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Albert P. Pisano - One of the best experts on this subject based on the ideXlab platform.
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the multi mode resonance in aln Lamb Wave resonators
IEEE\ ASME Journal of Microelectromechanical Systems, 2018Co-Authors: Jie Zou, Chih-ming Lin, Anming Gao, Albert P. PisanoAbstract:The characteristics of the multi-mode resonance behavior of AlN Lamb Wave resonators (LWRs) are theoretically and experimentally investigated for the first time in this paper. Adler’s approach and finite element method (FEM) are used to calculate the dispersive characteristics of the phase velocity ( $v_{p}$ ), group velocity ( $v_{g}$ ), effective coupling coefficient ( $k^{2}_{\text {eff}}$ ), and temperature coefficient of frequency for the first eight Lamb Wave modes with different transducer configurations. The FEM is performed to take an insight into the mode shapes of the S0 mode and S1 mode specifically: the S0 mode is more contour-like and exhibits the largest $k^{2}_{\text {eff}}$ when $h_{\text {AlN}}/\Lambda $ is close to 0.5; the S1 mode is strong in vertical direction and can enable high resonance frequency ( $f_{s}$ ) and large $k^{2}$ simultaneously when AlN thickness is very thin. Experimentally, AlN LWRs with different AlN thicknesses are designed and fabricated. The measured results are fitted into the multi-resonance BVD model so that the device performance parameters, as well as the equivalent, lumped element values are extracted and compared. By choosing different normalized AlN thicknesses, the performance of different Lamb Wave modes varies largely due to the dispersive characteristics and agrees well with theoretically predicted acoustic characteristics. This paper lays the foundation for characterizing the multi-resonance behaviors of AlN LWRs and gives guidance on choosing the optimal design parameters and Lamb Wave modes for different applications. [2018-0040]
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transducer design for aln Lamb Wave resonators
Journal of Applied Physics, 2017Co-Authors: Jie Zou, Chih-ming Lin, C. S. Lam, Albert P. PisanoAbstract:AlN Lamb Wave resonators enjoy advanced and attractive properties for enabling the next-generation single-chip radio frequency front-end, but their moderate effective electromechanical coupling coefficient (k2eff) poses a limit to their application in filters and multiplexers. Despite the fact that the reported k2eff enhancement techniques of doped AlN thin films which are expensive and trade off the quality factor (Q), the transducer topology itself extensively impacts the k2eff value. Although an AlN cross-sectional Lame mode resonator exhibiting a k2eff of 6.34% has been demonstrated without the need for changing the piezoelectric material, a detailed study of transducer design for AlN Lamb Wave resonators has not been conducted. In this work, we investigate the impact of (i) transducer configurations, (ii) electrode materials, (iii) electrode thicknesses, and (iv) interdigital transducer duty factors on the k2eff dispersive characteristics of one-port AlN Lamb Wave resonators by using the finite eleme...
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High-Q capacitive-piezoelectric AlN Lamb Wave resonators
2013 IEEE 26th International Conference on Micro Electro Mechanical Systems (MEMS), 2013Co-Authors: Albert P. Pisano, Clark T.-c. NguyenAbstract:The use of capacitive-piezoelectric transducers, formed by separating a piezoelectric structure from its electrodes by sub-micron gaps, has raised the measured quality factor of aluminum nitride (AlN) Lamb Wave resonators (LWR) from the ~1,000 of typical square-edged conventional devices (with contacting electrodes) to over 5,000 at 940 MHz, posting the highest reported Q for non-overmoded pure AlN resonators using d31 (e31) transduction at this frequency range. The Q · f product achieved here is significantly higher than that of a previous 1.2-GHz capacitive-piezoelectric contour-mode ring, mainly due to the use of Lamb Wave modes that allow better support isolation to prevent energy loss to the substrate. In addition, the use of interdigital transducer (IDT) electrodes successfully decouples the resonance frequency from overall device dimensions, offering a CAD-definable design parameter for fine-frequency control. The effective coupling coefficient of keff2 = 0.3% achieved by this device is lower than the 1.6% typically observed for conventional AlN Lamb Wave resonators, but still sufficient to avoid pass-band distortion in the 0.1% bandwidth filters needed for next-generation RF channel-selecting communication front-ends.
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Dispersion characteristics of high-order Lamb Wave modes in an AlN/3C-SiC layered plate
2012 IEEE International Ultrasonics Symposium, 2012Co-Authors: Chih-ming Lin, Debbie G. Senesky, Yung-yu Chen, Viktoria V Felmetsger, Albert P. PisanoAbstract:A new propagation layered media composed of a piezoelectric thin film and a substrate plate is studied in this work. The displacement profiles, phase velocities, and electromechanical coupling coefficients of Lamb Wave modes are theoretically investigated for the c-axis oriented AlN films on cubic silicon carbide (3C-SiC) plates. Due to the different material properties of the AlN and 3C-SiC layers, the displacement profiles of Lamb Wave modes are not simply antisymmetric or symmetric with respect to the neutral axis. According to the displacement profiles, the plate acoustic Wave modes in the layered plate are classified as quasi-Lamb Wave modes. Some high-order quasi-Lamb Wave modes in the layered plate have larger electromechanical couplings than the corresponding Lamb Wave modes in an AlN thin plate. In addition, the third quasi-symmetric (QS3) Lamb Wave mode exhibits a low motional impedance (Rm) of 91 ohm and a high quality factor (Q) up to 5510 at a frequency (fs) of 2.92 GHz, resulting in the highest fs·Q product, 1.61×1013 Hz, among suspended piezoelectric thin film resonators reported to date.
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high q aluminum nitride Lamb Wave resonators with biconvex edges
Applied Physics Letters, 2011Co-Authors: Yung-yu Chen, Debbie G. Senesky, Albert P. PisanoAbstract:A Lamb Wave resonator utilizing an aluminum nitride (AlN) plate with biconvex edges to enhance the quality factor (Q) is demonstrated. The simulation results based on finite element analysis verify that the use of the biconvex edges, instead of the conventional flat edges, can efficiently confine mechanical energy in the AlN Lamb Wave resonator. Specifically, the measured frequency response of a 491.8-MHz AlN Lamb Wave resonator with biconvex edges yields a Q of 3280 which represents a 2.6× enhancement in Q over a 517.9-MHz Lamb Wave resonator on the same AlN plate but with the suspended flat edges.
Mark K. Hinders - One of the best experts on this subject based on the ideXlab platform.
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Ultrasonic Lamb Wave tomography
Inverse Problems, 2002Co-Authors: Kevin R. Leonard, Eugene Malyarenko, Mark K. HindersAbstract:Nondestructive evaluation (NDE) of aerospace structures using traditional methods is a complex, time-consuming process critical to maintaining mission readiness and flight safety. Limited access to corrosion-prone structure and the restricted applicability of available NDE techniques for the detection of hidden corrosion or other damage often compound the challenge. In this paper we discuss our recent work using ultrasonic Lamb Wave tomography to address this pressing NDE technology need. Lamb Waves are ultrasonic guided Waves, which allow large sections of aircraft structures to be rapidly inspected for structural flaws such as disbonds, corrosion and delaminations. Because the velocity of Lamb Waves depends on thickness, for example, the travel times of the fundamental Lamb modes can be converted into a thickness map of the inspection region. However, extracting quantitative information from Lamb Wave data has always involved highly trained personnel with a detailed knowledge of mechanical Waveguide physics. Our work focuses on tomographic reconstruction to produce quantitative maps that can be easily interpreted by technicians or fed directly into structural integrity and lifetime prediction codes. Laboratory measurements discussed here demonstrate that Lamb Wave tomography using a square perimeter array of transducers with algebraic reconstruction tomography is appropriate for detecting flaws in aircraft materials. The speed and fidelity of the reconstruction algorithms as well as practical considerations for person-portable array-based systems are discussed in this paper.
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Blind test of Lamb Wave diffraction tomography
AIP Conference Proceedings, 2002Co-Authors: Mark K. Hinders, Kevin R. Leonard, Eugene MalyarenkoAbstract:Lamb Waves are guided ultrasonic Waves capable of propagating relatively long distances in plates and laminated structures, such as airframe skins, storage tanks and pressure vessels. Their propagation properties in these media depend on the vibrational frequency as well as on the thickness and material properties of the structure. Structural flaws such as disbonds, corrosion and fatigue cracks represent changes in effective thickness and local material properties, and therefore measurement of variations in Lamb Wave propagation can be employed to assess the integrity of these structures. Lamb Wave measurements can be made for a number of relative transducer positions (projections) and an image of the flawed region can be reconstructed tomographically to give a quantitative map of a quantity of interest, e.g. thickness loss due to corrosion. As a test of the Lamb Wave scanning apparatus and diffraction tomography reconstruction algorithms, we have undertaken an experiment which is double-blind in the medical sense. Since our motivation is identifying flaws in aging aircraft structures, we have purchased a number of identical aluminum plates, into which representative flaws have been introduced prior to scanning with our existing Lamb Wave tomography system and verification with traditional ultrasonic C-scans in an immersion tank. All personnel “calling the flaws” from the reconstructions are blinded from both the Lamb Wave and immersion scanning results, with scoring metrics determined before hand. These and other results will be presented in this talk.
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Ultrasonic Lamb Wave tomographic scanning
Nondestructive Evaluation of Aging Aircraft Airports and Aerospace Hardware III, 1999Co-Authors: Mark K. Hinders, Eugene Malyarenko, James C. P. MckeonAbstract:Lamb Waves are guided ultrasonic Waves capable of propagating relatively long distances in plate-like structures such as airframe skins. Their propagation depends on frequency-thickness and material properties, and because structural flaws present changes in effective thickness and/or material properties Lamb Waves can be employed to assess the integrity of these structures. For aging aircraft structures a full integrity evaluation can be a time- consuming operation, but with Lamb Wave techniques this evaluation can be performed with Waves propagating along one dimension of the inspection area as the probing transducer pair is moved in the perpendicular dimension. Such an approach yields information about the presence of flaws within the scanned area. Then, in order to quantitatively characterize the flaws, Lamb Wave measurements can be made for a number of projections and an image of the flawed region can be reconstructed tomographically. In this paper, contact scanning Lamb Wave tomography for metallic aircraft structures with flaws is discussed as a practical technique for quantitative nondestructive evaluation.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
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Lamb Wave Contact Scanning Tomography
Review of Progress in Quantitative Nondestructive Evaluation, 1999Co-Authors: James C. P. Mckeon, Mark K. HindersAbstract:Lamb Waves are guided ultrasonic Waves capable of propagating relatively long distances in thin plates and thin laminated structures, such as airframe skins, storage tanks and pressure vessels. Their propagation properties in these media depend on the vibrational frequency as well as on the thickness and or material properties of the structure. Structural flaws such as disbonds, corrosion and fatigue cracks represent changes in effective thickness and material properties, and therefore measurement of variations in Lamb Wave propagation can be employed to assess the integrity of these structures. Lamb Wave measurements can be made for a number of relative transducer positions (projections) and an image of the flawed region can be reconstructed tomographically. This paper presents a new technique in which two contact piezoelectric transducers are independently scanned along parallel lines in a fashion analogous to that commonly used in seismic crosshole tomography. These results are compared to those for parallel projection Lamb Wave tomography data collected with an automated contact scanning apparatus. The advantages and drawbacks of these two methods in the development of automated tomographic Lamb Wave scanners for quantitative mapping of thickness variation in plate-like materials are discussed.
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Lamb Wave Tomography for Corrosion Mapping
1999Co-Authors: Mark K. Hinders, James C. P. MckeonAbstract:As the world-wide civil aviation fleet continues to age, methods for accurately predicting the presence of structural flaws-such as hidden corrosion-that compromise airworthiness become increasingly necessary. Ultrasonic guided Waves, Lamb Waves, allow large sections of aircraft structures to be rapidly inspected. However, extracting quantitative information from Lamb Wave data has always involved highly trained personnel with a detailed knowledge of mechanical-Waveguide physics. Our work focuses on using a variety of different tomographic reconstruction techniques to graphically represent the Lamb Wave data in images that can be easily interpreted by technicians. Because the velocity of Lamb Waves depends on thickness, we can convert the travel times of the fundamental Lamb modes into a thickness map of the inspection region. In this paper we show results for the identification of single or multiple back-surface corrosion areas in typical aluminum aircraft skin structures.
Chih-ming Lin - One of the best experts on this subject based on the ideXlab platform.
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the multi mode resonance in aln Lamb Wave resonators
IEEE\ ASME Journal of Microelectromechanical Systems, 2018Co-Authors: Jie Zou, Chih-ming Lin, Anming Gao, Albert P. PisanoAbstract:The characteristics of the multi-mode resonance behavior of AlN Lamb Wave resonators (LWRs) are theoretically and experimentally investigated for the first time in this paper. Adler’s approach and finite element method (FEM) are used to calculate the dispersive characteristics of the phase velocity ( $v_{p}$ ), group velocity ( $v_{g}$ ), effective coupling coefficient ( $k^{2}_{\text {eff}}$ ), and temperature coefficient of frequency for the first eight Lamb Wave modes with different transducer configurations. The FEM is performed to take an insight into the mode shapes of the S0 mode and S1 mode specifically: the S0 mode is more contour-like and exhibits the largest $k^{2}_{\text {eff}}$ when $h_{\text {AlN}}/\Lambda $ is close to 0.5; the S1 mode is strong in vertical direction and can enable high resonance frequency ( $f_{s}$ ) and large $k^{2}$ simultaneously when AlN thickness is very thin. Experimentally, AlN LWRs with different AlN thicknesses are designed and fabricated. The measured results are fitted into the multi-resonance BVD model so that the device performance parameters, as well as the equivalent, lumped element values are extracted and compared. By choosing different normalized AlN thicknesses, the performance of different Lamb Wave modes varies largely due to the dispersive characteristics and agrees well with theoretically predicted acoustic characteristics. This paper lays the foundation for characterizing the multi-resonance behaviors of AlN LWRs and gives guidance on choosing the optimal design parameters and Lamb Wave modes for different applications. [2018-0040]
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transducer design for aln Lamb Wave resonators
Journal of Applied Physics, 2017Co-Authors: Jie Zou, Chih-ming Lin, C. S. Lam, Albert P. PisanoAbstract:AlN Lamb Wave resonators enjoy advanced and attractive properties for enabling the next-generation single-chip radio frequency front-end, but their moderate effective electromechanical coupling coefficient (k2eff) poses a limit to their application in filters and multiplexers. Despite the fact that the reported k2eff enhancement techniques of doped AlN thin films which are expensive and trade off the quality factor (Q), the transducer topology itself extensively impacts the k2eff value. Although an AlN cross-sectional Lame mode resonator exhibiting a k2eff of 6.34% has been demonstrated without the need for changing the piezoelectric material, a detailed study of transducer design for AlN Lamb Wave resonators has not been conducted. In this work, we investigate the impact of (i) transducer configurations, (ii) electrode materials, (iii) electrode thicknesses, and (iv) interdigital transducer duty factors on the k2eff dispersive characteristics of one-port AlN Lamb Wave resonators by using the finite eleme...
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Dispersion characteristics of high-order Lamb Wave modes in an AlN/3C-SiC layered plate
2012 IEEE International Ultrasonics Symposium, 2012Co-Authors: Chih-ming Lin, Debbie G. Senesky, Yung-yu Chen, Viktoria V Felmetsger, Albert P. PisanoAbstract:A new propagation layered media composed of a piezoelectric thin film and a substrate plate is studied in this work. The displacement profiles, phase velocities, and electromechanical coupling coefficients of Lamb Wave modes are theoretically investigated for the c-axis oriented AlN films on cubic silicon carbide (3C-SiC) plates. Due to the different material properties of the AlN and 3C-SiC layers, the displacement profiles of Lamb Wave modes are not simply antisymmetric or symmetric with respect to the neutral axis. According to the displacement profiles, the plate acoustic Wave modes in the layered plate are classified as quasi-Lamb Wave modes. Some high-order quasi-Lamb Wave modes in the layered plate have larger electromechanical couplings than the corresponding Lamb Wave modes in an AlN thin plate. In addition, the third quasi-symmetric (QS3) Lamb Wave mode exhibits a low motional impedance (Rm) of 91 ohm and a high quality factor (Q) up to 5510 at a frequency (fs) of 2.92 GHz, resulting in the highest fs·Q product, 1.61×1013 Hz, among suspended piezoelectric thin film resonators reported to date.
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theoretical investigation of Lamb Wave characteristics in aln 3c sic composite membranes
Applied Physics Letters, 2010Co-Authors: Chih-ming Lin, Yung-yu Chen, Albert P. PisanoAbstract:Cubic silicon carbide (3C–SiC) layer can provide advantages of high frequency and high quality factor for Lamb Wave devices due to the superior properties of high acoustic velocity and low acoustic loss. In this study, Lamb Wave propagation characteristics in composite membranes consisting of a c-axis oriented aluminum nitride (AlN) film and an epitaxial 3C–SiC (100) layer are investigated by theoretical calculation. The lowest symmetric mode Lamb Wave propagating along the [011] direction exhibits a phase velocity higher than 10 000 m/s and an electromechanical coupling coefficient above 2% in the AlN/3C–SiC multilayered membranes.
Xiao Chen - One of the best experts on this subject based on the ideXlab platform.
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Noise removing for Lamb Wave signals by fractional differential
Journal of Vibroengineering, 2014Co-Authors: Xiao Chen, Chenlong WangAbstract:In the ultrasonic Lamb Wave nondestructive testing and evaluation, the measured Lamb Wave signals are often mixed with noises which affect their accuracy of measurement. In the present study, a fractional differential method is proposed to remove the noise for the Lamb Wave signal. Firstly, the fractional differential of the amplitude spectrum of the received noisy signal at different orders is obtained with the fractional differential theory. Then, the characteristic parameters of the amplitude spectrum are extracted with the developed parameter estimation model. The Gaussian peak mode is used as a model to assign the amplitude spectrum of the original signal correctly. Finally, the Waveform of the Lamb Wave is restored by combining the amplitude and phase spectrums. Simulated and experimental data are used to evaluate the performance of the developed method. Results show that the developed method has effective noise removing performance for Lamb Wave signals.
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Lamb Wave signal retrieval by Wavelet ridge
Journal of Vibroengineering, 2014Co-Authors: Xiao Chen, Yang Gao, Lisuo BaoAbstract:Lamb Wave testing is one of the important methods in ultrasonic nondestructive testing. One of the key technologies in the Lamb Wave testing is to get a clear signal. In this paper, a signal retrieval method for the Lamb Wave signal from noisy signals is presented on the basis of its Wavelet ridge analysis. After the Wavelet transformation, the Wavelet ridge of the Lamb Wave signal is extracted and the signal is reconstructed by using its ridge as the characteristic parameter. Experimental results show that the Lamb Wave signal is retrieved in the case of the white noise, the transient noise and the sine noise. The proposed method can retrieve the ultrasonic Lamb Wave signal effectively.
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propagation characteristic of ultrasonic Lamb Wave
Applied Mechanics and Materials, 2012Co-Authors: Xiao Chen, Kai XuAbstract:Ultrasonic Wave transmitted in the plate is called Lamb Wave. The dispersion characteristic of Lamb Wave makes it very complicated to be used in material Nondestructive Testing (NDT). In order to solve this problem, the analysis of frequency-dispersion characteristic of Lamb Wave is made in this paper, and the dispersion curves of the Lamb Wave in specific plate are plotted, then the physical propagation model of Lamb Wave is established. Under the analysis of FFT, the expressions of the Lamb Wave in specific plate are obtained. By combining with the dispersion characteristic of the Lamb Wave, the changes of Waveform in different propagation distances are simulated. With the deep researches of new algorithms, Lamb Wave will be applied in wider area.
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Wavelet Ridge Analysis of Lamb Wave
Advanced Materials Research, 2012Co-Authors: Xiao ChenAbstract:Lamb Wave has important application value in material nondestructive testing. It is a kind of ultrasonic guided Wave propagating in thin plate material. It has the dispersion characteristic, which greatly limits its wide application in material evaluation. After continuous Wavelet transformation, we extract the feature of ridge of Lamb Wave signals by adopting crazy climber algorithm. Experimental results show that Lamb Wave after transmission of a certain distance has the characteristics like asymptotic signal. The ridge can reflect the dispersion characteristic of Lamb Wave.
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computer simulation for time signal of symmetrical mode Lamb Wave
IEEE International Symposium on Knowledge Acquisition and Modeling Workshop, 2008Co-Authors: Xiao ChenAbstract:The signal processing of Lamb Wave is complex because of its multi-mode and frequency-dispersion characteristics. A method to analyze symmetrical single-mode ultrasonic Lamb Wave in the time domain is presented. Based on the analysis of frequency-dispersion characteristic of symmetrical mode Lamb Wave, we deduced the half analytic expression of its time signal, and implemented simulation computation to the time signal of the zero-order symmetrical mode Lamb Wave which had propagated in the aluminum lamina for a distance. The change of Waveform with the propagation distance in different frequency bands is analyzed. The simulation result indicated the method could effectively compute the time Waveform of single-mode Lamb Wave. The method could offer the theoretical foundation for the application of symmetrical Lamb Wave measuring technique in the time domain.
Yung-yu Chen - One of the best experts on this subject based on the ideXlab platform.
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Dispersion characteristics of high-order Lamb Wave modes in an AlN/3C-SiC layered plate
2012 IEEE International Ultrasonics Symposium, 2012Co-Authors: Chih-ming Lin, Debbie G. Senesky, Yung-yu Chen, Viktoria V Felmetsger, Albert P. PisanoAbstract:A new propagation layered media composed of a piezoelectric thin film and a substrate plate is studied in this work. The displacement profiles, phase velocities, and electromechanical coupling coefficients of Lamb Wave modes are theoretically investigated for the c-axis oriented AlN films on cubic silicon carbide (3C-SiC) plates. Due to the different material properties of the AlN and 3C-SiC layers, the displacement profiles of Lamb Wave modes are not simply antisymmetric or symmetric with respect to the neutral axis. According to the displacement profiles, the plate acoustic Wave modes in the layered plate are classified as quasi-Lamb Wave modes. Some high-order quasi-Lamb Wave modes in the layered plate have larger electromechanical couplings than the corresponding Lamb Wave modes in an AlN thin plate. In addition, the third quasi-symmetric (QS3) Lamb Wave mode exhibits a low motional impedance (Rm) of 91 ohm and a high quality factor (Q) up to 5510 at a frequency (fs) of 2.92 GHz, resulting in the highest fs·Q product, 1.61×1013 Hz, among suspended piezoelectric thin film resonators reported to date.
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high q aluminum nitride Lamb Wave resonators with biconvex edges
Applied Physics Letters, 2011Co-Authors: Yung-yu Chen, Debbie G. Senesky, Albert P. PisanoAbstract:A Lamb Wave resonator utilizing an aluminum nitride (AlN) plate with biconvex edges to enhance the quality factor (Q) is demonstrated. The simulation results based on finite element analysis verify that the use of the biconvex edges, instead of the conventional flat edges, can efficiently confine mechanical energy in the AlN Lamb Wave resonator. Specifically, the measured frequency response of a 491.8-MHz AlN Lamb Wave resonator with biconvex edges yields a Q of 3280 which represents a 2.6× enhancement in Q over a 517.9-MHz Lamb Wave resonator on the same AlN plate but with the suspended flat edges.
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theoretical investigation of Lamb Wave characteristics in aln 3c sic composite membranes
Applied Physics Letters, 2010Co-Authors: Chih-ming Lin, Yung-yu Chen, Albert P. PisanoAbstract:Cubic silicon carbide (3C–SiC) layer can provide advantages of high frequency and high quality factor for Lamb Wave devices due to the superior properties of high acoustic velocity and low acoustic loss. In this study, Lamb Wave propagation characteristics in composite membranes consisting of a c-axis oriented aluminum nitride (AlN) film and an epitaxial 3C–SiC (100) layer are investigated by theoretical calculation. The lowest symmetric mode Lamb Wave propagating along the [011] direction exhibits a phase velocity higher than 10 000 m/s and an electromechanical coupling coefficient above 2% in the AlN/3C–SiC multilayered membranes.
