The University of Tokyo · Engineering
Professor Fengming Yu's research lab specializes in advanced structural health monitoring (SHM) and nondestructive evaluation (NDE) techniques for high-performance composite materials, particularly under extreme environments such as elevated temperatures. The lab focuses on developing fiber-optic sensing technologies—especially phase-shifted fiber Bragg grating (PS-FBG) sensors—combined with ultrasonic and acoustic emission (AE) methods for real-time damage detection and characterization in heat-resistant composites like ceramic matrix composites and carbon fiber-reinforced plastics (CFRPs). Key innovations include remote AE sensing using optical fibers as waveguides, enabling accurate signal detection from high-temperature regions to room-temperature sensors, and integrating laser ultrasonic visualization for enhanced damage localization and mode identification. The lab also explores the fundamental mechanisms of material behavior during thermal and mechanical loading, supporting the development of reliable SHM systems for aerospace and energy applications.
Figures are computed from collected data and may differ slightly.
Recently, the authors have proposed a remote acoustic emission (AE) measurement configuration using a sensitive fiber-optic Bragg grating (FBG) sensor. In the configuration, the FBG sensor was remotely bonded on a plate, and an optical fiber was used as the waveguide to propagate AE waves from the adhesive point to the sensor. The previous work (Yu et al., Smart Materials and Structures 25 (10), 105,033 (2016)) has clarified the sensing principle behind the special remote measurement system that
Acoustic emission (AE) detection functioning at high temperatures could clarify the damage process in high heat-resistant composites. To achieve the high-temperature AE detection, a remote AE measurement based on a phase-shifted fiber Bragg grating (PS-FBG) sensor with a high sensitivity over a broad bandwidth was proposed. The common optical fibers were made from glass with good heat resistance. Hence, in this method, optical fiber was used as the waveguide to propagate the AE in the composite
In this research, we attempt to establish a reliable structural health monitoring technique for composite materials by combining phase-shifted fiber-optic Bragg grating sensing with the laser ultrasonic visualization technology. In the first part of this article, a novel cross-adhesion configuration is designed to resolve the directionality problem of the phase-shifted fiber-optic Bragg grating ultrasonic sensing. In the adhesion configuration, Lamb waves are guided by an orthogonally bonded opt
In this study, a phase-shifted fiber Bragg grating sensor was employed for acoustic emission detection in cross-ply carbon fiber–reinforced plastic laminates. First, we evaluated the response of the phase-shifted fiber Bragg grating sensor to a simulated acoustic emission source using a pencil lead breakage test. The existing modes of Lamb waves were observed, and their relations to the acoustic emission source orientation were investigated using a modal acoustic emission method for discriminati
Heat-resistant composites, such as ceramic matrix composites and heat-resistant carbon fiber reinforced plastics (CFRPs), are expected to be used for aircraft engine parts. The development of reliable heat-resistant composite materials requires the use of nondestructive test techniques for evaluating the progression of damage during material testing at elevated temperatures. Furthermore, structural health monitoring (SHM) technologies that operate under harsh environments are expected to be real
In order to explore the characteristic of calcium content variation and distribution in different tissues,and the mechanism of higher calcium content in Chinese dwarf cherry(Prunus humilis) fruit,different kinds of calcium contents,which were extracted by sequential extraction procedure,were analyzed during the fruit development.The results showed that the accumulation of calcium in fruits appeared in two periods,one was the mitotic period of young fruits,which appeared in 45 d after flowering a
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To improve the dynamic and steady-state control performance of permanent magnet synchronous motors under the three-vector model predictive current control method, this study proposes a switching current predictive control method based on the exponential moving average algorithm, which evaluates the magnitude of the change of the q-axis current slope in real time to discriminate the motor’s operating conditions and selects the optimal control method for different operating conditions. Meanwhile,
Because of the stable material property of optical fiber up to 1000℃, fiber-optic Bragg grating (FBG) sensor is considered as one of possible ultrasonic sensors used at ultrahigh temperature. However, disappearance of reflectivity of a normal FBG in the high temperature above 900℃ makes the ultrasonic detection impossible. In order to detect ultrasonic wave under high temperature environments, we conducted an anneal heat treatment to produce a regenerated fiber Bragg grating (RFBG) sensor. Becau
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