Resonant Ultrasonic Spectroscopy Research Articles

Borides Mn3-x{Rh,Ir}5B2 with Ti3Co5B2-type: X-ray single crystal and TEM data, physical properties

A cursory investigation of the phase relations in the Mn-{Rh,Ir}-B systems prompted for each system a ternary compound, Mn3-x{Rh,Ir}5B2, the crystal structure of them was determined from X-ray single crystal data to be isotypic with the Ti3Co5B2-type (space group P4/mbm, No. 127). In both cases the Mn-site in 2a at the origin of the unit cell exhibits a significant defect (or Mn/B substitution). Transmission electron microscopy studies confirm the absence of a superstructure related to these defects/disorder. The two phases, Mn3-xRh5B2 (x∼0.34) and Mn3-xIr5B2 (x∼0.85) at 950 °C show rather limited homogeneity regions pointing towards higher Mn-contents. Whereas temperature dependent magnetization and specific heat measurements of Mn2.15Ir5B2 do not reveal any indication for a magnetic phase transition in the temperature range from 3 to 300 K, a broad specific heat anomaly at around 200 K and a tilde shape of the temperature dependent magnetization of Mn2.66Rh5B2 appears indicative of an antiferromagnetic phase transition. The latter is also reflected by an anomaly of the electrical resistivity (ρ; 4–300 K) of Mn2.66Rh5B2 which displays a non-monotonous temperature dependence, whereas ρ(T) of Mn2.15Ir5B2 displays a simple metallic-like behavior dominated by scattering from defects. Elastic moduli and Poisson's ratio were determined at room temperature from Resonant Ultrasonic Spectroscopy (RUS) data yielding Young's moduli of E ∼ 170 GPa for Mn2.66Rh5B2 and E ∼ 210 GPa for Mn2.15Ir5B2. Vickers hardness HV is lower for Mn2.66Rh5B2 (HV = 590 ≅ 5.79 GPa) than for Mn2.15Ir5B2 (HV = 655 ≅ 6.42 GPa). The indentation fracture toughness for Mn2.15Ir5B2 was IKC = 0.71 ± 0.5 MPa m1/2.

Ultrasonic assessment of aging in lithium metal pouch cells

Lithium metal anodes are prone to non-uniform lithium plating that can lead to dendrite formation, internal short circuits, and catastrophic ignition. This type of structural defect is not captured by battery management systems, prompting the need to advance nondestructive evaluation (NDE) techniques that are suitable for periodic monitoring of the internal structure. An ultrasonic inspection technique is evaluated here as a means of identifying flaws and irregular lithium plating that can be a precursor to dendrite formation and, ultimately, battery failure.Lithium metal pouch cell batteries were aged through electrochemical cycling at a range of moderate constant-current charging and discharging rates. They were inspected intermittently using a tailored local ultrasonic resonance spectroscopy (LURS) approach that measures the local through-thickness resonances of the battery as an indicator of the underlying structure. LURS results showed clear structural resonances in cells in the range of 3–7 MHz, which shifted significantly to lower frequencies as batteries aged. In addition to point measurements, scanning LURS measurements were implemented to map resonance frequencies over the electrode surface. These resonance maps revealed spatial variations in structure that developed during aging and showed better contrast to structural variation than achieved using conventional amplitude-based c-scans of the specimens.NDE results from pouch cell measurements were compared to a destructive physical analysis of the electrode structures using scanning electron microscopy (SEM). The SEM results showed differences in the end-of-life lithium anode structure at different charge rates. The results of this study show the capability of LURS as a means for identifying changes in battery structures during aging and establish resonance trends that may be applied in future work for prognostic modeling of batteries in service.

Investigation on local monitoring paradigms of in-situ conformally fabricated piezopolymer coating-based array transducers: Ultrasonic bulk waves and local ultrasonic resonances

Realistic structures with complex features have been intricate challenges for structural health monitoring (SHM) with permanently installed transducers. Poor conformability of conventional rigid and brittle piezoceramic wafers is a typical issue of applications on surfaces with complex geometry. Moreover, the accompanied high-stress concentration requires high-sensitivity defect detection which is difficult to achieve with large-area monitoring methods like lamb waves at tens to hundreds kHz. Previously, in-situ conformally fabricated piezopolymer coating-based array transducers (PCATs) have been developed to build large-area, lightweight, flexible, and tunable Lamb wave networks. In this study, two novel local monitoring methods were investigated with PCATs, namely ultrasonic bulk wave array inspection and local ultrasonic resonance spectroscopy. For thick structures, ultrasonic bulk waves were generated and detected by PCATs with broadband operating frequencies (1–10 MHz) and flexible array parameters. Simulation tools and imaging algorithms of array inspection in non-destructive testing (NDT) were well implemented based on the analogous directivity pattern and normal-pressure coupling mechanism. As proof of concept, PCATs were applied on example structures with flat, concave, and convex surfaces for internal defect imaging. For thin-walled and/or multilayer structures, PCATs were used to measure local ultrasonic resonances, comparable to conventional non-contact methods. With negligible influence on local mechanical properties and broadband frequency response, multiple resonance peaks from 0 to 25 MHz were identified as zero group velocity (ZGV) Lamb modes and thickness vibration modes of host structures, which can be used as damage indices for local monitoring of corrosion, delamination, stiffness degradation, etc. Through embracing advanced NDT techniques with PCATs, high-sensitivity and quantitative local monitoring could be achieved with conformal networks, offering the possibility to integrate with large-area monitoring as multi-scale SHM for complex structures.

An improved inversion method for shale elastic parameters measurement based on ultrasonic resonance spectroscopy

The accurate measurement of elastic parameters of shale cores has important guidance for the exploration and development of shale oil and gas. The traditional shale acoustic experiment requires multiple samples from different angles and its preparation process is complex. Resonant Ultrasound Spectroscopy has the advantages of repeatable measurement, high accuracy, and the ability to obtain all elastic parameters from a single small sample. However, the influence of clamping force and measuring angle needs comprehensive analysis to ensure that formant can be measured as many and accurately as possible. This research first conducts sensitivity analysis on the elastic parameters of different shale to guide the experiment. In addition, due to the more complex inversion objective function of the anisotropic shale compared to isotropic samples, the traditional Levenberg–Marquardt method has a strong dependence on the initial value and is prone to falling into local optimal solution. The L-BFGS (limited memory BFGS) method is introduced into the inversion of anisotropic elastic parameters of shale, which can significantly improve the inversion efficiency. Finally, the robustness and reliability of the inversion method are validated through theoretical and experimental measurement results. [Work supported by the National Natural Science Foundation of China (42004117 and 42127807).]

Shear and longitudinal attenuations and quality factors of poly(methyl metacrylate) (PMMA) from 20 kHz to 12 MHz investigation with ultrasonic spectroscopy

PMMA is often considered as a calibration material for experimental benches dedicated to viscoelasticity investigation. Nevertheless, regarding literature, data concerning attenuation coefficients and quality factors are essentially available in the MHz frequency range and results in the low-frequency range are scarce and scattered. In this communication, thanks to the use of high-frequency ultrasonic spectroscopy between 2 and 8 MHz in the range 6 °C − 45 °C, Time-Temperature Superposition principle and Resonant Ultrasonic Spectroscopy (RUS), we show that both longitudinal and shear quality factors of PMMA decrease considerably for low frequencies (<MHz), and that the classically accepted linear laws describing attenuation as a function of frequency are valid only beyond several MHz. This variation is attributed to secondary relaxation processes such as γ relaxation considering the activation energy deduced from experimental data. Power laws are proposed to describe the evolution of quality factors and attenuation coefficients versus frequency in the 20 kHz − 12 MHz range.

Experimental Evaluation Method of Carbonation in Concrete Structure Using Nonlinear Resonant Ultrasonic Spectroscopy

Carbonation is a typical type of concrete deterioration that can cause various physicochemical changes and adversely affects the performance of reinforced concrete structures, particularly in offshore structures. Nonlinear resonant ultrasonic spectroscopy (NRUS), which is a non-destructive test technique, is applied in this study to experimentally evaluate the degree of concrete carbonation without damaging the structure. Nonlinearity parameters of test specimens exposed to accelerated carbonation conditions are measured via NRUS. The measured nonlinearity parameters indicate lower values for longer carbonation durations. This is because internal microcracks are reduced by CaCO&lt;sub&gt;3&lt;/sub&gt;, which is a carbonation product. The consistent trend of the experimental results shows that NRUS can be effectively applied to evaluate concrete carbonation.

Process-Specific Topology Optimization Method Based on Laser-Based Additive Manufacturing of AlSi10Mg Components: Material Characterization and Evaluation

In the laser powder bed fusion process (PBF-LB), components are built up incrementally by locally melting metal powder with a laser beam. This process leads to inhomogeneous material properties of the manufactured components. By integrating these specific material properties into a topology optimization algorithm, product developers can be supported in the early phases of the product development process, such as design finding. For this purpose, a topology optimization method was developed, which takes the inhomogeneous material properties of components fabricated in the PBF-LB process into account. The complex pore architecture in PBF-LB components was studied with micro-computed tomography (µCT). Thereby, three characteristic regions of different porosity were identified and analyzed. The effective stiffness in each of these regions was determined by means of resonant ultrasonic spectroscopy (RUS) as well as finite element analysis. Afterward, the effective stiffness is iteratively considered in the developed topology optimization method. The resulting design proposals of two optimization cases were analyzed and compared to design proposals derived from a standard topology optimization. To evaluate the developed topology optimization method, the derived design proposals were additionally manufactured in the PBF-LB process, and the characteristic pore architecture was analyzed by means of µCT.

Enhancement of elastic properties and surface plasmon resonance with the addition of boron oxide to the ZnO−SiO2 glass system

Glass substrates, with their ultrasonic and enhanced Raman signals, are ever-demanding for medical applications. This paper reports the effect of boron addition to the enhancement of the elastic properties and Raman shifting in the Surface Plasmon Resonance results for the zinc borosilicate glass substrate that can be used for optical biosensor applications. Such glasses were prepared by melt–the quenching method and characterized using a densimeter, X-ray diffraction measurement, Fourier transforms infrared spectroscopy, ultrasonic, and surface plasmon resonance spectroscopy. Results from the current study demonstrated how the composition of the glass influences the physical and elastic moduli of the boron-doped zinc silicate series. The physical characteristics of the zinc silicate glasses were predicted to alter significantly after adding boron as a modifier. The glass density decreased from 3392 to 2983 kg/m3 as the percentage of boron increased from 0.10 to 0.20 wt.%, then increased to 3191 kg/m3 at 0.30 wt.%. The X-ray diffraction and Fourier transforms infrared spectroscopy techniques verified the amorphous glass phase. The ultrasonic method determined the glass's ultrasonic longitudinal and shear velocity at a 5 MHz resounding recurrence at room temperature to study elastic moduli. When boron content is added, the longitudinal, Young, shear, and bulk moduli exhibit a decreasing and increasing trend. As the boron content increases and behaves as a modifier, the number of non-bridging oxygen will increase, which will cause the glass network to expand. In addition, the increase in Eopt occurs from 3.4883 to 3.4331 because the sample has a higher number of non-bridging oxygen. The shift for Otto configuration of the SPR results occurs with the increase of boron concentration. The fabricated glass can potentially be used to construct an integrated silicon-based glass substrate for an optical sensor.

The Thermo-Elastic Properties and Damping of U-6wt%Nb

While thermal expansion data exists for quenched (as well as aged) U-6wt%Nb, there is wide variation in the reported room temperature elastic moduli. To better understand the room temperature elastic behavior and to address the complete absence of data on the temperature dependence of the elastic moduli, room temperature and in-situ elevated temperature resonant ultrasonic spectroscopy (RUS) was performed along with x-ray diffraction (XRD) and dilatometry using a thermomechanical analyzer (TMA). An in-situ small- and wide-angle x-ray scattering (SAXS/WAXS) experiment was performed on a companion sample to help interpret the results. The room temperature polycrystalline dynamic moduli were measured to be E = 95.4 ± 4.5 GPa and G = 35.2 ± 0.2 GPa, respectively. As the temperature is raised, the stiffness slowly decreases, consistent with the empirical rule proposed by Varshni, up to the point of precipitation of the equilibrium α-U phase, which is stiffer than the martensitic phases. Homogenization theory of composites can be used to rationalize the observed response at high temperatures and after high-temperature exposures. Aging of the material at low temperatures (≤200°C) does not affect the linear elastic stiffness, but does impact the damping behavior which can be measured through RUS. This change in damping provides another perspective on the microstructure changes induced by low-temperature aging which also result in significant strengthening.

Impact of microstructure on elastic properties in the alloy Ti-42Al-8.5 Nb

The microstructure of a γ-TiAl alloy containing niobium undergoes continuous transformations during annealing at 550 °C. These take place within the α2-phase of lamellar (α2 +γ) colonies. We have characterized these changes by transmission electron microscopy and made a correlation to the elastic constants determined by resonant ultrasonic spectroscopy during in-situ annealing at the same temperature. The results show a continuous increase of the E-modulus. This can be attributed to elastic strains acting within α2 lamellae as a result of lattice transformations. After 5000 h, a thermodynamic equilibrium was established with equal fractions of α2-phase and O-phase that differ only in lattice symmetry and Nb content. Generally, the presence of O-phase should contribute to lower elastic moduli, however in the present case the evolving microstructural characteristics were responsible for the observed increase in the E-modulus.

Toward In-situ Characterization of Additively Manufactured Parts Using Nonlinear Resonance Ultrasonic Spectroscopy

ABSTRACT In this study, we investigate the feasibility of using nonlinear resonance ultrasound spectroscopy (NRUS) for in-situ monitoring of additively manufactured (AM) parts i.e., while they are still on the build plate. In NRUS, the test specimen is excited around one or more of its resonance frequencies with increasing driving amplitude. The linear shift in resonance frequency with the increasing driving amplitude is a measure of the constituent material’s hysteretic nonlinearity (α), which is itself related to some degree of micro-damage in the test specimens. We conduct NRUS on test specimens glued to a thick plate. The specimens are excited using a piezoelectric transducer (PZT) adhered to the bottom of the plate. We use this setup to measure the hysteretic nonlinearity parameters ( and ) of several cylindrical AM specimens fabricated by laser powder bed fusion technique as well as a few non-AM metallic specimens. The measured nonlinearity parameters for the specimens on the build plate (process monitoring mode) are compared to those measured without the build plate (quality control mode). We observe a systematic decrease in the measured nonlinearity when the specimens are tested on the build plate. An analytical study demonstrates that we measure the weighted average nonlinearity of the specimen and build plate, which itself has a lower nonlinearity. Despite the observed difference, the measured nonlinearity parameters of the specimens with and without the build plate are highly correlated. With further investigations, the proposed test setup can potentially be used for characterization of AM parts in situ.

Contact-less, non-resonant and high-frequency ultrasonic technique: Towards a universal tool for plant leaf study

Plant-based measurements are recognized as key methods to obtain insightful data in the field. In general, they are labor-intensive and expensive. In this context, Non-Contact Resonant Ultrasonic Spectroscopy technique (NC-RUS) emerged as a powerful alternative that enabled plant water status determination in a non-destructive, non-invasive and rapid way. However, NC-RUS is not applicable to all plant species as it depends on the possibility to excite and sense thickness resonances in the leaves. In this work, we propose and test an ultrasonic technique that can be used in all leaves, regardless of the appearance of thickness resonances. This technique is based on the contactless measurement of through transmitted airborne ultrasonic pulses in the leaves at high-frequencies and in the absence of thickness resonances, to obtain the leaf ultrasonic velocity (vair). It benefits from the facts that: i) at sufficiently high frequencies (typically around 1 MHz) all leaves are non-resonant (so the technique can be applied to both resonant and non-resonant leaves), ii) the use of high-frequencies allows a greater time resolution and a further miniaturization, making possible to apply the technique to small and irregular leaves. Three different signal processing techniques were used to determine the time it takes to the ultrasonic pulse to cross the leaves (time-of-flight) from the measured signals. Two of them operate in time domain: cross-correlation, and edge detection, while the third one makes use of the Fast Fourier Transform (FFT) and operates in the frequency domain: phase-slope. If leaf thickness is also measured, ultrasound velocity can then be worked out. As ultrasound velocity is determined by density and elastic modulus, it is then closely related to water content and turgor pressure. Obtained ultrasound velocities were first validated by comparing them with those obtained by well-established and standard ultrasonic methods: water immersion transmission (vwater) and NC-RUS (vres). The conclusions of this comparison permitted us to propose a novel methodology that combines the three signal processing techniques used to improve robustness and accuracy for the measurement of ultrasound velocity in plant leaves. It is of interest to note that a bias towards higher values of vair compared to vres was observed. This behavior is considered the consequence of the different influence of the leaf layered structure in these two measurements, so this feature can be further used for leaf structure analysis.

Influence of fast dynamics effects on resonant ultrasonic vibrations of polycrystalline metal rods

A theoretical model for the formation of ultrasonic signals in metallic microcrystalline rods taking into account the metastable behavior of their defective states is proposed. The influence of metastable states of the defective structure of samples on the features of changes in their resonant frequencies in ultrasonic experiments of fast dynamics is analyzed. The decrease in Young's modulus in such processes is explained. The correspondence between theoretical and experimental data is demonstrated for the example of resonant acoustic vibrations of rods made of aluminum alloy D16. Keywords: nonlinear resonant ultrasonic spectroscopy, defect structure, mechanical stresses, effects of fast and slow dynamics.

Nonlinear Resonant Ultrasonic Spectroscopy (NRUS) for Monitoring Fatigue Crack Growth in Aluminum

ABSTRACT Nonlinear resonant ultrasonic spectroscopy (NRUS) is a resonance-based acoustic testing technique that yields the hysteretic elastic nonlinearity parameter by measuring the resonance frequency shift with increasing driving amplitude. NRUS offers great potential for nondestructive evaluation since it is relatively simple to implement and can detect incipient damage thanks to the high sensitivity of hysteretic nonlinearity parameter to micro-damage. Previous research has shown that NRUS can monitor distributed damage in a wide variety of materials, but the application of NRUS for detection of local defects in metals is less explored. In this study, the feasibility of using NRUS to assess local progressive damage in aluminum is investigated. We use three-point bending fatigue test to initiate a single fatigue crack in a large aluminum specimen. The cyclic loading is interrupted at several stages in order to image the crack using Scanning Electron Microscopy (SEM) and to perform NRUS and other tests. As the crack grows in length, NRUS records a gradual increase in the resonance frequency shift. However, the trend for the amplitude dependency of resonance frequency shift is different from what has been previously reported in materials with distributed damage; the resonance frequency changes are larger at low strain than at high strains. In addition, the utility of multi-modal NRUS for locating the fatigue crack is demonstrated. Finally, we compare the results of NRUS and those from an impact-based NRUS (INRUS) that uses an automated impact hammer as the excitation source in differentiating the fatigue-damaged from the intact specimen. Our findings suggest the potential of NRUS and INRUS in detecting local damage in metals.

Resonant ultrasound spectroscopy of silicon carbide ceramics SiC‒AlN

The paper discusses the possibility of using resonant ultrasonic spectroscopy (RUS) as a source of information for the physics and technology of obtaining silicon carbide ceramics by the example of samples of the composition SiC ‒ 25 % AlN, obtained by the method of spark plasma sintering. The possibility of obtaining a complete set of elastic moduli (EM) of samples with an error of less than 1 % is shown. At the same time, the requirements for surface quality are significantly reduced. The revealed functional relationship between EM and porosity makes it possible to create a non-destructive method of porosity control and calculate the elastic moduli at zero porosity (i. e., the elastic modulus of the ceramic matrix EM0). Comparison of EM0 samples obtained at different parameters of the technological process allows determining their optima values..

Resonance ultrasonic spectroscopy applied to normal and tangential contact modes investigation of a constrained metallic sphere

This article reports on the analysis of the vibration modes (central eigenfrequencies) observed on a dry steel sphere clamped between two planes, under static compression and subjected to an acoustic excitation. The experimental technique is based on the analysis of the ultrasonic resonance spectrum (RUS); compression or transverse excitations are used. Two types of vibrations are observed. The first occurring in the low frequency range corresponds to modes of movement conditioned by the contacts; the second corresponds to the internal, toroidal and spheroidal deformation modes. In this article we limit our research to the modes observed in the low frequency regime and our objective is to study the influence of the static force on the position of the peaks observed in the frequency spectra. In the case of a longitudinal excitation, only one mode is observed; the transverse excitation makes it possible to detect two modes. The experimental results are compared to theoretical calculations based on theoretical models of Hertz and Hertz-Mindlin, on a development of the JKR model based on adhesion due to Van der Waals forces. In this work, the mechanical coefficients are considered to be independent of time and we do not study the phenomena of hysteresis of these coefficients.

Nonlinear resonance ultrasonic spectroscopy (NRUS) for the quality control of additively manufactured samples

Additive manufacturing (AM) is becoming increasingly popular due to its ability to build parts with customer-designed complex geometries. However, the lack of established quality control/assurance practices for the built parts poses a challenge to a wider adoption of additive manufacturing by some industries. In this study, we investigate the utility of nonlinear resonance ultrasonic spectroscopy (NRUS) for predicting the fatigue life of cylindrical Ti–6Al–4V samples manufactured using powder bed fusion on the same build. We use NRUS to measure several linear and nonlinear parameters for the samples before and after hot isostatic pressing (HIPing). The samples are then fatigue tested. We report the correlation between NRUS parameters and fatigue life. Our findings suggest that resonance frequency, quality factor, and the hysteretic nonlinearity of the samples are correlated to their fatigue life. These correlations are promising because the measurements are obtained from distinct samples as opposed to collecting data on the same sample undergoing increasing fatigue cycles. This study suggests that NRUS has the potential to be used as a nondestructive evaluation (NDE) tool for AM part quality control.

Linear and nonlinear resonant ultrasonic techniques applied to assess delayed ettringite formation on concrete samples

This study investigates the application of different ultrasonic Non-Destructive tests to assess Delayed Ettringite Formation, in concrete samples exhibiting low kinetic expansions (and up to 0.21%). Linear and nonlinear Resonant Ultrasonic Spectroscopy and Acoustic Emission tests were used. Scanning Electron Microscopy and optical microscopy observations were conducted at the end of the monitoring tests. The results showed a slight increase of the dynamic modulus and Quality factor while nonlinear hysteretic parameters remained constant over the test duration. Acoustic Emission tests attested the occurrence of events. However, the microscopic observations did not reveal meaningful differences in microcracking extent between the samples.

Dielectric, elastic and piezoelectric properties of single domain Pb(Zn1/3Nb2/3)O3–6.5%PbTiO3 single crystal with 3m symmetry measured using one sample

In order to use finite element simulation to design electromechanical devices, self-consistent full tensor material properties are needed. The IEEE resonance technique usually requires more than 5 different geometry samples to complete the full tensor characterization, but the poling degree will depend on the sample geometry in relaxor-base ferroelectric single crystals. Hence, it is very difficult to obtain self-consistent full tensor properties using multiple samples. In this study, we used only one sample to determine the whole set of materials properties for single domain PZN–6.5%PT single crystals by combining the ultrasonic pulse-echo (UPE) method and the resonance ultrasonic spectroscopy (RUS) for the elastic and piezoelectric coefficients and the impedance analyzer for dielectric measurements. Comparison with other reported results show the advantage of our methodology and such self-consistent date set would facilitate fundamental studies on domain engineering technique as well as device design optimization using finite element software.

Fabrication and characterization of aluminum - magnetic shape memory alloy composites

Smart composites, manufactured with embedded functional materials, hold the potential for a new type of structural health monitoring systems. The work herein focuses on how embedding Ni 43 Co 7 Mn 39 Sn 11 metamagnetic shape memory alloy (MMSMA) sensory particles into pure aluminum matrix modifies the chemical constitution and mechanical properties of both materials. Martensitically transforming particles in pure Al or Al alloys can interact with crack tip stress fields and undergo stress-induced martensitic transformation. This process emits acoustic signals and changes the magnetic state of the particles, which can then be exploited using acoustic monitors and/or magnetic sensors to determine the crack locations. Fabrication of these composites consisted of consolidation of homogeneously mixed powder precursors containing 10 vol% of Ni 43 Co 7 Mn 39 Sn 11 MMSMA particles. Elemental composition, hardness, and elastic modulus of the embedded particles and resulting diffusion region between the particles and the matrix were determined using wavelength dispersive spectrometry and instrumented nanoindentation. Elastic constants of the sintered bulk composites were also experimentally determined using resonant ultrasonic spectroscopy (RUS). Compositional analysis revealed that the diffusion region contained a diverse group of intermetallics. Nanoindentation results demonstrated that the diffusion region exhibits a high hardness value of 10.0 ± 0.3 GPa and an elastic modulus of 163 ± 5 GPa, as compared to the embedded particles having a hardness of 4.5 ± 0.4 GPa, and elastic modulus of 127 ± 6 GPa. Poisson's ratio and the stiffness tensor components (C 11 , C 12 , and C 44 ) were found to be 0.34, 214 GPa, 111 GPa, and 52 GPa, respectively, through RUS. The important material properties determined in the present study, especially the interface properties, can be used to model the composite system to optimize the particle size, distribution, and the size of the interfaces for desired bulk mechanical properties and damage sensing ability.