@article{zhang_ni_gao_shen_sun_guo_wu_jiang_2021, title={Pneumatically Controlled Reconfigurable Bistable Bionic Flower for Robotic Gripper}, ISSN={["2169-5180"]}, DOI={10.1089/soro.2020.0200}, abstractNote={Beyond their colorful appearances and versatile geometries, flowers can self-shape-morph by adapting to environmental changes. Nature-inspired artificial systems that mimic their natural counterparts in function, flexibility, and adaptation find an emerging application in mobile robotics. In this study, a novel reconfigurable bionic flower made of petal-shaped bistable carbon fiber-reinforced composites and actuated by soft pneumatic actuators is presented. A robotic gripper based on the bionic flower was then developed for transportation tasks. First, a bionic petal based on a hybridization of bistable composites was designed and a theoretical model was established to analyze its bistable characteristic. Second, experiments and simulations were performed to analyze the out-of-plane deformation and morphing processes of the bionic petal. Curvature analysis of the closing state and blooming state shows a good match with the theoretical results. Finally, a flower-inspired robotic gripper made of the bionic petal is demonstrated to evaluate its gripping performances, including gripping force, response time, and reliability. The functional tests confirmed that the proposed soft gripper can grip objects of various shapes, sizes, and weights within milliseconds response time. The stable gripping configuration was maintained through the bistability of the bionic petal without continuous pressure consumption. The high reliability of the gripper is very useful for gripping tasks under unstructured environments, where precise control over the robot is not possible.}, journal={SOFT ROBOTICS}, author={Zhang, Zheng and Ni, Xiangqi and Gao, Weiliang and Shen, Hongcheng and Sun, Min and Guo, Guodong and Wu, Huaping and Jiang, Shaofei}, year={2021}, month={Jul} }
 @article{zhou_zhao_li_li_guo_guo_2019, title={A grinding method of face gear mating with a conical spur involute pinion}, volume={141}, ISSN={["0094-114X"]}, DOI={10.1016/j.mechmachtheory.2019.07.013}, abstractNote={A grinding method of face gear manufactured by a disk wheel is proposed in this paper. The computerized generation of the face gear by application of a conical spur involute shaper is presented. The tooth surfaces of the face gear are ground point by point with the disk wheel. In addition, a numerical model for determination of envelope residuals of the ground face gear surfaces is established. This model is used to determine the grinding tracks of the disk wheel according to the prescribed processing precision. The manufacture of four different cases of face gears is simulated by applying a simulation platform to illustrate the effectiveness of the proposed grinding method. The results show that deviations of excess greater than the prescribed processing precision only exist on the fillet surfaces and the root of the ground tooth, and increase from the fillet surfaces to the mean section of the root of the face gear. However, this has no influence on the meshing of the face gear drive. The processing efficiency of the face gear grinding is sufficiently affected by the prescribed processing precision.}, journal={MECHANISM AND MACHINE THEORY}, author={Zhou, Ruchuan and Zhao, Ning and Li, Wang and Li, Rui and Guo, Guodong and Guo, Hui}, year={2019}, month={Nov}, pages={226–244} }
 @article{guo_pankow_peters_2019, title={High-Speed Interrogation Approach for FBG Sensors Using a VCSEL Array Swept Source}, volume={19}, ISSN={["1558-1748"]}, DOI={10.1109/JSEN.2019.2927901}, abstractNote={This paper presents a fiber Bragg grating (FBG) interrogator based on vertical surface cavity emitting lasers (VCSEL). A Fabry–Pérot filter technique is developed to directly calibrate the dynamic wavelength behavior of VCSELs at both low and high sweep rates. A broad bandwidth light source is constructed by multiplexing five VCSELs together to increase the number of FBGs that can be tracked. Scanning of the VCSEL-array is accomplished by a high-speed electronic switch circuit. The developed interrogator achieves a sweep bandwidth of 10 nm at a scanning rate of 4 kHz. Low-velocity impact testing of a composite plate with a surface mounted FBG sensor shows that the wavelength detection error was 2.7% when compared with the FBG strain obtained by a high-speed swept laser.}, number={21}, journal={IEEE SENSORS JOURNAL}, author={Guo, Guodong and Pankow, Mark and Peters, Kara}, year={2019}, month={Nov}, pages={9766–9774} }
 @article{guo_hackney_pankow_peters_2019, title={Shape reconstruction of woven fabrics using fiber bragg grating strain sensors}, volume={28}, ISSN={["1361-665X"]}, DOI={10.1088/1361-665X/ab4ba3}, abstractNote={In this paper we develop a methodology that uses in-plane strain measurements to determine out-of-plane deflection for woven fabrics using an optical fiber based sensor network. A multiplexed fiber Bragg grating (FBG) network is used to collect strain at discrete locations in the fabric. To simplify the problem a circularly shaped two-dimensional woven fabric material under a spherical indenter load is studied. A finite element (FE) model of the fabric behavior, derived from benchmark testing, was used to help develop reconstruction algorithms, some of which account for slipping of the fabric at the clamped boundaries. Due to the large deflections, complex material behavior of the fabric and slipping of the fabric at the outer boundaries, a modified empirical approximation approach was found to be the optimal choice for the deflection reconstruction. Experiments are performed to evaluate one of the algorithms on strain data from FBG sensors for two test cases: bonded to and woven into the fabric. Despite the complex strain on the FBGs bonded to the fabric, the empirical approach well predicts the out-of-plane deflection, except in the region under the indentor, where the fabric deformation was different than that modeled in the FE simulations. This result is promising for structural applications were direct observations of the out-of-plane deflections are not possible. To increase the maximum deflection of the fabric that could be measured, weaving of the FBGs into the fabric is also attempted. This method was less successful, due to the large amount of relative slipping between the optical fiber and the fabric, drastically reducing the strain measured by the FBGs.}, number={12}, journal={SMART MATERIALS AND STRUCTURES}, author={Guo, Guodong and Hackney, Drew and Pankow, Mark and Peters, Kara}, year={2019}, month={Dec} }
 @article{guo_2018, title={Finite element analysis of pre-stretch effects on ballistic impact performance of woven fabrics}, volume={200}, ISSN={["1879-1085"]}, DOI={10.1016/j.compstruct.2018.05.067}, abstractNote={Abstract Pre-stretch effects on ballistic impact performance of woven fabrics that made of Kevlar KM2 is investigated with finite element simulation. Individual yarns of the fabrics are modeled with truss elements incorporated with equivalent material properties of real fiber yarns. Before the projectile is issued, a fabric panel that has a rectangular configuration is pre-stretched by directly applying displacement boundary conditions. This two-step loading condition is realized through results transferring capability offered by the commercial software ABAQUS. Simulation results reveal that pre-stretch can significantly influence the fabric’s ballistic response such as ballistic limit, energy absorption and wave propagation. The fabric with higher pre-stretch absorbs more energy, however fails earlier than the fabric with lower pre-stretch. Parametric studies show that with the increase of pre-stretch, the deformation contour evolves from a pyramid shape that is conventionally observed in non-pre-stretched fabrics into a conical shape.}, journal={COMPOSITE STRUCTURES}, author={Guo, Guodong}, year={2018}, month={Sep}, pages={173–186} }
 @article{guo_hackney_pankow_peters_2017, title={A spectral profile multiplexed FBG sensor network with application to strain measurement in a Kevlar woven fabric}, volume={10168}, ISSN={["1996-756X"]}, DOI={10.1117/12.2260114}, abstractNote={A spectral profile division multiplexed fiber Bragg grating (FBG) sensor network is described in this paper. The unique spectral profile of each sensor in the network is identified as a distinct feature to be interrogated. Spectrum overlap is allowed under working conditions. Thus, a specific wavelength window does not need to be allocated to each sensor as in a wavelength division multiplexed (WDM) network. When the sensors are serially connected in the network, the spectrum output is expressed through a truncated series. To track the wavelength shift of each sensor, the identification problem is transformed to a nonlinear optimization problem, which is then solved by a modified dynamic multi-swarm particle swarm optimizer (DMS-PSO). To demonstrate the application of the developed network, a network consisting of four FBGs was integrated into a Kevlar woven fabric, which was under a quasi-static load imposed by an impactor head. Due to the substantial radial strain in the fabric, the spectrums of different FBGs were found to overlap during the loading process. With the developed interrogating method, the overlapped spectrum would be distinguished thus the wavelength shift of each sensor can be monitored.}, journal={SENSORS AND SMART STRUCTURES TECHNOLOGIES FOR CIVIL, MECHANICAL, AND AEROSPACE SYSTEMS 2017}, author={Guo, Guodong and Hackney, Drew and Pankow, Mark and Peters, Kara}, year={2017} }
 @article{guo_hackney_pankow_peters_2017, title={Interrogation of a spectral profile division multiplexed FBG sensor network using a modified particle swarm optimization method}, volume={28}, ISSN={["1361-6501"]}, DOI={10.1088/1361-6501/aa637f}, abstractNote={This paper applies the concept of spectral profile division multiplexing to track each Bragg wavelength shift in a serially multiplexed fiber Bragg grating (FBG) network. Each sensor in the network is uniquely characterized by its own reflected spectrum shape, thus spectral overlapping is allowed in the wavelength domain. In contrast to the previous literature, spectral distortion caused by multiple reflections and spectral shadowing between FBG sensors, that occur in serial topology sensor networks, are considered in the identification algorithm. To detect the Bragg wavelength shift of each FBG, a nonlinear optimization function based on the output spectrum is constructed and a modified dynamic multi-swarm particle swarm optimizer is employed. The multiplexing approach is experimentally demonstrated on data from multiplexed sensor networks with up to four sensors. The wavelength prediction results show that the method can efficiently interrogate the multiplexed network in these overlapped situations. Specifically, the maximum error in a fully overlapped situation in the specific four sensor network demonstrated here was only 110 pm. A more general analysis of the prediction error and guidelines to optimize the sensor network are the subject of future work.}, number={5}, journal={MEASUREMENT SCIENCE AND TECHNOLOGY}, author={Guo, Guodong and Hackney, Drew and Pankow, Mark and Peters, Kara}, year={2017}, month={May} }
 @article{guo_zhu_2015, title={Cohesive-Shear-Lag Modeling of Interfacial Stress Transfer Between a Monolayer Graphene and a Polymer Substrate}, volume={82}, ISSN={["1528-9036"]}, DOI={10.1115/1.4029635}, abstractNote={Interfacial shear stress transfer of a monolayer graphene on top of a polymer substrate subjected to uniaxial tension was investigated by a cohesive zone model integrated with a shear-lag model. Strain distribution in the graphene flake was found to behave in three stages in general, bonded, damaged, and debonded, as a result of the interfacial stress transfer. By fitting the cohesive-shear-lag model to our experimental results, the interface properties were identified including interface stiffness (74 Tpa/m), shear strength (0.50 Mpa), and mode II fracture toughness (0.08 N/m). Parametric studies showed that larger interface stiffness and/or shear strength can lead to better stress transfer efficiency, and high fracture toughness can delay debonding from occurring. 3D finite element simulations were performed to capture the interfacial stress transfer in graphene flakes with realistic geometries. The present study can provide valuable insight and design guidelines for enhancing interfacial shear stress transfer in nanocomposites, stretchable electronics and other applications based on graphene and other 2D nanomaterials.}, number={3}, journal={JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME}, author={Guo, Guodong and Zhu, Yong}, year={2015}, month={Mar} }