Ultrasonic transducer arrays are extensively used for the nondestructive evaluation of materials for aerospace and other applications. However, their use with composites requires some technique development because of reflections at the layer boundaries and the effects of attenuation. When used in full matrix capture mode, algorithms such as the total focusing method (TFM) must be applied to obtain the image. In composite materials, improvement to the algorithm is required to include the effects of material anisotropy (affecting wave speed) and optimum aperture limits to optimize the signal-to-noise ratio and location detection for a defect in the material. This paper presents simulations of the ultrasonic array signals in multilayer anisotropic materials with and without a simulated defect. A kernel model for plane wave propagation in the material is combined with an angular spectrum decomposition (for finite transducer elements) and transducer frequency response, to model the full array signals. Inclusion of the defect is through its far-field scattering response. The model facilitates the study of imaging algorithm development by identification of the effects of anisotropy, signal-to-noise ratio, and aperture limit. An analytical method for the calculation of the effective group velocity in the composite at low frequency is demonstrated, permitting rapid calculation of time delay laws in practice.
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http://dx.doi.org/10.1109/TUFFC.2013.2778 | DOI Listing |
Molecules
January 2025
Department of Agriculture, Food, Environment and Forestry (DAGRI), University of Florence, Sesto Fiorentino, 50019 Florence, Italy.
L., commonly known as the mastic tree or lentisk, is a woody Mediterranean plant revered for its ecological relevance as well as for its extensive ethnobotanical heritage. Historically, the fruits and the resin of have been widely utilized in traditional medicine, underscoring its important role in local healing practices.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
School of Control Science and Engineering, Shandong University, Ji'nan 250061, China.
Carbon fiber reinforced plastics inevitably develop defects such as delamination, inclusions, and impacts during manufacturing and usage, which can adversely affect their performance. Ultrasonic phased array inspection is the most effective method for conducting nondestructive testing to ensure their quality. However, the diversity of defects within carbon fiber reinforced plastics makes it challenging for the current ultrasonic phased array inspection techniques to accurately identify these defects.
View Article and Find Full Text PDFMicromachines (Basel)
January 2025
College of Mechanical & Electrical Engineering, Central South University, Changsha 410083, China.
In the health monitoring and safety assessments of concrete structures, ultrasonic non-destructive testing (NDT) technology has become an indispensable tool due to its non-destructive nature, efficiency, and precision. However, when used in inspecting irregular concrete surfaces, traditional planar ultrasonic transducers often encounter energy loss and signal attenuation induced by poor interface coupling, which significantly reduces the accuracy and reliability of the test results. To address this problem, this article proposes a point-contact dry coupling ultrasonic transducer solution, which enables efficient acquisition of ultrasonic signals within concrete without the need for couplants.
View Article and Find Full Text PDFMicromachines (Basel)
December 2024
State Key Laboratory of Precision Measurements Technology and Instrument, Tianjin University, Tianjin 300072, China.
Piezoelectric micromachined ultrasonic transducers (PMUTs) show considerable promise for application in ultrasound imaging, but the limited bandwidth of the traditional PMUTs largely affects the imaging quality. This paper focuses on how to arrange cells with different frequencies to maximize the bandwidth and proposes a multi-frequency PMUT (MF-PMUT) linear array. Seven cells with gradually changing frequencies are arranged in a monotonic trend to form a unit, and 32 units are distributed across four lines, forming one element.
View Article and Find Full Text PDFAppl Phys Lett
January 2025
Department of Biomedical Engineering, University of California, Irvine, California 92617, USA.
Electroacoustic imaging is an imaging modality used to detect electric field energy distribution during electroporation, offering valuable guidance for clinical procedures, particularly in deep tissues. Traditionally, single-element piezoelectric transducers or arrays have been employed for this purpose. However, these piezoelectric sensors are sensitive to electromagnetic interference and require physical contact with the sample through a coupling medium, raising concerns for both clinical and preclinical applications.
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