multiple modes of vibration through the use of RAS. Beam-shaped asphalt specimens are tested at multiple temperatures to determine the resonance frequencies of the specimens. The resonance frequencies are estimated by applying a small load impulse and measuring the resulting acceleration through the specimens. Using RAS, the material properties of the specimens are determined numerically using the measured resonance frequencies. The results presented show that the frequency-dependent dynamic modulus of the asphalt concrete specimens can be characterized using several modes of vibration at each testing temperature.