@article{yang_harrysson_west_cormier_park_peters_2015, title={Low-energy drop weight performance of cellular sandwich panels}, volume={21}, ISSN={["1758-7670"]}, DOI={10.1108/rpj-08-2013-0083}, abstractNote={
               Purpose
                – The aim of this study is to perform a comparative study on sandwich structures with several types of three-dimensional (3D) reticulate cellular structural core designs for their low-energy impact absorption abilities using powder bed additive manufacturing methods. 3D reticulate cellular structures possess promising potentials in various applications with sandwich structure designs. One of the properties critical to the sandwich structures in applications, such as aerospace and automobile components, is the low-energy impact performance. 
            }, number={4}, journal={RAPID PROTOTYPING JOURNAL}, author={Yang, Li and Harrysson, Ola A. and West, Harvey A., II and Cormier, Denis R. and Park, Chun and Peters, Kara}, year={2015}, pages={433–442} }
 @article{park_peters_2012, title={Comparison of damage measures based on fiber Bragg grating spectra}, volume={23}, ISSN={["1361-6501"]}, DOI={10.1088/0957-0233/23/2/025105}, abstractNote={We compare the performance of four different damage measures based on the full spectral response of fiber Bragg grating (FBG) sensors: spectral bandwidth, number of peaks, cross-correlation coefficient and fractal dimension. These damage measures provide a rapid indication of the extent of damage near the FBG sensor. Each damage measure is applied to data simulating the response of a FBG to a pure strain gradient and experimental data from FBG sensors embedded in a laminate subjected to multiple impacts. The cross-correlation coefficient and number of peaks did not perform well for the experimental data. The spectral bandwidth presented a low sensitivity to noise and a high sensitivity to rapidly increasing strain fields, whereas the fractal dimension was more sensitive to more gradually changing strain fields. Ultimately, the best strategy would be to fuse the results of the spectral bandwidth and fractal dimension damage measures to incorporate the strengths of each approach. At the same time, this study highlighted the challenges in using such spectral data from FBG sensors embedded in structural materials, primarily due to the variability in response between sensors exposed to the same damage states.}, number={2}, journal={MEASUREMENT SCIENCE AND TECHNOLOGY}, author={Park, Chun and Peters, Kara}, year={2012}, month={Feb} }
 @article{park_peters_2012, title={Optimization of Embedded Sensor Placement for Structural Health Monitoring of Composite Airframes}, volume={50}, ISSN={["0001-1452"]}, DOI={10.2514/1.j051729}, abstractNote={Thisstudy develops anoptimization methodspecifically for embeddedsensors forstructural health monitoring of a composite laminated aircraft structure. The chosen cost function is the component lifetime, balancing both the positive benefits of the condition-based monitoring enabled by the sensor information with the negative costs of the structural-performance degradation.Theoptical-fiberspacingisoptimized,ratherthantheplacement ofindividual sensors. Sensor interaction with damage and sensor-feature extraction are included into the optimization problem through experimentally derived probabilistic models. The resulting sensor-placement optimization has regions of decreasing laminate lifetime and regions of increasing laminate lifetime as a function of sensor spacing. A critical sensor spacing is also calculated, below which sensors are not recommended to be embedded.}, number={11}, journal={AIAA JOURNAL}, author={Park, Chun and Peters, Kara}, year={2012}, month={Nov}, pages={2536–2545} }
 @article{vella_chadderdon_selfridge_schultz_webb_park_peters_zikry_2010, title={Full-spectrum interrogation of fiber Bragg gratings at 100 kHz for detection of impact loading}, volume={21}, ISSN={["1361-6501"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-77958167493&partnerID=MN8TOARS}, DOI={10.1088/0957-0233/21/9/094009}, abstractNote={This paper explains key innovations that allow monitoring of detailed spectral features of an FBG in response to impact loading. The new system demonstrates capture of FBG spectral data at rates of 100 kHz. Rapid capture of the entire reflection spectrum at such high reading rates shows important features that are missed when using systems that merely track changes in the peak location of the spectrum. The update rate of 100 kHz allows resolution of features that occur on transient time scales as short as 10 µs. This paper gives a detailed description of the unique features of the apparatus and processes used to capture the data at such a rapid rate. Furthermore, we demonstrate this interrogation scheme on a composite laminate system during impact.}, number={9}, journal={MEASUREMENT SCIENCE AND TECHNOLOGY}, author={Vella, T. and Chadderdon, S. and Selfridge, R. and Schultz, S. and Webb, S. and Park, C. and Peters, K. and Zikry, M.}, year={2010}, month={Sep} }
 @article{park_peters_zikry_haber_schultz_selfridge_2010, title={Peak wavelength interrogation of fiber Bragg grating sensors during impact events}, volume={19}, ISSN={["1361-665X"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-77949894501&partnerID=MN8TOARS}, DOI={10.1088/0964-1726/19/4/045015}, abstractNote={In this paper, we embed fiber Bragg grating (FBG) sensors in graphite fiber–epoxy woven composite laminates to detect evolving damage modes. The peak wavelengths of the FBG sensors are interrogated at 625 and 295 kHz, while the laminates are subjected to 11.0 J low-velocity impact events. It is demonstrated that 295 kHz interrogation is sufficient for accurately collecting the dynamic response of the sensors. The FBG sensors embedded at the laminate midplanes successfully reconstructed the global laminate response to impact. The maximum and full width at half-maximum (FWHM) for the relative strain histories demonstrated the same trends as the maximum and FWHM of the contact force histories measured from the impactor. More noise was present in the strain histories obtained from the FBG sensors than the contact force histories, as the embedded FBGs were sensitive to local perturbations in the stress state. The FBG sensors embedded below the midplane of the laminate were closer to the damage regions and measured complex strain histories. In one case, this strain history revealed the presence of delamination.}, number={4}, journal={SMART MATERIALS AND STRUCTURES}, author={Park, Chun and Peters, Kara and Zikry, Mohammed and Haber, Todd and Schultz, Stephen and Selfridge, Richard}, year={2010}, month={Apr} }
 @article{park_peters_zikry_2010, title={The Effects of Embedded Optical Fiber Density on the Impact Response and Lifetime of Laminated Composites}, volume={21}, ISSN={["1530-8138"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-78650907528&partnerID=MN8TOARS}, DOI={10.1177/1045389x10390250}, abstractNote={ Graphite fiber/epoxy, two-dimensional woven composite laminates were fabricated with various densities of embedded optical fibers at the midplane. The specimens were subjected to multiple low-velocity impacts until failure, as the energy dissipated by the laminate and the maximum contact force were measured for each impact event. Cumulative probability distributions were calculated for each embedded optical fiber density, from which probability distribution functions in terms of embedded optical fiber density were extrapolated. At low fiber densities, the total energy dissipated by the specimen and the total maximum contact force over the lifetime of the specimen decreased rapidly with increasing optical fiber density. After a threshold embedded optical fiber density, the optical fibers dominated the failure mode of the laminate and the laminate lifetime, and the overall stiffness was not affected by the embedded optical fiber density. The obtained probability distribution functions could be applied for future optimization of embedded sensor placement for smart composite structures. }, number={18}, journal={JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES}, author={Park, Chun and Peters, Kara and Zikry, Mohammed}, year={2010}, month={Dec}, pages={1819–1829} }
 @article{park_peters_zikry_2010, title={The Role of Embedded Sensors in Damage Assessment of Composite Laminates}, volume={7648}, ISSN={["0277-786X"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-77953489216&partnerID=MN8TOARS}, DOI={10.1117/12.847634}, abstractNote={Various densities of optical fibers are embedded into a total of eighty woven, graphite fiber-epoxy composite laminates, for which the response to low velocity impacts are evaluated. The goal of this work is to determine the role of hostsensor interaction on the lifetime of the host material system. The woven composites are subjected to multiple impacts at 14.5 J until perforation of the specimen. We obtain the energy dissipated by the laminate and the maximum contact force between the impactor laminate for each strike. From these experimental data we calculate the statistical distribution of the total energy dissipated at failure as a function of embedded optical fiber density. The total dissipated energy, a measure of the specimen lifetime, decreased with increasing embedded optical fiber density, however remained constant after a threshold density was reached. The total maximum contact force per specimen, a measure of the specimen stiffness, continued to decrease with the number of embedded optical fibers.}, journal={SMART SENSOR PHENOMENA, TECHNOLOGY, NETWORKS, AND SYSTEMS 2010}, author={Park, Chun and Peters, Kara and Zikry, Mohammed}, year={2010} }
 @inproceedings{propst_garrett_park_peters_zikry_2009, title={Sensor networks for in-situ failure identification in woven composites}, volume={7293}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-66749128673&partnerID=MN8TOARS}, DOI={10.1117/12.815743}, abstractNote={This paper presents experimental measurements of the response of woven composite laminates to multiple low-velocity impacts. Damage initiation and progression occur at multiple physical and temporal scales in heterogeneous materials, including fiber breakage, matrix cracking, delamination and matrix relaxation. The sensor/interrogators were therefore chosen specifically to provide insight into the order and progression of different failure modes. Measurements of the contact force between the impactor and composite are measured throughout impact. Additionally, the dissipated energy per impact event is also calculated from the impactor velocity. Surface mounted and embedded fiber Bragg grating sensors are used for the measurement of the laminate response. Peak wavelength measurements are performed during impact at 1 kHz, while full-spectral scanning is performed at 5 Hz during relaxation period of the laminate immediately after impact and quasi-statically to measure post-impact residual strain states within the laminate. The results highlight the depth of information embedded within the FBG full-spectral data sensors, as well as the added insight to be gained from combined global-local measurements.}, booktitle={SMASIS 2009, vol 2}, author={Propst, A. and Garrett, R. and Park, C. and Peters, K. and Zikry, M.}, year={2009}, pages={477–485} }