MEASUREMENT OF LOCAL POROSITY OF PARTICLES REINFORCED COMPOSITES WITH THE LASER OPTOACOUSTIC METHOD

Similar documents
Measurement of local elastic modulus with CLUE

Measurement of acousto-elastic effect by using surface acoustic wave

Nondestructive Determination of Elastic Constants of Thin Plates Based on PVDF Focusing Ultrasound Transducers and Lamb Wave Measurements

Measurement of the optical absorption coefficient of a liquid by use of a time-resolved photoacoustic technique

MODELING OF ACOUSTIC PROCESSES IN SOLIDS BASED ON PARTICLE INTERACTION

ULTRASONIC INSPECTION, MATERIAL NOISE AND. Mehmet Bilgen and James H. Center for NDE Iowa State University Ames, IA 50011

Evaluation of transverse elastic properties of fibers used in composite materials by laser resonant ultrasound spectroscopy

Pulse-echo method can't measure wave attenuation accurately

Silicon wafer characterisation by laser ultrasonics and neural networks

Nondestructive Monitoring of Setting and Hardening of Portland Cement Mortar with Sonic Methods

Absolute Nonlinear Parameter Estimation using Relative Nonlinear Parameter measured from Surface Acoustic Wave

ULTRASONIC TESTING OF RAILS INCLUDING VERTICAL CRACKS-

Ultrasonics 50 (2010) Contents lists available at ScienceDirect. Ultrasonics. journal homepage:

SUBSURFACE WAVES IN SOLIDS WITH CURVED SURFACE AND ACOUSTICAL IMPEDANCE ON IT

Non-Destructive Testing of Concrete Based on Analysis of Velocity Dispersion of Laser Ultrasonics

Nanoacoustics II Lecture #2 More on generation and pick-up of phonons

Nonlinear surface acoustic wave pulses in solids: Laser excitation, propagation, interactions invited

Doppler echocardiography & Magnetic Resonance Imaging. Doppler echocardiography. History: - Langevin developed sonar.

ABSTRACT 1. INTRODUCTION

Workshop 2: Acoustic Output Measurements

13th International Symposium on Nondestructive Characterization of Materials (NDCM-XIII), May 2013, Le Mans, France

ESTIMATION OF LAYER THICKNESS BY THE COST FUNCTION OPTIMIZATION: PHANTOM STUDY

Non-linear Aspects of Friction Material Elastic Constants

ATTENUATION AND POROSITY ESTIMATION USING THE FREQUENCY-INDEPENDENT PARAMETER Q

ACOUSTIC EMISSION SOURCE DETECTION USING THE TIME REVERSAL PRINCIPLE ON DISPERSIVE WAVES IN BEAMS

Elastic Constants and Microstructure of Amorphous SiO 2 Thin Films Studied by Brillouin Oscillations

Tensile Stress Acoustic Constants of Unidirectional Graphite/Epoxy Composites

ACOUSTIC EFFECTS OCCURRING IN OPTICAL BREAKDOWN WITH A LIQUID BY LASER RADIATION

Measurement of Elastic Constants Using Ultrasound

Angular Spectrum Decomposition Analysis of Second Harmonic Ultrasound Propagation and its Relation to Tissue Harmonic Imaging

On the study of elastic wave scattering and Rayleigh wave velocity measurement of concrete with steel bar

THE EFFECT OF CEMENTATION ON THE SEISMIC PROPERTIES OF SANDSTONE:

Development of PC-Based Leak Detection System Using Acoustic Emission Technique

Research Article Travel-Time Difference Extracting in Experimental Study of Rayleigh Wave Acoustoelastic Effect

Microwave-induced thermoacoustic tomography using multi-sector scanning

Optical and Photonic Glasses. Lecture 30. Femtosecond Laser Irradiation and Acoustooptic. Professor Rui Almeida

Finite Element Modeling of Ultrasonic Transducers for Polymer Characterization

MATERIALS CHARACfERIZA TION USING ACOUSTIC NONLINEARITY PARAMETERS AND HARMONIC GENERATION: ENGINEERING MATERIALS. William T. Yost

Absolute Measurement and Relative Measurement of Ultrasonic Nonlinear Parameters

ULTRASONIC MEASUREMENT OF IN-PLANE MODULI OF PULTRUDED COMPOSITES

Research on sound absorbing mechanism and the preparation of new backing material for ultrasound transducers

Signal Loss. A1 A L[Neper] = ln or L[dB] = 20log 1. Proportional loss of signal amplitude with increasing propagation distance: = α d

Terahertz acoustics with multilayers and superlattices Bernard Perrin Institut des NanoSciences de Paris

Phononic Crystals. J.H. Page

Acoustic Velocity, Impedance, Reflection, Transmission, Attenuation, and Acoustic Etalons

laser with Q-switching for generation of terahertz radiation Multiline CO 2 Journal of Physics: Conference Series PAPER OPEN ACCESS

Solid State Physics (condensed matter): FERROELECTRICS

Industrial Materials Research Institute NRC, Boucherville, Quebec, Canada *Almax Industries Ltd. Linday, Ontario, Canada

MEASUREMENT OF ACOUSTOELASTIC EFFECT OF RAYLEIGH SURFACE WAVES USING LASER ULTRASONICS

A COMPARISON OF DIFFERENT METHODS FOR THE DETECTION OF A WEAK ADHESIVE/ADHEREND INTERFACE IN BONDED JOINTS

FATIGUE DAMAGE PROGRESSION IN PLASTICS DURING CYCLIC BALL INDENTATION

Attenuation and dispersion

FROM NEAR FIELD TO FAR FIELD AND BEYOND

APPLICATION OF DETONATION TO PROPULSION. S. M. Frolov, V. Ya. Basevich, and V. S. Aksenov

Step index planar waveguide

ULTRASONIC WAVE PROPAGATION IN DISSIMILAR METAL WELDS APPLICATION OF A RAY-BASED MODEL AND COMPARISON WITH EXPERIMENTAL RESULTS

The structure of laser pulses

SLIDE NOTES. Notes on COVER PAGE

CO 2 Rock Physics: A Laboratory Study

PROPERTY STUDY ON EMATS WITH VISUALIZATION OF ULTRASONIC PROPAGATION

Interaction of laser-generated surface acoustic pulses with fine particles: Surface cleaning and adhesion studies

Sound Radiation Of Cast Iron

ELASTIC MODULI OF SILICON CARBIDE PARTICULATE REINFORCED ALUMINUM METAL MATRIX COMPOSITES

Lecture #8 Non-linear phononics

Optimisation using measured Green s function for improving spatial coherence in acoustic measurements

Ultrasonic particle and cell separation and size sorting

Porous Materials for Sound Absorption and Transmission Control

6th NDT in Progress Lamb waves in an anisotropic plate of a single crystal silicon wafer

Ultrasonic Monitoring and Evaluation of Very High Cycle Fatigue of Carbon Fiber Reinforced Plastics

AN ANALYSIS OF ULTRASONIC WAVE GENERATED BY OBLIQUE INCIDENCE OF LASER

ULTRASONIC ATTENUATION RESULTS OF THERMOPLASTIC RESIN COMPOSITES UNDERGOING THERMAL AND FATIGUE LOADING

2. Theoretical Model: Wave propagation in anisotropic elastic materials

A FEM STUDY ON THE INFLUENCE OF THE GEOMETRIC CHARACTERISTICS OF METALLIC FILMS IRRADIATED BY NANOSECOND LASER PULSES

ULTRASONIC A TTENUA TION RESULTS OF THERMOPLASTIC RESIN COMPOSITES UNDERGOING THERMAL AND FATIGUE LOADING

SIMULATION OF ULTRASONIC NDT IN COMPOSITE RADIUS

Shear waves in solid-state materials

MEASUREMENT OF REFLECTANCE FUNCTION FOR LAYERED STRUCTURES USING FOCUSED ACOUSTIC WAVES INTRODUCTION

VISUALIZATION OF SOUND PROPAGATION WITH ELECTRODYNAMIC PROBES

A TWO-LAYER MODEL FOR THE LASER GENERATION OF ULTRASOUND IN

ACOUSTIC EMISSION FROM IMPACTS OF RIGID BODIES

EFIT SIMULATIONS FOR ULTRASONIC NDE

The Physics of Doppler Ultrasound. HET408 Medical Imaging

Nonlinear-optical approach to problem of space debris tracking and removal O. Kulagin, I. Gorbunov

Output intensity measurement on a diagnostic ultrasound machine using a calibrated thermoacoustic sensor

[Yadav*, 5(3): March, 2016] ISSN: (I2OR), Publication Impact Factor: 3.785

Lamb Wave Behavior in Bridge Girder Geometries

Laser Supported Detonation in Silica-based Optical Fibers

Health Monitoring of Early Age Concrete

1532 J. Acoust. Soc. Am. 102 (3), September /97/102(3)/1532/8/$ Acoustical Society of America 1532

UNIVERSITY OF SOUTHAMPTON

Thickness Measuring of Thin Metal by Non Destructive with Fuzzy Logic Control System

Evaluation of elastic properties of iron in diamond anvil cell by laser ultrasonics technique

Investigation of Ultrasonic Properties of Hydrophilic Polymers for Dry-coupled Inspection

Interaction of weak shocks leading to Mach stem formation in focused beams and reflections from a rigid surface: numerical modeling and experiment

EVALUATING THERMALLY DAMAGED POLYIMIDE INSULATED WIRING (MIL-W-81381) WITH ULTRASOUND

Time Scale of the Quaternary Structural Change in Hemoglobin Revealed by Transient Grating Technique

QUANTITATIVE TIIERMAL DIFFUSIVITY MEASUREMENTS ON COMPOSITE

THE ULTRASONIC FIELD OF FOCUSED TRANSDUCERS THROUGH A LIQUID- M. EI Amrani Intercontrole 13 rue du Capricome, Rungis Cedex, France

INFLUENCE OF INITIAL DENSITY ON THE REACTION ZONE FOR STEADY-STATE DETONATION OF HIGH EXPLOSIVES

Case Study: Residual Stress Measurement

Transcription:

MEASUREMENT OF LOCAL POROSITY OF PARTICLES REINFORCED COMPOSITES WITH THE LASER OPTOACOUSTIC METHOD A.A. KARABUTOV, N.B. PODYMOVA, L.I. KOBELEVA*, T.A. CHERNYSHOVA* INTERNATIONAL LASER CENTER, M.V. LOMONOSOV MOSCOW STATE UNIVERSITY Leninskie Gory, Moscow 119991, Russia e-mail: npodymova@mail.ru Abstract *A.A. BAIKOV INSTITUTE OF METALLURGY AND MATERIALS SCIENCE 49 Leninsky pr., Moscow 117334, Russia In the present work we have proposed and realized experimentally the laser optoacoustic method for the measurements of local porosity of isotropic composite materials. It is based on measurements of phase velocities of thermooptically excited longitudinal acoustic waves in composite samples. The results of local porosity measurements (lateral resolution 1 mm) for a number of aluminum alloy (silumin) matrix composite samples reinforced by SiC particles of a different mass concentration with the mean particle size of 14 µm coincide within relative inaccuracy -3% with the gravimetrical measurements of the average <P> value. 1. Introduction The problem of nondestructive testing of the actual state of composite materials is of great importance because of essential decrease of their strength caused by defects and structural changes of a material that arise during exploitation [1]. In particular, fatigue changes of composite structure lead to the increase of the volume fraction of pores (porosity) that in turn leads to the decrease of material strength even by the absence of apparent defects. So the development of local porosity measurement methods is of great practical importance to provide valuable information for residual service life evaluation of composite products. Typical structural fatigue changes lead to the change of attenuation and velocity of ultrasonic waves in composite materials. So one of the most widely used techniques of nondestructive testing of composites is the ultrasonic method []. It is based on the analysis of frequency dependencies of attenuation coefficient and phase velocity of acoustic waves in a material under study [3]. Composites are acoustically inhomogeneous materials, so to provide the quantitative evaluation of structural features one needs to carry out measurements of attenuation coefficient and phase velocity in a wide frequency band. This is due to the increase of scattering efficiency of ultrasonic waves, when its length becomes of the order of the structural inhomogeneities size. Besides the significant attenuation of ultrasound in composite materials requires the utilization of sources of powerful wideband acoustic signals. Therefore it is quite difficult to carry out the testing of samples and items of several centimeters thickness with conventional piezoelectrical transducers because of low efficiency of wideband acoustic signals excitation [4]. 1

To overcome the difficulties of conventional ultrasonic techniques mentioned above we propose to employ the laser thermooptical excitation of ultrasound pulse optoacoustic effect [5]. The main goal of the present work is the development of laser optoacoustic method of local porosity measurements of isotropic composite materials.. Investigated composite samples In the present work a number of aluminum alloy (silumin) matrix composite samples reinforced by SiC particles of a different mass concentration was investigated. The samples have been manufactured by casting of molten silumin mixed with the certain amount of the fine powder of SiC particles with the mean size of 14 µm. The porosity <P> averaged over the entire volume of the sample is expressed as: ( 1 ρ 0 ) 100 % < P >= ρ, (1) where the calculated density of the sample ρ 0 is determined with the known densities of the matrix silumin ρ Al =,735 10 3 kg/m 3, of the filler SiC ρ SiC = 3, 10 3 kg/m 3, and with the known mass concentrations n Al and n SiC ; the actual density of the sample ρ is measured gravimetrically. The characteristics of the investigated samples are presented in the Table 1. Table 1. Characteristics of investigated samples sample # Thickness H, mm Mass concentration of components n Calculated density ρ0, 10 3 kg/m 3 Actual density ρ, 10 3 kg/m 3 Averaged porosity <P>, % silumin SiC 1 10,70 1,0 0,0,735,714 0,77 10,18 0,96 0,038,750,710 1,45 3 10,98 0,93 0,077,766,665 3,65 4 4,7 0,845 0,155,798,660 4,93 The local porosity in different sites of a sample could be different because of nonuniform reinforcing fabrication method. To determine the local porosity P we use the theoretical model of ultrasound propagation in a porous metal [6], where the phase velocity of longitudinal acoustic waves in a material c l depends on P as follows (at the values of P < 0%): ( 1 P 3 ) c c l =, () l 0 where c l 0 is the calculated with the two-phase medium model [7] phase velocity in the investigated site of a sample:

α, см - 1 8 8 7 7 6 5 4 4 3 3 1 1 0 0 5 10 15 0 5 30 35 40 часто таf, МГц c = l 0 1 ρ 0 1 nsic n + Al ( ) ( ) ρ SiC cl ρ SiC Al cl Al. (3) In the expression (3) c l SiC = 11,8 10 3 m/s, c l Al = 6,86 10 3 m/s are the known phase velocities in the filler and in the matrix [8, 9]. So to determine the local porosity P from the expression () we have to measure the phase velocity of longitudinal acoustic waves c l in the corresponding site of the sample under study. 3. Experimental technique of phase velocity measurement of longitudinal acoustic waves Experimental laser optoacoustic setup is shown in the Figure 1. A pulse of Q-switched Nd:YAG laser at the fundamental harmonic is absorbed in the specially designed optoacoustic (OA) source the plate of optical filter blue-green glass, that causes the nonuniform non-stationary heating of subsurface layer of OA source and corresponding rise of the nonuniform mechanical stress. This in turn leads to excitation of the pulse of longitudinal acoustic waves (OA signal). The employment of Q-switched lasers and appropriate OA sources allows one to achieve the amplitude of OA signals up to hundreds of MPa in the frequency range up-to hundreds of MHz. Nd:YAG laser t L = 10ns l =1.064 mm OA source (blue-green glass) synchropulse sample piezoelectric detector immersion liquid digital oscilloscope TDS100 X Y К оэфф ици ент затух ания пр одол ьны хул ьтразву ковы х вол н 333 33 333 33 PC Figure 1. Laser optoacoustic setup The OA signal excited in the OA source the reference ultrasonic pulse passes through an investigated sample and is detected with the specially designed wideband piezoelectric receiver 3

being in the acoustic contact with the sample through the immersion liquid (distilled water) (see Figure 1). The OA source, the sample and the receiver are mounted in the special OA cell. Figure shows the temporal profile and the amplitude spectrum of the reference ultrasonic pulse of blue-green glass OA source. The small duration and the large amplitude of the reference pulse allow to test the composite samples of a thickness from hundreds of microns to several centimeters, and also for strong scattering and absorptive materials (with the ultrasound attenuation coefficient value up to 10 0 cm -1 ). OA signal U(t), V 0,8 0,6 0,4 0, 0,0-0, -0,4-0,6 4,5 4,6 4,7 4,8 4,9 5,0 5,1 5, 5,3 5,4 5,5 time t, ms а Spectral ampl. S( f ), rel.units 1,0 b 0,8 0,6 0,4 0, 0,0 0 5 10 15 0 5 30 35 40 45 50 frequency f, MHz Figure. Temporal profile (a) and amplitude spectrum (b) of the reference ultrasonic pulse The cross-section of the reference ultrasonic beam irradiated into the sample coincides with the mean diameter of the laser beam and is approximately 1,5 mm. This dimension determines the locality of testing in the lateral plane. Electrical signals from the piezoelectric receiver come in the two-channel digital oscilloscope Tektronix TDS 100 (analog bandwidth 100 MHz), the signal-to-noise ratio for the registration system is 50 60 db. The amplitude and phase spectra of acoustic signals are calculated with the standard code of the fast Fourier transform (FFT) taken into account the reflection coefficients of acoustic waves at the sample - immersed liquid interfaces in the optoacoustic cell and also the diffraction effect on the spectra of pulses. The frequency dependencies of the attenuation coefficient and the phase velocity of longitudinal acoustic waves in the sample are calculated in real time due to high signal-to-noise ratio and high stability of temporal profile of the reference ultrasonic pulses. The main characteristics of the laser optoacoustic system are presented in the Table. 4

Table. Characteristics of the laser optoacoustic system Ultrasonic frequency band Amplitude of ultrasonic pressure Sample thickness Lateral locality of testing 0,5 50 MHz 0,01 10 MPa 0,1 70 mm 1 mm The absolute value and the dispersion of the phase velocity c l of longitudinal acoustic waves in the sample of the known thickness H are determined from the measured phase spectra of the reference ultrasonic pulse, ϕ 0( f ), and of the ultrasonic pulse passed through the sample, ϕ ( f ) : π f H c l ( f ) =. (4) ϕ ( f ) ϕ0( f ) To enhance the accuracy of the phase velocity measurements it is useful to determine the phase difference of the ultrasonic pulse once passed through the sample, and of the pulse after the tripple pass in the sample passed through the sample and reflected at the sample-immersed liquid interfaces. So the uncontrolled influence of possible difference in the liquid layers thickness could be eliminated by the mounting of OA cell for detection of the reference signal without the sample and the OA cell with the sample. The absolute value of the phase velocity of longitudinal acoustic waves is determined as follows in the absence of the significant dispersion (the relative change of velocity doesn t exceed 5 10% in the investigated frequency band 0,5 50 MHz): cl H =, (5) Tl where Tl is the difference of arrival times to the receiver of the ultrasonic pulse once passed through the sample and of the pulse after the tripple pass in the sample. As an example the typical temporal profile of these two pulses in a silumin-matrix composite sample is shown in the Figure 3 [9]. The time interval Tl is measured between the instants of transition through the zero from the compression to the rarefaction phases of the ultrasonic pulses. The attenuation of ultrasound affects on the duration of both the compression and the rarefaction phase and the single pass and the triple pass pulses cover a different distance in the sample. Therefore the duration of both the compression and the rarefaction phases will be different for these two pulses. As it follows from the theoretical model of the wideband OA signal propagation in an absorbing medium [5], just the propagation velocity of the zero point of the bipolar OA pulse is the most close to the acoustic wave phase velocity in the absence of the significant dispersion. 5

OA signal U(t), mv 0,6 0,5 0,4 Single pass 0,3 0, 0,1 0,0-0,1-0, -0,3-0,4 T l -0,5 5,00 5,5 5,50 5,75 6,00 6,5 6,50 6,75 7,00 7,5 time t, ms Triple pass Figure 3. Typical temporal profile of the OA pulse of longitudinal acoustic waves once passed through the silumin-matrix composite sample and after the tripple pass in the sample [9]. The small duration of the longitudinal acoustic wave pulses provides sufficiently low relative inaccuracy of the phase velocity measurement: δ ( c l ) 0,5%. This value is governed basically by the relative inaccuracy of the sample thickness measurement: δh 0,5%, because of the value of T l (see Figure 3) is determined accurate within 3 ns, that is of the order of 10-3 Tl for the sample thickness H ~ 10 mm. 4. Experimental results Phase velocities of longitudinal acoustic waves in the composite samples under study were measured by the procedure described in the Section 3 and calculated with the expression (5). As the test samples with the known values of phase velocities of longitudinal acoustic waves a number of aluminum and copper samples have been studied. The experimental results of the optoacoustic measurement and the referenced data [8] for these samples are presented in the Table 3. The experimental results coincide within the inaccuracy limits with the referenced data. This fact confirms the reliability of the laser optoacoustic method for the measurement of the phase velocity of longitudinal acoustic waves in isotropic solid samples. Table 3. Comparison of optoacoustic measurement results and referenced data material c l, m/s OA measurements Referenced data [8] Al 680 ± 30 660 Cu 470 ± 0 4700 6

All composite samples were the discs of the diameter d = 40 mm. We determined the porosity in the center (P 1 ) and in the periphery (P ) sites of each sample using the expression () with the measured values of the phase velocities in these sites c l1 and c l and the calculated value of (3) for the given sample (see the Table 4). The relative inaccuracy of 0,5% of the phase velocity measurements leads to the relative inaccuracy of 3% of porosity determination. The experimental c l 0 results show (Table 4), that the increase of the mass concentration of the filler n SiC leads to the growth of the sample porosity P. All investigated samples have quite uniform distribution of pores, the local porosity values coincide within the inaccuracy limits with the gravimetrical measurements of the average <P> value. The porosity in the center of each sample is slightly higher than in the periphery. Table 4. Results of optoacoustic measurements sample # n SiC c, m/s c l1, m/s c l, m/s P 1, % P, % <P>, % l 0 1 0,00 6860 6670 6730 1,30±0,03 0,77±0,0 0,77 0,038 690 670 6740 1,43±0,03 1,18±0,0 1,45 3 0,077 6990 6550 6590 4,4±0,09 3,69±0,07 3,65 4 0,155 7140 6660 6680 4,69±0,09 4,41±0,09 4,93 5. Conclusions In the present work we have proposed and realized the laser optoacoustic method for local porosity measurement of isotropic composite materials. It can be applied also for any type of constructional materials (metals, alloys, plastics), when the size of pores is in the micron range. This method allows one to investigate samples of the thickness of 0,1 70 mm with the lateral resolution of 1 mm. The maximum relative inaccuracy of porosity measurement is 3 %. The proposed laser optoacoustic method may be useful by technological development and improvement of the materials fabrication process and to reveal the sites in a material with the less strength before manufacturing of items and products. References 1. Handbook of Composites (ed. Herakovich C.T. and Tarnopol skii Yu.M.). Elsevier Science Pbl., 1988, 165 ps.. Vary A. Ultrasonic measurements of material properties. // Research Techniques in Nondestructive Testing, 1980, v. 4, p. 160-04. 7

3. Fitting D.W., Adler L. Ultrasonic spectral analysis for nondestructive evaluation. Plenum Press, 1981, 354 ps. 4. Truell R., Elbaum C., Chick B. Ultrasonic methods in solid state physics. Academic Press, 1969, 308 ps. 5. Gusev V.E., Karabutov A.A. Laser Optoacoustics. AIP, 1993, 9 ps. 6. Polyakov V.V., Golovin V.A. Influence of porosity on ultrasonic wave velocity in metals. // Technical Physics Lett., 1994, v. 0, 11, p. 54-57. 7. Zharkii S.M., Karabutov А.А., Pelivanov I.M., Podymova N.B., Timoshenko V.Yu. Laser ultrasonic study of porous silicon layers. // Semiconductors, 003, v. 37, 4, p. 468-47. 8. Handbook of Physical Quantities (ed. Grigoriev I.S., Meilikhov E.Z. and Radzig A.A.). CRC- Press, 1997, 1395 ps. 9. Karabutov А.А., Kobeleva L.I., Podymova N.B., Chernyshova T.A. Measurement of elastic moduli of particle reinforced composites with the laser optoacoustic method. // Zavodskaya Laboratoriya - Diagnostika Materialov, 009, v. 75, 3, p. 7-33 (in Russian). 8