Acoustic Resonance Method Research Articles

Study of Dissipation Properties and Structure Evolution in Metals with Different Grain Size under HCF and VHCF Loadings

The dissipation properties, evolution of the dilatation and elastic properties in sub-microcrystalline titanium Grade 4 samples loaded in HCF and VHCF regime were investigated. The dissipation properties were studied based on self-heating (Risitano) test. The mechanical properties (elastic modulus, amplitude-independent damping) and dilatation for a set of samples with different degrees of the life time exhaustion were studied based on the acoustic resonance method. The dilatation was studied by the method of hydrostatic weighing. The experimental results show the increasing of energy dissipation in submicrocrystalline titanium and absence the characteristic knee point on the graph of dependence of temperature rise versus stress amplitude for this material in self-heating test. The structural investigation shows the decreasing of elastic properties during fatigue loading and increasing of dilatation.

The study of a defect evolution in iron under fatigue loading in gigacyclic fatigue regime

The work is devoted to the study of the damage accumulation in iron under gigacyclic fatigue (VHCF) regime. The study of the mechanical properties of the samples with different state of life time existing was carried out on the base of the acoustic resonance method. The damage accumulation (porosity of the samples) was studied by the hydrostatic weighing method. The obtained results show the accumulation of porosity in the volume of the sample during fatigue loading and corresponding decrease of the elastic properties. A statistical model of damage accumulation was proposed in order to describe the damage accumulation process. The model describes the influence of the sample surface on the location of fatigue crack initiation

Viscoelastic relaxation in fluids

The shear elasticity of different fluids are studied experimentally at relatively low frequencies of 40 and 74 kHz. The real and imaginary shear moduli of several liquids are measured using the acoustic resonance method. A low-frequency viscoelastic relaxation process is assumed to occur in a fluid with a period of relaxation much longer than the lifetime of the individual fluid particles.

A212 電磁超音波共鳴法シミュレーションの実験的検証(OS2 保全・設備診断技術(3))

The electromagnetic acoustic resonance (EMAR) method provides accurate and stable evaluation of thickness of pipes. Wall thickness measurement depend on such as the shape of the pipe. A simulation is necessary to be more reliable thickness assessment. In considering the simulation, it has a problem. The working principle of electromagnetic acoustic transducer (EMAT) caused by the Lorentz force and magnetostrictive effect. It is a complicated operating principles. In order to develop a simulation of EMAT's operating principle by the Lorentz force. The authors verified and compared with the experimental values the validity of analysis in the existing ultrasound analysis.

금속 재료의 잠닉손상 평가를 위한 비선형 전자기음향공진 기법에 관한 연구

최근 전통적 초음파기법이 탐상할 수 없는 잠닉손상을 평가할 수 있는 잠재적 기술로서 비선형 초음파기법들에 대한 많은 관심이 있다. 비선형 초음파기법중 하나인 공진주파수 변화를 이용하는 기법은 재료의 탄성영역에서의 이력에 근거한 기술이다. 공진주파수의 변화량이 아주 작기 때문에 정교한 공진주파수 측정장치가 필요하다. 본 연구에서는 비선형 전자기음향공진기법을 적용하였다. 비선형 전자기음향공진기법은 비접촉 EMAT 센서를 사용하기 때문에 재료의 주파수 응답에 영향을 최소화할 수 있다. 3점 굽힘 피로시험을 한 알루미늄판 시편에 횡파 EMAT으로 실험을 실시하였다. 전압을 여러 레벨로 인가하며 공진을 발생시켜 잠닉손상측정에 중요한 요인중 하나인 이력 비선형 파라미터 <TEX>${\alpha}$</TEX>를 공진주파수 변화로부터 산출하였다. 비손상시편과 손상시편에서의 측정된 이력 비선형 인자의 값이 서로 차이가 남을 확인하였다. Recently, much attention has been paid to nonlinear ultrasonic technology as a potential tool to assess hidden damages that cannot be detected by conventional ultrasonic testing. One nonlinear ultrasonic technique is measurement of the resonance frequency shift, which is based on the hysteresis of the material elasticity. Sophisticated measurement of resonance frequency is required, because the change in resonance frequency is usually quite small. In this investigation, the nonlinear electromagnetic acoustic resonance (NEMAR) method was employed. The NEMAR method uses noncontact electromagnetic acoustic transducers (EMATs) in order to minimize the effect of the transducer on the frequency response of the object. Aluminum plate specimens that underwent three point bending fatigue were tested with a shear wave EMAT. The hysteretic nonlinear parameter <TEX>${\alpha}$</TEX>, a key indicator of damage, was calculated from the resonance frequency shift at several levels of input voltage. The hysteretic nonlinear parameter of a damaged sample was compared to that of an intact one, showing a difference in the values.

High-temperature elastic anisotropy of B2-type FeAl

The electromagnetic acoustic resonance method was applied to measure the elastic constants ( c 11 , c 12 , and c 44 ) of Fe–40, –43 and –46Al (at.%) single crystals from room temperature to 1173 K. The temperature dependence of the energy factor, K , and the elastic anisotropy factor, A , was obtained. A increased monotonously with increasing temperature and reached ∼7 at ∼1200 K. Therefore, it was confirmed that B2-type FeAl shows an anomalous temperature dependence of elasticity.

Thermal vacancy behavior analysis through thermal expansion, lattice parameter and elastic modulus measurements of B2-type FeAl

Thermal vacancy behavior in B2-type FeAl was analyzed through thermal expansion, lattice parameter, and elastic modulus measurements. High-temperature X-ray diffractometry (HT-XRD) was conducted to determine the lattice parameter at elevated temperatures, and the electromagnetic acoustic resonance method was applied to investigate the temperature dependence of the elastic moduli in B2-type FeAl. Using a series of in situ high-temperature techniques such as HT-XRD and dilatometry, the thermal vacancy concentration at elevated temperatures was estimated from the divergence between the changes in the sample length and the lattice parameter with temperature, giving a vacancy formation enthalpy of ∼0.7 and 0.6eV for Fe–40Al and Fe–43Al (at.%), respectively. The long-range order parameter was found to increase with temperature in a high-temperature range, indicating that the Fe-atom recovery process occurs in this temperature range. The in situ high-temperature measurements suggest that at elevated temperatures, thermal vacancies have no significant influence on the lattice parameter and elastic moduli of B2-type FeAl.

Elastoplastic properties of a low-modulus titanium-based β alloy

The elastoplastic properties (elastic modulus, amplitude-independent damping ratio, microplastic flow stress) of a Ti-26Nb-7Mo-12Zr titanium β alloy are determined using an acoustic resonance method. The effect of the strain during thermomechanical treatment on the structural features of the micro-crystalline alloy and, hence, its elastoplastic properties is analyzed.

2P1-4 Monitoring of Film Growth on Quartz by Acoustic Resonance Method(Poster Session)

2P1-4 Monitoring of Film Growth on Quartz by Acoustic Resonance Method(Poster Session)

J041035 アンテナ発信共振法による高温におけるランガサイトの新たな熱活性型緩和現象の発見([J041-03]超音波計測・解析法の新展開(3))

J041035 アンテナ発信共振法による高温におけるランガサイトの新たな熱活性型緩和現象の発見([J041-03]超音波計測・解析法の新展開(3))

Method for monitoring slow dynamics recovery

Slow Dynamics is a specific material property, which for example is connected to the degree of damage. It is therefore of importance to be able to attain proper measurements of it. Usually it has been monitored by acoustic resonance methods which have very high sensitivity as such. However, because the acoustic wave is acting both as conditioner and as probe, the measurement is affecting the result which leads to a mixing of the fast nonlinear response to the excitation and the slow dynamics material recovery. In this article a method is introduced which, for the first time, removes the fast dynamics from the process and allows the behavior of the slow dynamics to be monitored by itself. The new method has the ability to measure at the shortest possible recovery times, and at very small conditioning strains. For the lowest strains the sound speed increases with strain, while at higher strains a linear decreasing dependence is observed. This is the first method and test that has been able to monitor the true material state recovery process.

Role of Thermal Vacancies on Temperature Dependence of Lattice Parameter and Elastic Moduli in B2-type FeAl

ABSTRACTTemperature dependence of the lattice parameter and elastic moduli in Fe-40 and -43Al (at.%) was investigated by high temperature X-ray diffractometry (XRD) and the Electro-Magnetic Acoustic Resonance (EMAR) method. The thermal vacancy concentration was estimated from the activation enthalpy and entropy data of vacancy formation previously reported for FeAl. It was found that both the lattice parameter and the elastic moduli of FeAl have a linear relationship with temperature even in the temperature range where thermal vacancy concentration rapidly increases (above 400 °C), thus suggesting that newly generated thermal vacancies at elevated temperature do not make significant influence on the lattice parameter and the elastic properties of B2-type FeAl.

Detection of Core Rot Symptom of Japanese Pear (Pyrus pyrifolia cv. Kosui) by a Nondestructive Resonant Method

One of the main factors for the lower rating of Japanese pear (Pyrus pyrifolia, cv. Kosui) is contamination of core-rotten fruit in the market. An acoustic resonance method originally developed to measure firmness of fruit with the second resonant frequency was applied to the detection of core rot fruit. Second and third resonant frequencies of ‘Kosui’ Japanese pear with different degrees of core rot were nondestructively measured by a resonant method. Resonant frequency of fruit was determined by sandwiching fruit between the vibrator and detector of a resonant device. Obtained vibration voltage signals were analyzed by fast Fourier transformation. An infected pear with core rot was artificially prepared with injections of conidia suspension of Phomopsis sp. or Colletotricum sp. into the fruit on the tree. Degree of core rot was estimated by the area of the equatorial plane of cut surface. Fruit with less than 500 Hz second resonant frequency had core rot of more than 5% of fruit volume. Discrimination rate was 96.9%. Second resonant frequency more effectively discriminates infected pears with more than 5% core rot from that with less than 5% than the third resonant frequency.

Low Young’s modulus in Ti–Nb–Ta–Zr–O alloys: Cold working and oxygen effects

The origin of the low Young’s modulus of cold worked Ti–36Nb–2Ta–3Zr– xO mass% polycrystals with a body-centered cubic (β-phase) structure, referred to as gum metal, was investigated with a focus on the roles of oxygen concentration, the electron–atom ( e/ a) ratio, and the cold working process. Analysis of the temperature dependence of the microstructures and elastic properties of single crystals at x = 0.09, 0.36, 0.51% O using transmission electron microscopy and an electromagnetic acoustic resonance method, respectively, revealed that the shear moduli c′ and c 44 of the 0.36 and 0.51% O alloys softened upon cooling near room temperature (RT) and exhibited low values at RT. This was because suppression of the α″ martensitic transformation by oxygen addition led to retention of the low stability single β-phase state at RT. The Hill approximation indicated that the low c′ and c 44 values caused by softening gave rise to the low Young’s modulus, which is common to some Ti–Nb-based alloys with an e/ a ratio of ∼4.24. Analysis of the microstructures and elastic properties of solution-treated and cold worked x = 0.06, 0.30, 0.47% O alloy polycrystals at RT revealed that the Young’s modulus increased upon 90% cold working due to formation of the α″ martensite phase (0.09% O) and ω phase (0.09, 0.30, and 0.47% O) with a high elastic modulus in the β-phase matrix. However, increasing the oxygen concentration suppresses the increase in Young’s modulus because oxygen addition decreases the amount of α″ and ω phases formed while retaining the low stability β phase. Therefore, cold working combined with oxygen addition produces a low Young’s modulus compatible with high strength.

Methods to analyze physico-chemical changes during mango ripening: A multivariate approach

Canonical discriminant analysis (CDA) was used to identify the best method to discriminate between maturity and ripening stages, assessed in terms of dry matter content, firmness, color (peel and flesh), total soluble solids content attributes, before and during ‘Keitt’ mango ripening at 20 °C. Dry matter content was determined by hot-air oven and microwave oven methods. Fruit firmness was determined non-destructively by hand squeezing, with a durometer, using acoustic resonance and low-mass elastic impact methods (AWETA), as well as destructively by the penetrometer. Peel and flesh color were expressed as L*, a*, b*, h 0 and C* values. Total soluble solids content was analyzed from filtered juice from whole fruit tissue and from unfiltered juice squeezed out by hand. Canonical discriminant analysis indicated that the durometer and the penetrometer were better methods to assess firmness than hand firmness, acoustic resonance or impact methods. The best color attributes to follow changes during early stage of ‘Keitt’ mango ripening were a* and b* values of the flesh, whereas b* value of the peel was considered better during later stages of ripening. Results of total soluble solids content in filtered juice from whole fruit tissue were less variable compared to unfiltered juice squeezed out by hand. Dry matter content was better assessed by drying the sample in a microwave oven than in a hot-air oven. A combined CDA including the best methods to assess each ripening attribute, as well as titratable acidity, showed that the best tools to assess changes in fruit during ripening were the penetrometer, followed by flesh a* value and total soluble solids content (from filtered juice from whole fruit).

Influence of surface wettability on the accuracy of measurement of fluid shear modulus

The shear moduli of liquids and their dependence on the degree of purity of the piezocrystal surface are measured by acoustic resonance method using a piezoelectric quartz resonator. As a criterion of surface condition the coefficient of static friction is accepted, which is measured by tribometer of Derjaguin–Lazarev design. The various methods of surface treatment which give a wide range of friction coefficients are used. At the maximum value of the coefficient of friction vibrating piezoquartz surface is completely wetted by the liquid and the effective value of the shear modulus of the liquid is the highest.

Low-Frequency Shear Parameters Viscoelastic Relaxation Process

An experimental study of the shear parameters of viscoelastic liquids is carried out by the acoustic resonance method based on the changes in the natural frequency and Q factor of a piezoelectric quartz resonator. The liquid to be studied is placed between a stationary quartz strap and the piezoelectric quartz crystal vibrating at the resonance frequency. For a set of drilling mud, the values of the real and imaginary shear module are obtained at a frequency of 74 kHz. The measurements are performed with a liquid layer thickness much smaller than the shear wavelength. It is shown that the shear modulus decreases with increasing strain amplitude. A hole-cluster model based on the Isakovich- Chaban nonlocal diffusion theory is proposed for explaining the low-frequency viscoelastic relaxation process.DOI: http://dx.doi.org/10.5564/pmas.v0i4.46 Proceedings of the Mongolian Academy of Sciences 2009 No 4 pp.53-58

OS02-4-2 Temperature dependences of elastic constants and internal friction of α-quartz near α-β phase transformation studied by antenna-transmission noncontacting acoustic resonance method

OS02-4-2 Temperature dependences of elastic constants and internal friction of α-quartz near α-β phase transformation studied by antenna-transmission noncontacting acoustic resonance method

C212 電磁超音波共鳴法による配管減肉のオンラインモニタリング(OS6 減肉検査・モニタリングおよび劣化時の材料強度)

In this study, Electromagnetic Acoustic Resonance method (EMAR) is applied to online monitoring of pipe wall thinning, and accuracy and stability of measurement is discussed through field tests using a large-scale corrosion test loop. Although EMAR has a high capability of evaluating thickness or ultrasonic velocity, targets are usually limited to ones with simple geometry such as plates. In order to measure thickness of pipes with complicated wall thinning, superposition of nth compression for data processing method is applied to extract thickness information from spectral responses. Results of two-month monitoring show that EMAR with the proposed signal processing method has a capability of evaluating pipe wall thinning with the accuracy of several m at high temperature of 165 degrees C.

Ideal-Gas Heat Capacity for 2,3,3,3-Tetrafluoropropene (HFO-1234yf) Determined from Speed-of-Sound Measurements

The isobaric ideal-gas heat capacity for HFO-1234yf, which is expected to be one of the best alternative refrigerants for HFC-134a, was determined on the basis of speed-of-sound measurements in the gaseous phase. The speed of sound was measured by means of the acoustic resonance method using a spherical cavity. The resonance frequency in the spherical cavity containing the sample gas was measured to determine the speed of sound. After correcting for some effects such as the thermal boundary layer and deformation of the cavity on the resonance frequency, the speed of sound was obtained with a relative uncertainty of 0.01 %. Using the measured speed-of-sound data, the acoustic-virial equation was formulated and the isobaric ideal-gas heat capacity was determined with a relative uncertainty of 0.1 %. A temperature correlation function of the isobaric ideal-gas heat capacity for HFO-1234yf was also developed.