Stress Analysis of Composite Material Embedded with Optical Fiber Sensor Subjected to In-Plane Shear

Optical fiber sensor with small size, light weight and immunity to electromagnetic interference can be embedded and integrated into the host material to form an ideally smart structure system. One must recognize that optical fibers are foreign entities to the host structure, therefore will induce high stress state in the vicinity of the embedded sensor irrespective of the small size of the fiber. To address this concern, present paper focuses the attention on constituent interaction between the optical fiber, coating, matrix and host material. An analytical model to predict the stress fields in the vicinity of the embedded optical fiber is presented. The theoretical development is based on the four concentric cylinders model which represents the optical fiber, protective coating, matrix and host material, respectively. The host material is considered to be a composite with reinforced fiber parallel to the optical fiber. In this investigation, the host structure is subjected to in-plane shear loading. The effects of the coating and host material on the stress distribution in the vicinity of the embedded optical fiber are presented through a parametric study.

Download Full-text

Stress Analysis of Composite Material Embedded with Optical Fiber Sensor

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.326-328.59 ◽

2006 ◽

Vol 326-328 ◽

pp. 59-62

Author(s):

Shiuh Chuan Her ◽

Bo Ren Yao

Keyword(s):

Optical Fiber ◽

Optical Fibers ◽

Electromagnetic Interference ◽

Optical Fiber Sensor ◽

Local Stress ◽

Smart Structure ◽

Fiber Optic Sensor ◽

Host Material ◽

Concentric Cylinders ◽

Host Structure

Fiber optic sensor with small size, light weight and immunity to electromagnetic interference can be embedded and integrated into the host material to form a smart structure system. One must recognize that optical fibers are foreign entities to the host structure, therefore will alter the stress state in the vicinity of the embedded sensor irrespective of the small size of the fiber. This is a result of the material and geometric discontinuity introduced by the embedded optical fiber. In this study, the local stress fields in the vicinity of the embedded fiber are examined. The host material is considered to be a composite with reinforced fiber parallel to the optical fiber. The geometry in the vicinity of the embedded fiber is modeled by four concentric cylinders which represent the optical fiber, protective coating, resin and host material, respectively. In this investigation, the host structure is subjected to longitudinal normal stress and transverse hydro-static stress. The effects of the coating and host material on the stress distribution in the vicinity of the embedded optical fiber are presented through a parametric study.

Download Full-text

Strain Transfer From the Host Structure to Optical Fiber Sensor

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.201-203.2419 ◽

2011 ◽

Vol 201-203 ◽

pp. 2419-2422

Author(s):

Shiuh Chuan Her ◽

Chang Yu Tsai

Keyword(s):

Optical Fiber ◽

Protective Coating ◽

Electromagnetic Interference ◽

Optical Fiber Sensor ◽

Adhesive Layer ◽

Small Dimension ◽

Host Material ◽

Fiber Sensor ◽

Strain Transfer ◽

Host Structure

Optical fiber sensors with light weight, small dimension and immunity to electromagnetic interference are considered as a superior structural health monitoring device. It is well known that the strain transfer from the host structure to the optical fiber sensor is dependent on the bonding characteristics such as adhesive layer, protective coating and host material. In this investigation, a theoretical model with three concentric cylinders represented optical fiber, protective coating, and host material, respectively, is proposed to determine the strain in the optical fiber sensor induced by the host structure. The theoretical predictions are validated with the numerical analysis using the finite element method. The effect of host material on the strain transferred is presented through a parametric study.

Download Full-text

Stress Analysis of Optical Fiber Sensor Embedded Composite Subjected to Tri-Axial Normal Loadings

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.364-366.998 ◽

2007 ◽

Vol 364-366 ◽

pp. 998-1002

Author(s):

Shiuh Chuan Her ◽

Bo Ren Yao

Keyword(s):

Optical Fiber ◽

Optical Fiber Sensor ◽

Smart Structure ◽

Host Material ◽

Theoretical Development ◽

Fiber Sensors ◽

Fiber Coating ◽

Concentric Cylinders ◽

Wide Range ◽

Coating Matrix

Optical fiber sensors have been developed during the past decade to measure a wide range of physical quantities such as strain and temperature. The perturbation of the surrounding field in the host due to the presence of the optical sensor will not only alter the values of the field variables being measured, but may also affect the integrity of the host. Resulting degradations can compromise the accuracy and long term reliability of the smart structure. The present paper focuses the attention on constitutent interaction between the optical fiber, coating, matrix and host material. An analytical model to predict the stress fields in the vicinity of the embedded optical fiber was derived. The theoretical development was based on the four concentric cylinders models which represented the optical fiber, protective coating, matrix and host material, respectively. The interfaces between each constitutent were assumed to be perfect bonds, so that the tractions and displacements were continuous across each interface. In this investigation, the host structure was subjected to three normal loadings along the axial directions. Numerical examples were presented to investigate the effects of the coating and host material on the stress distribution in the vicinity of the embedded optical fiber.

Download Full-text

A Multiplexed Optical Fiber Sensor System For Distributed Measurement Of Structural Strains

MRS Proceedings ◽

10.1557/proc-503-119 ◽

1997 ◽

Vol 503 ◽

Author(s):

F. Ansari ◽

Z. Chen ◽

Q. Li

Keyword(s):

Optical Fiber ◽

Optical Switch ◽

Optical Fiber Sensor ◽

Fiber Material ◽

Smart Structure ◽

Sensor System ◽

Fiber Sensor ◽

Fiber Sensors ◽

Large Structures ◽

Distributed Measurement

ABSTRACTStructurally integrated optical fiber sensors form the basis for smart structure technology. Over the past decade a variety of sensor configurations have been developed for measurement of strains and deformations in structures. Strains and deformations alter the refractive index and the geometry of the optical fiber material. These changes perturb the intensity, phase, and polarization of the light-wave propagating along the probing fiber. The optical perturbations are detected for the determination of strain. The research presented here describes the development of a new optical fiber sensor system for measurement of structural strains based on white light interferometry. An optical switch provides for multiplexing of strain signals from various locations in the structure. Redundant Bragg grating type fiber optic sensors as well as strain gauges were employed for comparison and verification of strain signals as measured by the new system. The system provides capability for distributed sensing of strains in large structures.

Download Full-text

Strain Analysis of Surface Bonded Optical Fiber Sensors

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.121-126.4166 ◽

2011 ◽

Vol 121-126 ◽

pp. 4166-4170

Author(s):

Shiuh Chuan Her ◽

Chang Yu Tsai

Keyword(s):

Optical Fiber ◽

Electromagnetic Interference ◽

Optical Fiber Sensor ◽

Strain Analysis ◽

Adhesive Layer ◽

Optical Fiber Sensors ◽

Fiber Sensor ◽

Fiber Sensors ◽

Theoretical Predictions ◽

Host Structure

Optical fiber sensors with light weight, small size and immunity to electromagnetic interference have been found to be a promising device for use in the development of smart structures. It is well known that the strain transfer from the host structure to the optical fiber sensor is dependent on the bonding characteristics such as adhesive layer and bonded length. In this investigation, the optical fiber sensor is surface bonded on the host structure. A theoretical model consisting of the optical fiber, adhesive layer and host material, is proposed to determine the strain in the optical fiber sensor induced by the host structure. The theoretical predictions were validated with the numerical analysis using the finite element method.

Download Full-text

Strain Analysis of an Embedded Optical Fiber Sensor

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.467-469.279 ◽

2011 ◽

Vol 467-469 ◽

pp. 279-282

Author(s):

Shiuh Chuan Her ◽

Chang Yu Tsai

Keyword(s):

Optical Fiber ◽

Electromagnetic Interference ◽

Optical Fiber Sensor ◽

Strain Analysis ◽

Adhesive Layer ◽

Small Dimension ◽

Host Material ◽

Fiber Sensor ◽

Fiber Sensors ◽

Theoretical Predictions

Optical fiber sensors with light weight, small dimension and immunity to electromagnetic interference are widely used in structural health monitoring device. In this investigation, a theoretical model of the strain transferred from the host material to the embedded optical fiber is developed to reveal the differential strains between the optical fiber sensor and host material. The theoretical predictions are validated with the numerical analysis using the finite element method. The percentage of strain in the host material actually transferred to the optical fiber is dependent on the bonding characteristics such as adhesive layer, protective coating and host material. Parametric study shows that the larger of the host material the more strain is transferred to the optical fiber.

Download Full-text

Optical Fiber Sensor for Smart Structure Monitoring

10.1063/1.3469618 ◽

2010 ◽

Cited By ~ 1

Author(s):

N. Jannah Muhd-Satar ◽

M. Kamil Abd-Rahman ◽

A. K. Yahya ◽

Shah Alam

Keyword(s):

Optical Fiber ◽

Optical Fiber Sensor ◽

Smart Structure ◽

Fiber Sensor ◽

Structure Monitoring

Download Full-text

Stress Analysis of a Resin Pocket Embedded in Laminated Composites for an Optical Fiber Sensor

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.419-420.293 ◽

2009 ◽

Vol 419-420 ◽

pp. 293-296 ◽

Cited By ~ 1

Author(s):

Shiuh Chuan Her ◽

Bo Ren Yao ◽

Shien Chin Lan ◽

Chun Yen Liu

Keyword(s):

Stress Concentration ◽

Optical Fiber ◽

Optical Sensors ◽

Optical Sensor ◽

Laminated Composites ◽

Optical Fiber Sensor ◽

High Stress ◽

Small Diameter ◽

Fiber Sensor ◽

Resin Pocket

Optical fiber sensors have a number of advantages over conventional electronic sensors such as light weight, small diameter and immunity to electromagnetic interference. Despite all the advantages of optical sensors, one must recognize that optical fibers are foreign entities to the host structure, therefore will induce stress concentration in the vicinity of the embedded sensor. As an optical sensor is embedded between plies, a lenticular resin pocket exists in the composite plies. The resin pocket acts as a crack-like region, and can form the site of the initiation of the delamination under mechanical loads. In this investigation, the geometry of the lenticular resin pocket around the optical sensor is derived basing on the principal of minimum potential energy. It shows that the geometry of the resin pocket is dependent on the stiffness of the plies, the stacking sequence, the diameter of the optical fiber and the curing pressure. The stress distributions in the resin pocket and in the laminated composites are obtained by using the finite element method. The numerical results demonstrate that the stress increases rapidly in the vicinity of the optical fiber sensor, causing a high stress concentration factor. The high stress field may produce delamination and fracture in the composite.

Download Full-text