Language：English   Publishing type：Research paper (international conference proceedings)   Participation form：Joint(The main charge)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IOP Conference Series: Materials Science and Engineering  

The purpose of this research is to investigate an appropriate design of the sliced cartilage used for the reconstruction of the tympanic membrane (TM). A great number of people are suffering from TM perforation caused by diseases or accidents. A surgical procedure, called cartilage myringoplasty, can save the people from hearing loss by replacing the damaged part of the membrane with thin-sliced cartilage. In this research, as the first step of designing the sliced cartilage, we established a three-dimensional finite element model of the human ear for numerical analysis. The ear model consists of the middle ear (TM, ossicular chain, ligaments, muscle), and inner ear cochlea. The joints between ear bones were also modelled with softer tissues. The analysis result of the frequency response shows a good correspondence with measurement results reported by other researchers. Then, using the numerical model, we investigated the optimal thickness of the cartilage plate. The TM was cut at the bottom position with a size of about 40% of TM and filled by cartilage plate with the thickness of 0.1mm to 0.7mm. Comparing with the frequency response of the healthy ear, we found that the optimal thickness of the plate is different in a various frequency range. The reason is considered as the difference of material properties between the membrane and the cartilage. Finally, to evaluate the performance of repaired models in all frequency range, we proposed an equation of matching rate as the evaluation equation. The results show that 0.5mm cartilage plate model shows a better performance at peak response area (600Hz-1kHz), and 0.3mm. cartilage plate model shows better average performance in the total frequency range.

DOI： 10.1088/1757-899X/886/1/012045

Scopus

Other Link： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85090267545&origin=inward

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IOP Conference Series: Materials Science and Engineering  

This research concerns the detection method of contact-type failure based on nonlinear wave modulation utilizing ultrasonic vibration driven by self-excitation. When the structure is vibrating by environmental force or forced excitation, the contact area is fluctuated by vibration. In this condition, the vibration transfer characteristics of ultrasonic vibration have fluctuated in synchronization with vibration (non-linear wave modulation). The detection method based on non-linear wave modulation can detect contact-type failure. In this paper, the novel detection method based on nonlinear wave modulation is presented. Firstly, the self-excitation method using local feedback control is introduced. Local feedback control can oscillate at the natural frequency automatically. Secondly, the concept of a novel detection method is introduced. When the structure with contact-type failure is vibrating, the frequency of the ultrasonic vibration excited by local feedback control will fluctuate in synchronization with natural frequency fluctuation. To explain the detection method, non-linear wave modulation is expressed 1 degree of freedom model. In this model, the local stiffness fluctuation is modelled by the spring element of which spring coefficient is fluctuated in synchronization with structural vibration. We regard the transfer function of this model as a linear time-varying system. The amplitude of the fluctuation of natural frequency caused by stiffness fluctuation can be the novel index of failure level. Lastly, the result of the experiment using the uniform beam specimen is shown. From the relationship between forcing pressure of the contact-type failure and the amplitude of the frequency modulation, it is proved that the novel index is associated with failure level.

DOI： 10.1088/1757-899X/886/1/012032

Scopus

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Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Nagoya University  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：University of Toyama  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：University of Toyama  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Online