Now showing items 1-20 of 143

    • 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 ...
    • 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 ...
    • Reduced order modeling for the dynamics of jointed structures through hyper-reduced interface representation 

      Balaji, Nidish Narayanaa; Dreher, Tobias; Krack, Malte; Brake, Matthew R.W. (2021)
      One strategy to develop both accurate and computationally tractable models of jointed structures is reduced order modeling through hyper-reduced representations of the interfaces in contact. Hyper reduction refers to reduction techniques that result in a Reduced Order Model (ROM) that is complete by itself, i.e., all displacements and forces are fully ...
    • How Well Do Commonly Used Co-contraction Indices Approximate Lower Limb Joint Stiffness Trends During Gait for Individuals Post-stroke? 

      Li, Geng; Shourijeh, Mohammad S.; Ao, Di; Patten, Carolynn; Fregly, Benjamin J.; (2021)
      Muscle co-contraction generates joint stiffness to improve stability and accuracy during limb movement but at the expense of higher energetic cost. However, quantification of joint stiffness is difficult using either experimental or computational means. In contrast, quantification of muscle co-contraction using an EMG-based Co-Contraction Index (CCI) ...
    • Lateral flow immunochromatographic assay on a single piece of paper 

      Jiang, Xue; Lillehoj, Peter B. (2021)
      Lateral flow immunochromatographic assays (LFIAs) are analytical devices used to detect the presence of one or more target analytes in a liquid sample. While LFIAs are one of the simplest and inexpensive types of immunoassays, they consist of multiple components (sample pad, conjugate pad, membrane, absorbent pad, backing card) and materials, requiring ...
    • A linear-elasticity-based mesh moving method with no cycle-to-cycle accumulated distortion 

      Tonon, Patrícia; Sanches, Rodolfo André Kuche; Takizawa, Kenji; Tezduyar, Tayfun E. (2021)
      Good mesh moving methods are always part of what makes moving-mesh methods good in computation of flow problems with moving boundaries and interfaces, including fluid–structure interaction. Moving-mesh methods, such as the space–time (ST) and arbitrary Lagrangian–Eulerian (ALE) methods, enable mesh-resolution control near solid surfaces and thus ...
    • In situ, real-time measurements of contact pressure internal to jointed interfaces during dynamic excitation of an assembled structure 

      Dreher, T.; Brake, M.R.W.; Seeger, B.; Krack, M. (2021)
      Despite the ubiquitousness of jointed structures, the nonlinear interfacial behavior within bolted joints is still an insufficiently studied and poorly understood environment. For the development of effective simulation approaches, a deeper understanding of the salient physical effects within the contact surface is needed. This work studies the ...
    • Electrochemical Biosensors for Cytokine Profiling: Recent Advancements and Possibilities in the Near Future 

      Dutta, Nirmita; Lillehoj, Peter B.; Estrela, Pedro; Dutta, Gorachand (2021)
      Cytokines are soluble proteins secreted by immune cells that act as molecular messengers relaying instructions and mediating various functions performed by the cellular counterparts of the immune system, by means of a synchronized cascade of signaling pathways. Aberrant expression of cytokines can be indicative of anomalous behavior of the immunoregulatory ...
    • U-duct turbulent-flow computation with the ST-VMS method and isogeometric discretization 

      Aydinbakar, Levent; Takizawa, Kenji; Tezduyar, Tayfun E.; Matsuda, Daisaku (2021)
      The U-duct turbulent flow is a known benchmark problem with the computational challenges of high Reynolds number, high curvature and strong flow dependence on the inflow profile. We use this benchmark problem to test and evaluate the Space–Time Variational Multiscale (ST-VMS) method with ST isogeometric discretization. A fully-developed flow field ...
    • Space–time VMS isogeometric analysis of the Taylor–Couette flow 

      Aydinbakar, Levent; Takizawa, Kenji; Tezduyar, Tayfun E.; Kuraishi, Takashi (2021)
      The Taylor–Couette flow is a classical fluid mechanics problem that exhibits, depending on the Reynolds number, a range of flow patterns, with the interesting ones having small-scale structures, and sometimes even wavy nature. Accurate representation of these flow patterns in computational flow analysis requires methods that can, with a reasonable ...
    • 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 ...
    • 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 ...
    • 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 ...
    • 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 ...
    • Permeability estimation on tomographic images using curved boundary schemes in the lattice Boltzmann method 

      Rao, Parthib; Schaefer, Laura (2020)
      The lattice Boltzmann method (LBM) is a widely-used numerical technique for simulation of single- and two-phase flow in geometries that are obtained using tomographic imaging of natural porous media. Due to ease of implementation and numerical robustness, a vast majority of LBM-based pore-scale simulations employ the so-called bounceback scheme to ...
    • A predictive model of the temperature-dependent inactivation of coronaviruses 

      Yap, Te Faye; Liu, Zhen; Shveda, Rachel A.; Preston, Daniel J. (2020)
      The COVID-19 pandemic has stressed healthcare systems and supply lines, forcing medical doctors to risk infection by decontaminating and reusing single-use personal protective equipment. The uncertain future of the pandemic is compounded by limited data on the ability of the responsible virus, SARS-CoV-2, to survive across various climates, preventing ...
    • Data-driven predictions of a multiscale Lorenz 96 chaotic system using machine-learning methods: reservoir computing, artificial neural network, and long short-term memory network 

      Chattopadhyay, Ashesh; Hassanzadeh, Pedram; Subramanian, Devika (2020)
      In this paper, the performance of three machine-learning methods for predicting short-term evolution and for reproducing the long-term statistics of a multiscale spatiotemporal Lorenz 96 system is examined. The methods are an echo state network (ESN, which is a type of reservoir computing; hereafter RC–ESN), a deep feed-forward artificial neural ...
    • Influence of musculoskeletal model parameter values on prediction of accurate knee contact forces during walking 

      Serrancolí, Gil; Kinney, Allison L.; Fregly, Benjamin J. (2020)
      Treatment design for musculoskeletal disorders using in silico patient-specific dynamic simulations is becoming a clinical possibility. However, these simulations are sensitive to model parameter values that are difficult to measure experimentally, and the influence of uncertainties in these parameter values on the accuracy of estimated knee contact ...
    • A Review of Damping Models for Structures With Mechanical Joints 

      Mathis, Allen T.; Balaji, Nidish N.; Kuether, Robert J.; Brink, Adam R.; Brake, Matthew R.W.; (2020)
      In a standard design practice, it is often necessary to assemble engineered structures from individually manufactured parts. Ideally, the assembled system should perform as if the connections between the components were perfect, that is, as if the system were a single monolithic piece. However, the fasteners used in those connections, such as mechanical ...