@article{daye_marashi_lee_peters_2024, title={Dynamic Deployment Sensing of Thin-Shell Composite Structures with Fiber Bragg Gratings}, volume={12951}, ISBN={["978-1-5106-7208-6"]}, ISSN={["1996-756X"]}, DOI={10.1117/12.3010518}, abstractNote={The efficacy of using Fiber-Bragg Grating (FBG) sensors for the purpose of sensing and characterizing dynamic deployment of bistable composite tape springs is investigated in this paper. Ultra-thin composite structures such as tape springs have seen increased popularity in spacecraft structures due to enabling the precise deployment of flexible solar arrays, sails, reflectors, and antennas. These composite members can elastically transition from either the coiled or folded state to the deployed extended state while possessing superior stiffness, thermal properties, mass efficiency, and compactness when compared to their metal counterparts. Bistability is leveraged to influence more controllable self-deployment and energy efficient stowage, while reducing or eliminating the need for mechanical restraints or motorized deployment. However, a need exists to monitor both the deployment dynamics and overall structural health of the deployed member. Fiber optic sensors such as FBGs have the capability to sense pressure, temperature, and mechanical strain. Due to their relative thinness, low mass, and flexibility, fiber optics may be integrated into these deployable composite structures without significantly interfering with bistability, packaging, or deployability. This paper experimentally demonstrates dynamic strain sensing of deploying bistable composite tape springs via the integration of fiber optics containing FBG sensors. Free deployment from both coiled and folded stowed configurations are characterized.}, journal={HEALTH MONITORING OF STRUCTURAL AND BIOLOGICAL SYSTEMS XVIII}, author={Daye, Jacob G. and Marashi, Cameron and Lee, Andrew J. and Peters, Kara}, year={2024} }
 @article{marashi_peters_2024, title={Flow-Coating of Adhesively Bonded Optical Fiber Acoustic Couplers}, volume={12951}, ISBN={["978-1-5106-7208-6"]}, ISSN={["1996-756X"]}, DOI={10.1117/12.3010823}, abstractNote={This paper presents a new flow-coating method to fabricate adhesively bonded optical fiber coupler for acoustic signals. The goal is to decrease losses as acoustic signals representing Lamb waves are transferred from one fiber to another. The flow-coating method significantly improves the geometry of the adhesive in the coupler. As a result, the losses to the acoustic signal energy are significantly reduced in the coupler.}, journal={HEALTH MONITORING OF STRUCTURAL AND BIOLOGICAL SYSTEMS XVIII}, author={Marashi, Cameron and Peters, Kara}, year={2024} }
 @article{soman_marashi_filipkowski_buczynski_peters_2024, title={Studying the elastic wave mode propagation in D-shaped optical fibers}, volume={12951}, ISBN={["978-1-5106-7208-6"]}, ISSN={["1996-756X"]}, DOI={10.1117/12.3010425}, abstractNote={To perform active Structural Health Monitoring (SHM) Guided Waves (GW) have received great interest as they can inspect large areas with a few sensors and are sensitive to barely-visible structural damages. Fiber Bragg Grating (FBG) sensors offer several advantages, but their use has been limited for the GW sensing due to its limited sensitivity. FBG sensors in the edge-filtering configuration have overcome this issue with sensitivity and there is a renewed interest in their use. The sensitivity of the FBG sensors can be further improved through the use of the remote bonding. One of the challenges with the effective and repetitive measurements with the FBG sensors is uncertainty in the bond quality. This is especially important due to the small area of contact of the fiber with the structure. A solution to this is the use of a D-shaped optical fiber which will increase the area in contact. This paper experimentally investigates the coupling of the wave from the structure into the D-shaped fiber. 4 different geometries of optical fiber are studied and the coupling and the propagation amplitudes are investigated using 3D laser Doppler vibrometery measurements.}, journal={HEALTH MONITORING OF STRUCTURAL AND BIOLOGICAL SYSTEMS XVIII}, author={Soman, Rohan and Marashi, Cameron and Filipkowski, Adam and Buczynski, Ryszard and Peters, Kara}, year={2024} }
 @article{marashi_bradford_peters_2023, title={Laser Doppler vibrometry measurements of acoustic attenuation in optical fiber waveguides}, volume={62}, ISSN={["2155-3165"]}, DOI={10.1364/AO.483827}, abstractNote={Fiber Bragg grating (FBG) sensors have been widely applied for structural health monitoring applications. In some applications, remote bonding of the optical fiber is applied, where ultrasonic waves are coupled from the structure to the optical fiber and propagated along the fiber to the FBG sensor. The distance that this signal can propagate along the optical fiber without decaying below a threshold value can be critical to the area of the structure that can be monitored per sensor. In this paper, we develop a method to measure the acoustic mode attenuation of fiber waveguides based on laser Doppler vibrometry (LDV) that is independent of the fiber type. In order to validate the method, we compare attenuation measurements on single-mode optical fibers using both the LDV and FBG sensor methods. Once the method is validated, experimental measurements of different coated and uncoated optical fibers are performed to quantify the role of the fiber diameter on the attenuation coefficient. As the radius of the waveguide decreases, the signal attenuation increases exponentially.}, number={16}, journal={APPLIED OPTICS}, author={Marashi, Cameron Sepehr and Bradford, Philip and Peters, Kara}, year={2023}, month={Jun}, pages={E119–E124} }
 @article{kim_marashi_wee_peters_2021, title={Acoustic wave coupling between optical fibers of different geometries}, volume={60}, ISSN={["2155-3165"]}, DOI={10.1364/AO.441494}, abstractNote={In this study, we investigate coupling of acoustic guided waves from
					different types of input fibers, through a bonded coupler, to an
					optical fiber. These acoustic waves can then be detected with
					conventional fiber Bragg gratings (FBGs). The input waves are measured
					using a high-resolution 3D laser Doppler vibrometer, and the output
					waves in the optical fiber are measured using an FBG. We demonstrate
					that the wave coupling between two waveguides varies with the
					cross-sectional area and the modulus of elasticity of the fibers.}, number={36}, journal={APPLIED OPTICS}, author={Kim, Jee Myung and Marashi, Cameron and Wee, Junghyun and Peters, Kara}, year={2021}, month={Dec}, pages={11042–11049} }
 @article{kim_marashi_wee_peters_2021, title={Investigation on acoustic wave transfer variation between fibers of different diameters and types using acoustic coupler}, volume={11591}, ISSN={["1996-756X"]}, DOI={10.1117/12.2584249}, abstractNote={When using fiber Bragg grating (FBG) sensors in structural health monitoring (SHM) applications, one of the drawbacks is that the sensor location is fixed once it is installed and it is difficult to extend an already existing system. The use of an acoustic coupler to transfer fiber guided traveling waves from one fiber to another could resolve this issue as the system could be modified for extension. In this study, we investigate the coupling of optical fiber guided waves between two different types of fibers through an acoustic coupler. Specifically, input waves are launched into an input fiber and coupled to an output fiber through the acoustic coupler. The input waves are measured using a high-resolution 3D laser Doppler Vibrometer (LDV) and the output waves from the output fiber are measured using an FBG. We demonstrate that the wave coupling between two fibers varies with the cross-sectional area of the input fiber.}, journal={SENSORS AND SMART STRUCTURES TECHNOLOGIES FOR CIVIL, MECHANICAL, AND AEROSPACE SYSTEMS 2021}, author={Kim, Jee Myung and Marashi, Cameron and Wee, Junghyun and Peters, Kara}, year={2021} }