The University of Tokyo

Subaru Corporation

Yamaha Hatsudoki Kabushiki Kaisha

Fuji Jukogyo Kabushiki Kaisha

Yoji Okabe

Hideki Soejima

Qi Wu

Osamu Saito

Koji Omichi

Shota Tezuka

Peiwen Deng

Ryujiro Nomura

Taku Kondoh

Akihiro Chiba

A detector that detects an internal state of a plate-shaped object including a fiber-reinforced resin. The detector includes an exciter that applies, to a surface of the object, ultrasonic vibrations of Lamb waves, in a selected frequency range where only a zero-order fundamental wave symmetric mode and a zero-order fundamental wave asymmetric mode of the Lamb waves appear, a vibration detector that detects the applied ultrasonic vibrations propagating in the object, and an internal state estimation calculator that estimates the internal state of the object, by obtaining a propagation time of the ultrasonic vibrations propagating in the object corresponding to each frequency of the Lamb waves, based on the detection result of the vibration detector, estimating the internal state based on a delay time of the propagation time relative to a reference propagation time of the object for each frequency in the selected frequency range, and outputting the estimated internal state.

Internal state detector and vehicle

The object of the invention is to provide a damage diagnostic system that uses a damage detection system that obtains propagation intensity distribution data, which is expanded in the two dimensions frequency and propagation time, by converting the output value from an oscillation detection sensor that was obtained when oscillation is performed by an oscillator, and for one mode or two or more modes that are selected from the fundamental mode and higher mode of Lamb waves, obtains certain characteristic values from the data, for example three indices, which are the slope of the mode dispersion of the A1 mode (rate of change of the propagation time with respect to the frequency), the amount of decrease in the propagation time of the A1 mode, and the amount of increase in the propagation time of the S0 and S1 modes, and outputs the measurement results. The measurement results are displayed on a display device.

System and method for damage diagnosis

A vibration detection apparatus includes a ring laser resonator, a fiber Bragg grating and a detection system. The ring laser resonator generates a laser beam propagating a ring shaped optical path. The fiber Bragg grating is disposed in the ring laser resonator such that the laser beam enters the grating, and has a transmittance distribution characteristic of transmitted light in a wavelength direction, which changes in accordance with vibration of an object. The detection system detects the vibration based on the transmitted light through the fiber Bragg grating.

Vibration detection apparatus and vibration detection method

Displacement measuring device with light irradiation system, first and second FBGs and detecting system. The first FBG has first transmittance distribution or first reflectance distribution. The second FBG has second transmittance distribution or second reflectance distribution. The detecting system detects light passed through the first and second FBGs of which at least one of the first transmittance distribution and the second transmittance distribution changes in a wavelength direction with a change amount different from that of the other, according to a displacement amount of an object, or amplitude of the light passed through the first and the second FBGs of which at least one of the first reflectance distribution and the second reflectance distribution changes in the wavelength direction with a change amount different from that of the other, according to the displacement amount of the object, and acquires an index to indicate the displacement amount based on the amplitude.

Displacement measuring device and displacement measuring method

Growing community of inventors

Tokyo, Japan

Yoji Okabe