Impact Damage Detection of FRP using Michelson Interferometric Fiber-Optic Sensors

Fiber optic sensors become very popular for structural testing and monitoring in civil engineering nowadays, due to its advantage of high resolution and environment durability. In this paper, long-gauge fiber optic bragg grating sensors will be introduced. Structural damage detection stratagem using the micro-strain mode will be studied. Then its application to a structural testing and monitoring for a real long span truss bridge will be discussed in detail. In the testing, 23 long-gauge fiber optic bragg grating sensors were deployed on the mid span of the bridge. Testing were made under conditions either there is train on the bridge or no train on it. Corresponding dynamic characteristics were analyzed and discussed. Results of the testing show that long-gauge fiber optic sensors can work well for structural testing and also damage detection for truss bridges.

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Local and Global Approaches for Damage Detection in Composite Structures by Fiber Optic Sensors

10.20944/preprints201802.0110.v1 ◽

2018 ◽

Author(s):

Alfredo Guemes ◽

Antonio Fernandez- Lopez ◽

Patricia F. Diaz-Maroto ◽

Angel Lozano ◽

Julián Sierra-Pérez

Keyword(s):

Damage Detection ◽

Composite Structures ◽

Fiber Optic ◽

A Priori ◽

Fiber Optic Sensors ◽

Network Density ◽

Strain Measurements ◽

Damage Location ◽

Local Technique ◽

External Loads

Fiber optic sensors cannot measure damage; for getting information about damage from strain measurements, additional strategies are needed, and several alternatives have been proposed. This paper discuss two independent concepts: the first one is based on detecting the new strains appearing around a damage spot; the structure does not need to be under loads; the technique is very robust, damage detectability is high, but it requires sensors to be located very close to the damage, so it is a local technique. The second approach offers a wider coverage of the structure, it is based on identifying the changes caused by the damage on the strains field in the whole structure for similar external loads. Damage location does not need to be known a priori, detectability is dependent upon the sensors network density, damage size and the external loads. Examples of application to real structures are given.

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Fiber Optic Sensors for Damage Detection in Composite Materials

ASME 1997 Turbo Asia Conference ◽

10.1115/97-aa-067 ◽

1997 ◽

Author(s):

Anand Asundi

Keyword(s):

Composite Materials ◽

Damage Detection ◽

Monitoring System ◽

Fiber Optic ◽

Fiber Optic Sensors ◽

Design Rules ◽

Interferometric Sensors ◽

On Line ◽

Proper Design

An absence of proper design rules has limited the application of composite materials to specific areas. However, within these application areas there is still a need to regular monitor the component resulting in significant downtime and loss of revenue. To overcome this it is proposed to have an on-line monitoring system capable of global checking of the component. Fiber optic polarimetric sensors are chosen in this study to globally characterize the health of a component. Polarimetric sensors have better sensitivity than intensity sensors and at the same time are more rugged than interferometric sensors. In this study, the effect of debonds and fiber breakages are investigated in composite bend specimens.

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