@article{velasco_seng_hodges_peters_pankow_schultz_2024, title={Dynamic measurement of ballistic impact using an optical fibre sensor}, volume={33}, ISSN={["1361-665X"]}, DOI={10.1088/1361-665X/ad27fd}, abstractNote={
 An optical fibre-based sensor is developed for measuring the dynamics of the back face deformation of soft body armor. The measurement system consists of embedding an optical fibre into a thin silicone mat to increase survivability. The silicone sensor mat is placed between the soft body armor and the backing material. The optical fibre experiences times of sticking and slipping. The portions of the impact with the optical fibre stuck are reconstructed into slipping-equivalent strain using exponential extrapolation from adjacent slipping portions. The strain on the optical fibre is related to the projectile acceleration when the optical fibre is slipping. The strain is measured with the optical fibre sensor using a fibre Bragg grating. The system is characterized using a gas gun in combination with high-speed imaging. The system is experimentally demonstrated at the Army Test Center in Aberdeen, MD. Of the 23 shots 17 had an error less than 10%.}, number={3}, journal={SMART MATERIALS AND STRUCTURES}, author={Velasco, Ivann and Seng, Frederick and Hodges, Greyson and Peters, Kara and Pankow, Mark and Schultz, Stephen}, year={2024}, month={Mar} }
 @article{mendoza_graham_matejunas_hodges_siviour_pankow_lamberson_2023, title={Evaluation of Low-Cycle Impact Fatigue Damage in CFRPs using the Virtual Fields Method}, ISSN={["2199-7454"]}, DOI={10.1007/s40870-023-00386-7}, journal={JOURNAL OF DYNAMIC BEHAVIOR OF MATERIALS}, author={Mendoza, I. and Graham, A. and Matejunas, A. and Hodges, G. and Siviour, C. and Pankow, M. and Lamberson, L.}, year={2023}, month={Aug} }
 @article{hodges_pankow_2023, title={Modeling Micrometeoroid and Orbital Debris Impact on Composite Truss Tubes}, ISBN={["978-3-031-17477-3", "978-3-031-17474-2"]}, ISSN={["2191-5652"]}, DOI={10.1007/978-3-031-17475-9_5}, abstractNote={The growing congestion of space with large satellite constellations and the growing capabilities of on-orbit servicing assembly and manufacturing (OSAM) pose new problems for designers. The effects of micrometeoroid and orbital debris (MMOD) on these structures need to be well understood to ensure longevity and safety of operation. Composite truss members provide the structural backbone for in-space assembled structures, one example being the in-space assembled telescope (iSAT). Limited research has been conducted on the effects MMOD impacts have on composite trusses and their residual strength, post impact. To study the effects of MMOD impacts on composite trusses and to quantify their reduction in strength, a meso-scale hybrid FEA/SPH model was created. Simulation results of MMOD impacts were compared to experimental tests to validate the model’s damage predicting capabilities. Results from the damage reduction simulations can be used to further study the effects of MMOD impacts on in-space assembled structures.}, journal={THERMOMECHANICS & INFRARED IMAGING, INVERSE PROBLEM METHODOLOGIES AND MECHANICS OF ADDITIVE & ADVANCED MANUFACTURED MATERIALS, VOL 6}, author={Hodges, Greyson and Pankow, Mark}, year={2023}, pages={35–38} }
 @article{hodges_noevere_velasco_hackney_seng_schultz_peters_pankow_2022, title={Ballistic loading and survivability of optical fiber sensing layers for soft body armor evaluation}, volume={73}, ISSN={["1095-9912"]}, DOI={10.1016/j.yofte.2022.103043}, abstractNote={• To survive impact the contact radius between the fiber and impactor must be increased. • Silicone was chosen due to its high strain to failure and elastic properties. • In situ silicone sensors have shown to minimally effect back face deformation depth. • Silicone sensing mats are able to protect optical fibers during impact. The authors previously demonstrated the use of FBG sensors in Kevlar mats behind body armor to measure the transient back face deformation (BFD) during ballistic testing. This paper presents a novel sensor system based on a Fiber Bragg Grating embedded in silicone mats to improve the survivability of the body armor in-situ strain sensing layers. Due to the large amount of deformation, a relative slip between the optical fibers and the supporting structure is needed to maintain the performance of the sensors and determine the relationship between the measured strain and deformation shape. Two silicone materials were tested, Smooth-Sil 950 and Sorta-Clear 40, in both 1 mm and 2 mm thicknesses to evaluate their survivability and impact on BFD. To enhance slipping between the fibers and surrounding silicone a thin layer of petroleum jelly was placed on the fibers prior to being cast in the silicone mats. The 1 mm Sorta-Clear 40 mats performed best in silicone survivability, FBG survivability and minimal impact on the BFD. The new system improves on key deficiencies that were found from inserting the fibers directly into the Kevlar with minimal to no impact on the back face deformation.}, journal={OPTICAL FIBER TECHNOLOGY}, author={Hodges, Greyson and Noevere, Alexander and Velasco, Ivann and Hackney, Drew and Seng, Frederick and Schultz, Stephen and Peters, Kara and Pankow, Mark}, year={2022}, month={Oct} }
 @article{islam_perera_black_phillips_chen_hodges_jackman_liu_kim_zikry_et al._2022, title={Template‐Free Scalable Fabrication of Linearly Periodic Microstructures by Controlling Ribbing Defects Phenomenon in Forward Roll Coating for Multifunctional Applications}, volume={9}, ISSN={2196-7350 2196-7350}, url={http://dx.doi.org/10.1002/admi.202201237}, DOI={10.1002/admi.202201237}, abstractNote={Periodic micro/nanoscale structures from nature have inspired the scientific community to adopt surface design for various applications, including superhydrophobic drag reduction. One primary concern of practical applications of such periodic microstructures remains the scalability of conventional microfabrication technologies. This study demonstrates a simple template‐free scalable manufacturing technique to fabricate periodic microstructures by controlling the ribbing defects in the forward roll coating. Viscoelastic composite coating materials are designed for roll‐coating using carbon nanotubes (CNT) and polydimethylsiloxane (PDMS), which helps achieve a controllable ribbing with a periodicity of 114–700 µm. Depending on the process parameters, the patterned microstructures transition from the linear alignment to a random structure. The periodic microstructure enables hydrophobicity as the water contact angles of the samples ranged from 128° to 158°. When towed in a static water pool, a model boat coated with the microstructure film shows 7%–8% faster speed than the boat with a flat PDMS film. The CNT addition shows both mechanical and electrical properties improvement. In a mechanical scratch test, the cohesive failure of the CNT‐PDMS film occurs in ≈90% higher force than bare PDMS. Moreover, the nonconductive bare PDMS shows sheet resistance of 747.84–22.66 Ω □−1 with 0.5 to 2.5 wt% CNT inclusion.}, number={27}, journal={Advanced Materials Interfaces}, publisher={Wiley}, author={Islam, Md Didarul and Perera, Himendra and Black, Benjamin and Phillips, Matthew and Chen, Muh‐Jang and Hodges, Greyson and Jackman, Allyce and Liu, Yuxuan and Kim, Chang‐Jin and Zikry, Mohammed and et al.}, year={2022}, month={Aug}, pages={2201237} }