We propose an advanced digital twin of artifact systems (DTAS) in which physical and numerical models of structural materials at several time scales and length scales are constructed and integrated, while monitoring and inspection data of structural materials are used as input parameters. As DTAS can reproduce the current state of structural materials and predict their degradation through their service life, it can improve the resilience and give plasticity to artifact systems. A portion of the results rela...
英字タイトル:
A digital-twin of artifact systems by synthesizing multiscale modeling and monitoring

We have developed a newly sensing technique by which we can measure strain or temperature along an optical fiber with the high spa tial resolution of less than 1 mm. This fiber-optic distributed sensing technique is based on optical frequency domain reflectomet ry and it can map strain or temperature profiles along fiber Bragg grating. In this paper, the principle of this technique, distri buted strain sensing with the high spatial resolution and the applications to strain measurements of welded joints are...
英字タイトル:
Study on Fiber-Optic Distributed Sensing Technique with High Spatial Resolution

FOD (Fiber Optical Doppler) sensor, that can measure elastic wave in wide-band frequency, has been developed, which utilizes Laser Doppler effect within an optical fiber. In particular, FOD sensor can detect Acoustic Emission (AE), which is a useful parameter to monitor in-situ damage at various industrial equipments. AE is caused mainly by very initial micro-crack within a structural material due to over-stress, material-aging, etc. When taking advantage of fiber-optics, that are long signal transmi...
英字タイトル:
Condition Monitoring and Damage Screening by Fiber-optic AE Sensor

FOD (Fiber Optical Doppler) sensor, that can measure elastic wave in wide-band frequency, has been inve nted and developed, which utilizes Laser Doppler effect within an optical fiber. In particular, FOD sen sor can detect acoustic emission (AE), which is sometimes very useful parameter to monitor in-situ dama ge at various equipments. Report herein is its measurement principle and its application for field use....
英字タイトル:
Condition Monitoring and Damage Screening by Fiber-optic AE Sensor

In many cases, the function loss by fatigue and fracture is considered as the ultimate condition of the artificial structure. While various CAE technologies have been developed, a high-precision calculation algorithm has been developed for material damage during repeated loading, which is assumed to be difficult to describe in a digital twin in a computer virtual space. To make high precision evaluation, material damage from cyclic pre-strain is investigated. Then, material damage depends on not only equiva...
英字タイトル:
Construction of a meso-space scale model for constructing a high-precision damage estimation rule