Mechanical Engineering Commons^™

Gender Dimorphic Acl Strain In Response To Combined Dynamic 3d Knee Joint Loading: Implications For Acl Injury Risk, Kiyonori Mizuno, Jack T. Andrish, Antonie J. Van Den Bogert, Scott G. Mclean

Mechanical Engineering Faculty Publications

While gender-based differences in knee joint anatomies/laxities are well documented, the potential for them to precipitate gender-dimorphic ACL loading and resultant injury risk has not been considered. To this end, we generated gender-specific models of ACL strain as a function of any six degrees of freedom (6DOF) knee joint load state via a combined cadaveric and analytical approach. Continuously varying joint forces and torques were applied to five male and five female cadaveric specimens and recorded along with synchronous knee flexion and ACL strain data. All data (~10,000 samples) were submitted to specimen-specific regression analyses, affording ACL strain predictions as …

Intermittent Behaviour Of A Cracked Rotor In The Resonance Region, Grzegorz Litak, Jerzy T. Sawicki

Mechanical Engineering Faculty Publications

Vibrations of the Jeffcott rotor are modelled by a three degree of freedom system including coupling between lateral and torsional modes. The crack in a rotating shaft of the rotor is introduced via time dependent stiffness with off-diagonal couplings. Applying the external torque to the system allows to observe the effect of crack “breathing” and gain insight into the system. It is manifested in the complex dynamic behaviour of the rotor in the region of internal resonance, showing a quasi-periodic motion or even non-periodic behaviour. In the present paper report, we show the system response to the external torque excitation …

Mechanics-Based Analysis Of Selected Features Of The Exoskeletal Microstructure Of Popillia Japonica, Liang Cheng, Liyun Wang, Anette M. Karlsson

Mechanical Engineering Faculty Publications

We explore key mechanical responses of the layered microstructure found in selected parts of the exoskeletons (pronotum, leg and elytron) of Popillia japonica (Japanese beetle). Image analyses of exoskeleton cross-sections reveal four distinct layered regions. The load-bearing inner three regions (exocuticle, mesocuticle, and endocuticle) consist of multiple chitin-protein layers, in which chitin fibers align in parallel. The exocuticle and mesocuticle have a helicoidal structure, where the stacking sequence is characterized by a gradual rotation of the fiber orientation. The endocuticle has a pseudo-orthogonal structure, where two orthogonal layers are joined by a thin helicoidal region. The mechanics-based analyses suggest that, …

Cracked Rotor Detection By Recurrence Plots, Grzegorz Litak, Jerzy T. Sawicki, Rafał Kaspereka

Mechanical Engineering Faculty Publications

Recurrence plots (RPs) analysis has been used to distinguish cracked and healthy rotor responses. It has been shown that the recurrence criteria of the dynamical systems defined by the RPs can indicate the damages of the rotating shaft using relatively short time series.

An Elaborate Data Set Characterizing The Mechanical Response Of The Foot, Ahmet Erdemir, Pavana A. Sirimamilla, Jason P. Halloran, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Mechanical properties of the foot are responsible for its normal function and play a role in various clinical problems. Specifically, we are interested in quantification of foot mechanical properties to assist the development of computational models for movement analysis and detailed simulations of tissue deformation. Current available data are specific to a foot region and the loading scenarios are limited to a single direction. A data set that incorporates regional response, to quantify individual function of foot components, as well as the overall response, to illustrate their combined operation, does not exist. Furthermore, the combined three-dimensional loading scenarios while measuring …

On Tgo Creep And The Initiation Of A Class Of Fatigue Cracks In Thermal Barrier Coatings, Mercedes T. Hernandez, Anette M. Karlsson, Marion Bartsch

Mechanical Engineering Faculty Publications

The initiation of a class of fatigue cracks observed in thermal barrier coatings (TBCs) subjected to thermal gradient mechanical fatigue testing is investigated. The coating system is based on a NiCoCrAlY bond coat and a partially yttria stabilized zirconia top coat. To explain the development of the cracks of interest, the thermo-mechanical response of the bond coat and the thermally grown oxide (TGO) is examined and quantified through finite element analyses. The models include non-linear and time-dependent behavior such as creep, TGO growth stress, and thermo-mechanical cyclic loading. The simulations suggest that stress-redistribution due to creep can lead to tensile …

Comment On "A Stochastic Biomechanical Model For Risk And Risk Factors Of Non-Contact Anterior Cruciate Ligament Injuries", Antonie J. Van Den Bogert, Scott G. Mclean

Mechanical Engineering Faculty Publications

No abstract provided.

Assessing Vaginal Surgical Skills Using Video Motion Analysis, Gouri B. Diwadkar, Antonie J. Van Den Bogert, Matthew D. Barber, J. Eric Jelovsek

Mechanical Engineering Faculty Publications

OBJECTIVE: To demonstrate the feasibility of using video motion analysis to quantitate a key step of vaginal hysterectomy and define measurable differences between novice and experienced surgical trainees during vaginal hysterectomy.

METHODS: Analyses focused on clamping, transecting, and suturing the left uterosacral ligament. Using a cutoff of 25, trainees were grouped as experienced (n=14) and novice (n=9) based on the total number of vaginal hysterectomies performed by each trainee. Contrasting-groups analysis was used to determine cutoff values that separated novices from experts.

RESULTS: Novice trainees took longer (112 seconds compared with 84 seconds) and had greater cumulative translational motion (92 …

Crack Identification By Multifractal Analysis Of A Dynamic Rotor Response, Grzegorz Litak, Jerzy T. Sawicki

Mechanical Engineering Faculty Publications

Multifractal analysis has been used to diagnose cracked and healthy rotors. Is has been shown that the complexity and regularity criteria of the dynamical systems defined by the multiple scaling of the time series can indicate the damages of the rotating shaft. Relation to the standard power spectrum technique has been also discussed.

Assessing Plastically Dissipated Energy As A Condition For Fatigue Crack Growth, D. Cojocaru, Anette M. Karlsson

Mechanical Engineering Faculty Publications

The suitability of using a proposed condition for simulating cyclic crack propagation in a numerical scheme is qualitatively investigated, employing the finite element method. The propagation criterion is based on a condition that relates the plastically dissipated energy to a critical value. In the finite element simulation scheme, the crack is allowed to propagate when the criterion is satisfied, and the crack propagates until the condition is no longer fulfilled. Experimentally, it is well established that a negative load ratio increases the crack propagation rate, whereas a tensile overload tends to decrease the crack propagation rate. By simulating these load …

A Microfabricated Segmented-Involute-Foil Regenerator For Enhancing Reliability And Performance Of Stirling Engines: Phase Iii Final Report For The Radioisotope Power Conversion Technology Nra Contract Nas3-03124, Mounir B. Ibrahim, David Gedeon, Gary Wood, Jeffrey Mclean

Mechanical Engineering Faculty Publications

Under Phase III of NASA Research Announcement contract NAS3-03124, a prototype nickel segmented-involute-foil regenerator was microfabricated and tested in a Sunpower Frequency-Test-Bed (FTB) Stirling convertor. The team for this effort consisted of Cleveland State University, Gedeon Associates, Sunpower Inc. and International Mezzo Technologies. Testing in the FTB convertor produced about the same efficiency as testing with the original random-fiber regenerator. But the high thermal conductivity of the prototype nickel regenerator was responsible for a significant performance degradation. An efficiency improvement (by a 1.04 factor, according to computer predictions) could have been achieved if the regenerator was made from a low-conductivity …

Mechanics-Based Model For Non-Affine Swelling In Perfluorosulfonic Acid (Pfsa) Membranes, Ahmet Kusoglu, Michael H. Santare, Anette M. Karlsson

Mechanical Engineering Faculty Publications

A mechanics-based model is developed to predict the swelling pressure in perfluorosulfonic acid (PFSA) ionomer membranes during water uptake. The PFSA membrane is represented as a two-phase system, where the water-filled hydrophilic domains are dispersed throughout the hydrophobic polymer matrix. Two representative volume elements (RVEs) are used to represent the nanostructure: (i) a spherical RVE with a spherical hydrophilic domain at the center, and (ii) a cylindrical RVE with a cylindrical hydrophilic domain. The model starts with the non-affine swelling behavior of the membrane and interprets this as a structural reorganization of the RVEs to characterize the microscopic deformation. Swelling …

A Real-Time, 3-D Musculoskeletal Model For Dynamic Simulation Of Arm Movements, Edward K. Chadwick, Dimitra Blana, Antonie J. Van Den Bogert, Robert F. Kirsch

Mechanical Engineering Faculty Publications

Neuroprostheses can be used to restore movement of the upper limb in individuals with high-level spinal cord injury. Development and evaluation of command and control schemes for such devices typically require real-time, ldquopatient-in-the-looprdquo experimentation. A real-time, 3-D, musculoskeletal model of the upper limb has been developed for use in a simulation environment to allow such testing to be carried out noninvasively. The model provides real-time feedback of human arm dynamics that can be displayed to the user in a virtual reality environment. The model has a 3-DOF glenohumeral joint as well as elbow flexion/extension and pronation/supination and contains 22 muscles …

Stress-Strain Behavior Of Perfluorosulfonic Acid Membranes At Various Temperatures And Humidities: Experiments And Phenomenological Modeling, Ahmet Kusoglu, Yaliang Tang, Michael Santare, Anette M. Karlsson, Simon Cleghorn, William B. Johnson

Mechanical Engineering Faculty Publications

The constitutive response of perfluorinated sulfonic acid (PFSA) membranes based on tensile testing is investigated, and a phenomenological constitutive model for the elastoplastic flow behavior as a function of temperature and humidity is proposed. To this end, the G'Sell–Jonas (1979, “Determination of the Plastic Behavior of Solid Polymers at Constant True Strain Rate,” J. Mater. Sci., 14, pp. 583–591) constitutive model for semicrystalline polymers is extended by incorporating, in addition to temperature, relationships between the material constants of this model and the measured relative humidity. By matching the proposed constitutive model to the experimental stress-strain data, useful material constants …

On Stresses Induced In A Thermal Barrier Coating Due To Indentation Testing, Jin Yan, Anette M. Karlsson, Marion Bartsch, Xi Chen

Mechanical Engineering Faculty Publications

Instrumented indentation has been suggested as a method to determine interfacial fracture toughness of thermal barrier coatings. However, in a previous experimental study we showed that the results are ambiguous. In this work, we investigate the experimental results by numerical simulations incorporating the material microstructure. In the numerical simulations, based on finite element analyses, the stress fields that are associated with the loading and unloading of the indenter are investigated. By comparing these stress fields to the damage observed in the experimental study, including crack path and interfacial delaminations, we explain key findings from the experimental observations. Our results suggest …

Extended Kalman Filter Implementation For The Khepera Ii Mobile Robot, Thomas J. Otahal, Herbert G. Tanner

Mechanical Engineering Faculty Publications

The accurate estimation of robot position and orientation in real-time is one of the fundamental challenges in mobile robotics. The Extended Kalman Filter is a nonlinear real-time recursive time domain filter that combines available sensor data to produce an accurate estimate of state, and has been successfully applied to the localization problem in mobile robotics and aircraft navigation. This report describes an Extended Kalman Filter implementa- tion for the Khepera II mobile robotics platform that seeks to produce accurate localization estimates in real-time using wheel odometry data, IR sensor range data, and compass heading data.

Diamond And Related Nanomaterials For Mems/Nems Applications, Rakesh K. Joshi, Ashok Kumar

Mechanical Engineering Faculty Publications

No abstract provided.

Application Of The Actor-Critic Architecture To Functional Electrical Stimulation Control Of A Human Arm, Philip Thomas, Michael Branicky, Antonie Van Den Bogert, Kathleen Jagodnik

Mechanical Engineering Faculty Publications

Clinical tests have shown that the dynamics of a human arm, controlled using Functional Electrical Stimulation (FES), can vary significantly between and during trials. In this paper, we study the application of the actor-critic architecture, with neural networks for the both the actor and the critic, as a controller that can adapt to these changing dynamics of a human arm. Development and tests were done in simulation using a planar arm model and Hill-based muscle dynamics. We begin by training it using a Proportional Derivative (PD) controller as a supervisor. We then make clinically relevant changes to the dynamics of …

Concurrent Simulation Of Neuromuscular Control And Tissue Deformation Is Possible By Adaptive Surrogate Modeling, Jason P. Halloran, Ahmet Erdemir, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

No abstract provided.

Adaptive Surrogate Modeling For Efficient Coupling Of Musculoskeletal Control And Tissue Deformation Models, Jason P. Halloran, Ahmet Erdemir, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Background

Finite element (FE) modeling and multibody dynamics have traditionally been applied separately to the domains of tissue mechanics and musculoskeletal movements, respectively. Simultaneous simulation of both domains is needed when interactions between tissue and movement are of interest, but this has remained largely impractical due to high computational cost.

Method of Approach

Here we present a method for concurrent simulation of tissue and movement, in which state of the art methods are used in each domain, and communication occurs via a surrogate modeling system based on locally weighted regression. The surrogate model only performs FE simulations when regression from …

Multiresolution Wavelet Analysis Of The Dynamics Of A Cracked Rotor, Jerzy T. Sawicki, Asok K. Sen, Grzegorz Litak

Mechanical Engineering Faculty Publications

We examine the dynamics of a healthy rotor and a rotor with a transverse crack, which opens and closes due to its self weight. Using discrete wavelet transform, we perform a multiresolution analysis of the measured vibration signal from each of these rotors. In particular, the measured vibration signal is decomposed into eight frequency bands, and the rms amplitude values of the healthy and cracked rotors are compared in the three lowest-frequency bands. The results indicate that the rms vibration amplitudes for the cracked rotor are larger than those of the healthy rotor in each of these three frequency bands. …