Now showing items 1-20 of 152

    • A wearable textile-based pneumatic energy harvesting system for assistive robotics 

      Shveda, Rachel A.; Rajappan, Anoop; Yap, Te Faye; Liu, Zhen; Bell, Marquise D.; (2022)
      Wearable assistive, rehabilitative, and augmentative devices currently require bulky power supplies, often making these tools more of a burden than an asset. This work introduces a soft, low-profile, textile-based pneumatic energy harvesting system that extracts power directly from the foot strike of a user during walking. Energy is harvested with a ...
    • Next-generation 2D optical strain mapping with strain-sensing smart skin compared to digital image correlation 

      Meng, Wei; Pal, Ashish; Bachilo, Sergei M.; Weisman, R. Bruce; Nagarajaiah, Satish (2022)
      This study reports next generation optical strain measurement with “strain-sensing smart skin” (S4) and a comparison of its performance against the established digital image correlation (DIC) method. S4 measures strain-induced shifts in the emission wavelengths of single-wall carbon nanotubes embedded in a thin film on the specimen. The new S4 film ...
    • Ultrahigh strength, modulus, and conductivity of graphitic fibers by macromolecular coalescence 

      Lee, Dongju; Kim, Seo Gyun; Hong, Seungki; Madrona, Cristina; Oh, Yuna; (2022)
      Theoretical considerations suggest that the strength of carbon nanotube (CNT) fibers be exceptional; however, their mechanical performance values are much lower than the theoretical values. To achieve macroscopic fibers with ultrahigh performance, we developed a method to form multidimensional nanostructures by coalescence of individual nanotubes. ...
    • A hyperelastic extended Kirchhoff–Love shell model with out-of-plane normal stress: I. Out-of-plane deformation 

      Taniguchi, Yasutoshi; Takizawa, Kenji; Otoguro, Yuto; Tezduyar, Tayfun E. (2022)
      This is the first part of a two-part article on a hyperelastic extended Kirchhoff–Love shell model with out-of-plane normal stress. We present the derivation of the new model, with focus on the mechanics of the out-of-plane deformation. Accounting for the out-of-plane normal stress distribution in the out-of-plane direction affects the accuracy in ...
    • Towards physics-inspired data-driven weather forecasting: integrating data assimilation with a deep spatial-transformer-based U-NET in a case study with ERA5 

      Chattopadhyay, Ashesh; Mustafa, Mustafa; Hassanzadeh, Pedram; Bach, Eviatar; Kashinath, Karthik (2022)
      There is growing interest in data-driven weather prediction (DDWP), e.g., using convolutional neural networks such as U-NET that are trained on data from models or reanalysis. Here, we propose three components, inspired by physics, to integrate with commonly used DDWP models in order to improve their forecast accuracy. These components are (1) a deep ...
    • Electromyographic Classification to Control the SPAR Glove 

      Britt, John E.; O'Malley, Marcia K.; Rose, Chad G. (2021)
      The SeptaPose Assistive and Rehabilitative (SPAR) Glove has been developed to assist individuals with upper extremity impairment arising from neuromuscular injury. The glove detects user intent via the MYO wearable electromyography (EMG) device. In this manuscript, pattern recognition tools infer the desired hand pose from EMG activity. The ability ...
    • Evaluation of Optimal Control Approaches for Predicting Active Knee-Ankle-Foot-Orthosis Motion for Individuals With Spinal Cord Injury 

      Febrer-Nafría, Míriam; Fregly, Benjamin J.; Font-Llagunes, Josep M. (2022)
      Gait restoration of individuals with spinal cord injury can be partially achieved using active orthoses or exoskeletons. To improve the walking ability of each patient as much as possible, it is important to personalize the parameters that define the device actuation. This study investigates whether using an optimal control-based predictive simulation ...
    • A consistency analysis of phase-locked-loop testing and control-based continuation for a geometrically nonlinear frictional system 

      Abeloos, G.; Müller, F.; Ferhatoglu, E.; Scheel, M.; Collette, C.; (2022)
      Two of the most popular vibration testing methods for nonlinear structures are control-based continuation and phase-locked-loop testing. In this paper, they are directly compared on the same benchmark system, for the first time, to demonstrate their general capabilities and to discuss practical implementation aspects. The considered system, which is ...
    • Space–time Isogeometric flow analysis with built-in Reynolds-equation limit 

      Kuraishi, Takashi; Takizawa, Kenji; Tezduyar, Tayfun E. (2019)
      We present a space–time (ST) computational flow analysis method with built-in Reynolds-equation limit. The method enables solution of lubrication fluid dynamics problems with a computational cost comparable to that of the Reynolds-equation model for the comparable solution quality, but with the computational flexibility to go beyond the limitations ...
    • Motion and Sash Height (MASH) alarms for efficient fume hood use 

      Kongoletos, Johnathan; Munden, Ethan; Ballew, Jennifer; Preston, Daniel J. (2021)
      Ventilation, including fume hoods, consumes 40–70% of the total energy used by modern laboratories. Energy-conscious fume hood usage—for example, closing the sash when a hood is unused—can significantly reduce energy expenditures due to ventilation. Prior approaches to promote such behaviors among lab users have primarily relied on passive feedback ...
    • A node-numbering-invariant directional length scale for simplex elements 

      Takizawa, Kenji; Ueda, Yuki; Tezduyar, Tayfun E. (2019)
      Variational multiscale methods, and their precursors, stabilized methods, have been very popular in flow computations in the past several decades. Stabilization parameters embedded in most of these methods play a significant role. The parameters almost always involve element length scales, most of the time in specific directions, such as the direction ...
    • A hierarchical classification of adolescent idiopathic scoliosis: Identifying the distinguishing features in 3D spinal deformities 

      Pasha, Saba; Hassanzadeh, Pedram; Ecker, Malcolm; Ho, Victor (2019)
      This study aimed to identify the differentiating parameters of the spinal curves’ 2D projections through a hierarchical classification of the 3D spinal curve in adolescent idiopathic scoliosis (AIS). A total number of 103 right thoracic left lumbar pre-operative AIS patients were included retrospectively and consecutively. A total number of 20 ...
    • Measurement and identification of the nonlinear dynamics of a jointed structure using full-field data; Part II - Nonlinear system identification 

      Jin, Mengshi; Kosova, Giancarlo; Cenedese, Mattia; Chen, Wei; Singh, Aryan; (2022)
      The dynamic responses of assembled structures are greatly affected by the mechanical joints, which are often the cause of nonlinear behavior. To better understand and, in the future, tailor the nonlinearities, accurate methods are needed to characterize the dynamic properties of jointed structures. In this paper, the nonlinear characteristics of a ...
    • Measurement and identification of the nonlinear dynamics of a jointed structure using full-field data, Part I: Measurement of nonlinear dynamics 

      Chen, Wei; Jana, Debasish; Singh, Aryan; Jin, Mengshi; Cenedese, Mattia; (2022)
      Jointed structures are ubiquitous constituents of engineering systems; however, their dynamic properties (e.g., natural frequencies and damping ratios) are challenging to identify correctly due to the complex, nonlinear nature of interfaces. This research seeks to extend the efficacy of traditional experimental methods for linear system identification ...
    • Heterogeneous material mapping methods for patient-specific finite element models of pelvic trabecular bone: A convergence study 

      Babazadeh Naseri, Ata; Dunbar, Nicholas J.; Baines, Andrew J.; Akin, John E.; Higgs III, C. Fred; (2021)
      Patient-specific finite element (FE) models of bone require the assignment of heterogeneous material properties extracted from the subject's computed tomography (CT) images. Though node-based (NB) and element-based (EB) material mapping methods (MMMs) have been proposed, the sensitivity and convergence of FE models to MMM for varying mesh sizes are ...
    • Myoelectric control and neuromusculoskeletal modeling: Complementary technologies for rehabilitation robotics 

      Berning, Jeffrey; Francisco, Gerard E.; Chang, Shuo-Hsiu; Fregly, Benjamin J.; O'Malley, Marcia K. (2021)
      Stroke and spinal cord injury (SCI) are a leading cause of disability in the United States, and researchers have pursued using robotic devices to aid rehabilitation efforts for resulting upper-extremity impairments. To date, however, robotic rehabilitation of the upper limb has produced only limited improvement in functional outcomes compared to ...
    • A quantitative assessment of the model form error of friction models across different interface representations for jointed structures 

      Porter, Justin H.; Balaji, Nidish Narayanaa; Little, Clayton R.; Brake, Matthew R.W. (2022)
      Hysteretic models are widely used to model frictional interactions in joints to recreate experimental behavior. However, it is unclear which models are best suited for fitting or predicting the responses of structures. The present study evaluates 26 friction model/interface representation combinations to quantify the model form error. A Quasi-Static ...
    • Lifetime Prediction Using a Tribology-Aware, Deep Learning-Based Digital Twin of Ball Bearing-Like Tribosystems in Oil and Gas 

      Desai, Prathamesh S.; Granja, Victoria; Higgs, C. Fred (2021)
      The recent decline in crude oil prices due to global competition and COVID-19-related demand issues has highlighted the need for the efficient operation of an oil and gas plant. One such avenue is accurate predictions about the remaining useful life (RUL) of components used in oil and gas plants. A tribosystem is comprised of the surfaces in relative ...
    • Strain Hardening From Elastic-Perfectly Plastic to Perfectly Elastic Indentation Single Asperity Contact 

      Ghaednia, Hamid; Mifflin, Gregory; Lunia, Priyansh; O'Neill, Eoghan O.; Brake, Matthew R. W. (2020)
      Indentation measurements are a crucial technique for measuring mechanical properties. Although several contact models have been developed to relate force-displacement measurements with the mechanical properties, they all consider simplifying assumptions, such as no strain hardening, which significantly affects the predictions. In this study, the ...
    • The Influence of Additively Manufactured Nonlinearities on the Dynamic Response of Assembled Structures 

      Shu, Hang; Smith, Scott A.; Brake, Matthew R.W.; Tribomechadynamics Laboratory (2020)
      Structural dynamic techniques have been proven accurate at predicting the vibrations of single parts (i.e., monolithic specimens), which are widely used in industrial applications. However, vibration analysis of such assemblies often exhibits high variability or nonrepeatability due to jointed interfaces. Inspired by advances in additive manufacturing ...