@article{prabhugoud_peters_2007, title={Finite element analysis of multi-axis strain sensitivities of Bragg gratings in PM fibers}, volume={18}, ISSN={["1045-389X"]}, DOI={10.1177/1045389X06074680}, abstractNote={ This article presents a numerical analysis of the sensitivity of fiber Bragg grating (FBG) sensors written into polarization maintaining fibers to transverse and thermal loading. These sensors are typically applied for the measurement of multiple strain components for the monitoring of civil structures. The finite element analysis includes both the optical and mechanical variations in the optical fiber. Five fiber types typically used in FBG sensors (elliptical core, D-fiber, elliptical core SAP, Bow-Tie, and Panda) are compared. It is shown that when only the fiber geometry is considered while the material parameters are approximately the same, the D-fiber demonstrates the highest sensitivity to transverse loading. In addition, it is shown that reducing the fiber cladding diameter significantly improves the sensitivities of the FBG sensor to transverse loads. All fiber types exhibit approximately the same sensitivity to thermal loading. }, number={8}, journal={JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES}, author={Prabhugoud, Mohanraj and Peters, Kara}, year={2007}, month={Aug}, pages={861–873} }
 @article{pearson_zikry_prabhugoud_peters_2007, title={Global-local assessment of low-velocity impact damage in woven composites}, volume={41}, ISSN={["1530-793X"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-35448962064&partnerID=MN8TOARS}, DOI={10.1177/0021998307078734}, abstractNote={ Global measurements from low-velocity impact experiments and local strain measurements from embedded and surface mounted optical fiber Bragg grating (FBG) sensors were used to obtain failure maps for two- and three dimensional woven composites. These maps delineated five distinct regimes spanning behavior from initial impact to complete penetration. Sensor and host damage were separated by signal intensity and the evolution of Bragg peaks due to repeated impact loads. The results indicate that a local-global framework can be used to monitor damage progression in different host materials, and hence it can be potentially used to mitigate damage. }, number={23}, journal={JOURNAL OF COMPOSITE MATERIALS}, author={Pearson, J. D. and Zikry, M. A. and Prabhugoud, M. and Peters, K.}, year={2007}, month={Dec}, pages={2759–2783} }
 @article{prabhugoud_peters_pearson_zikry_2007, title={Independent measurement of strain and sensor failure features in Bragg grating sensors through multiple mode coupling}, volume={135}, ISSN={["0924-4247"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-34047170478&partnerID=MN8TOARS}, DOI={10.1016/j.sna.2006.08.021}, abstractNote={This article presents the interrelated measurements of Bragg reflection, cladding and radiation modes to obtain the applied strain and integrity of a short period Bragg grating sensor. While the Bragg reflection is known to be sensitive to applied strain, the relative strength of the cladding and radiation mode coupling is shown to be sensitive to damage such as debonding from the host structure. Furthermore, the length of the Bragg grating debonded from the surrounding medium is quantitatively related to the coupling to continuum radiation modes from the core mode. While the sensitivity of the radiation mode coupling to microcracking in the optical fiber is shown to be relatively low, maximum intensity measurements provide sufficient information on local fractures of the optical fiber. These results provide intelligent self-diagnostic capabilities within the Bragg grating sensor without additional measurements, and also permit the separate identification of sensor failure from the failure of the host structure.}, number={2}, journal={SENSORS AND ACTUATORS A-PHYSICAL}, author={Prabhugoud, Mohanraj and Peters, Kara and Pearson, James and Zikry, Mohammed A.}, year={2007}, month={Apr}, pages={433–442} }
 @article{pearson_zikry_prabhugoud_peters_2007, title={Measurement of low velocity and quasi-static failure modes in PMMA}, volume={28}, ISSN={["0272-8397"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-34250820545&partnerID=MN8TOARS}, DOI={10.1002/pc.20287}, abstractNote={Abstract}, number={3}, journal={POLYMER COMPOSITES}, author={Pearson, J. D. and Zikry, M. A. and Prabhugoud, M. and Peters, K.}, year={2007}, month={Jun}, pages={381–391} }
 @article{prabhugoud_peters_2006, title={Finite element model for embedded fiber Bragg grating sensor}, volume={15}, ISSN={["1361-665X"]}, DOI={10.1088/0964-1726/15/2/038}, abstractNote={This paper presents an integrated formulation for the calculation of the spectral response of a fiber Bragg grating sensor embedded in a host material system, as a function of the loading applied to the host structure. In particular, the calculation of the transverse strain sensitivity of a fiber Bragg grating sensor through the calculation of the change in effective index (or indices) of refraction of the fiber cross-section due to the applied load is presented in detail. For the calculation of the fiber propagation constants, a two-step finite element formulation is used incorporating the optical, geometric and material properties of the cross-section. Once the propagation constants and principal optical axes are known along the fiber, a modified transfer matrix method is applied to calculate the spectral response of the FBG. It is shown that the FE formulation yields close agreement with previous methods for benchmark diametrical compression cases. However, the current method provides the potential to evaluate the effects of high strain gradients across the optical fiber core present in some loading applications.}, number={2}, journal={SMART MATERIALS AND STRUCTURES}, author={Prabhugoud, M and Peters, K}, year={2006}, month={Apr}, pages={550–562} }
 @article{prabhugoud_peters_2004, title={Modified transfer matrix formulation for Bragg grating strain sensors}, volume={22}, ISSN={["1558-2213"]}, DOI={10.1109/JLT.2004.833281}, abstractNote={This paper presents a formulation for the application of the transfer matrix method to Bragg grating strain sensors. A modified T-matrix representation is detailed for the sensor problem based on an effective period derived from the coupling coefficients. This modified T-matrix formulation is shown to converge to the coupled-mode equations solution for a large number of grating segments, even in the presence of significant strain gradients. Several numerical examples are presented to demonstrate the importance of inclusion of the strain gradient in the calculation. In addition, the current formulation is validated by application to previously published experimental data.}, number={10}, journal={JOURNAL OF LIGHTWAVE TECHNOLOGY}, author={Prabhugoud, M and Peters, K}, year={2004}, month={Oct}, pages={2302–2309} }
 @article{prabhugoud_peters_2003, title={Efficient simulation of Bragg grating sensors for implementation to damage identification in composites}, volume={12}, ISSN={["1361-665X"]}, DOI={10.1088/0964-1726/12/6/008}, abstractNote={A computationally efficient method is proposed to interpret optical fiber sensor data collected from Bragg grating sensors embedded in composites. The method divides the composite into remote field and critical field regions with respect to any developed damage. These regions are defined via non-uniformities in the sensor response. The remote field response is treated via an optimal shear-lag theory first presented by Mendels and Nairn. This formulation provides a rapid solution of the average fiber axial stress at the location of each sensor. The critical field region is modeled via a finite element sensor model including the effects of multi-axis loading on the sensor and an optical loss due to local fiber curvature. The response of the Bragg grating sensor to the effects of axial, bending and shear loading are simulated for inclusion in the model. The bending loss response as a function of fiber curvature is experimentally measured. The application of this method is demonstrated through a numerical example, simulating the response of sensors embedded in a lamina to the presence of a transverse crack.}, number={6}, journal={SMART MATERIALS AND STRUCTURES}, author={Prabhugoud, M and Peters, K}, year={2003}, month={Dec}, pages={914–924} }