Mechanical Engineering Commons^™

Personal Navigation Via High-Resolution Gait-Corrected Inertial Measurement Units, Özkan Bebek, Michael A. Suster, Srihari Rajgopal, Michael J. Fu, Xuemei Huang, M. Cenk Çavu¸So˘Glu,, Darrin J. Young, Mehran Mehregany, Antonie J. Van Den Bogert, Carlos H. Mastrangelo

Mechanical Engineering Faculty Publications

In this paper, a personal micronavigation system that uses high-resolution gait-corrected inertial measurement units is presented. The goal of this paper is to develop a navigation system that uses secondary inertial variables, such as velocity, to enable long-term precise navigation in the absence of Global Positioning System (GPS) and beacon signals. In this scheme, measured zerovelocity duration from the ground reaction sensors is used to reset the accumulated integration errors from accelerometers and gyroscopes in position calculation. With the described system, an average position error of 4 m is achieved at the end of half-hour walks.

Concurrent Muscoskeletal Dynamics And Finite Element Analysis Predicts Altered Gait Patterns To Reduce Foot Tissue Loading, Jason P. Halloran, Marko Ackermann, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Current computational methods for simulating locomotion have primarily used muscle-driven multibody dynamics, in which neuromuscular control is optimized. Such simulations generally represent joints and soft tissue as simple kinematic or elastic elements for computational efficiency. These assumptions limit application in studies such as ligament injury or osteoarthritis, where local tissue loading must be predicted. Conversely, tissue can be simulated using the finite element method with assumed or measured boundary conditions, but this does not represent the effects of whole body dynamics and neuromuscular control. Coupling the two domains would overcome these limitations and allow prediction of movement strategies guided by …

Auxiliary State Variables For Rotor Crack Detection, Zbigniew Kulesza, Jerzy T. Sawicki

Mechanical Engineering Faculty Publications

In the present study, a new model-based method for rotor crack detection and crack location is proposed. The finiteelement model of the rotor-bearing system accounts for the breathing mechanism of the crack. The model of the rotor system is augmented with an auxiliary single-degree-of-freedom oscillator. The observer is designed and the estimates of its two auxiliary state variables are proposed as crack indicators. The crack location along the shaft is determined by designing a set of observers, which calculate the values of these indicators for different possible crack locations along the shaft. The proposed method is validated numerically and the …

Longitudinal Sex Differences During Landing In Knee Abduction In Young Athletes, Kevin R. Ford, Robert Shapiro, Gregory D. Meyer, Antonie J. Van Den Bogert, Timothy E. Hewett

Mechanical Engineering Faculty Publications

Purpose—

The objective of this study was to determine if biomechanical and neuromuscular risk factors related to abnormal movement patterns increased in females, but not males, during the adolescent growth spurt.

Methods—

315 subjects participated in two testing sessions approximately one year apart. Male and female subjects were classified based on their maturation status as pubertal or post-pubertal.Three trials of a drop vertical jump (DVJ) were collected. Maximum knee abduction angle and external moments were calculated during the DVJ deceleration phase using a 3D motion analysis system. Changes in knee abduction from the first to second year were compared among …

High Strength And Light-Weight Materials Inspired By The Exoskeleton Of Arthropods, Anette M. Karlsson

Mechanical Engineering Faculty Publications

This work investigates the multiscaled structure and the constitutive behavior of the exoskeleton of arthropods (Japanese beetle) along with the response of biomimicked structures. Image analysis (SEM and TEM) revealed three load-bearing regions comprised of chitin-protein fiber layers orientated parallel to the cuticle surface. The chitin fibers in the exocuticle and mesocuticle are organized in a helicoidal structure (layers stacked with a small rotational angle relative to their adjacent layers). The endocuticle has a distinct pseudo-orthogonal pattern, characterized by a thin transitional helicoidal region inserted between two orthogonal layers. Idealized mechanics based models showed that the pseudo-orthogonal structure redistributes the …

Optimization And Evaluation Of A Proportional Derivative Controller For Planar Arm Movement, Kathleen M. Jagodnik, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

In most clinical applications of functional electrical stimulation (FES), the timing and amplitude of electrical stimuli have been controlled by open-loop pattern generators. The control of upper extremity reaching movements, however, will require feedback control to achieve the required precision. Here we present three controllers using proportional derivative (PD) feedback to stimulate six arm muscles, using two joint angle sensors. Controllers were first optimized and then evaluated on a computational arm model that includes musculoskeletal dynamics. Feedback gains were optimized by minimizing a weighted sum of position errors and muscle forces. Generalizability of the controllers was evaluated by performing movements …

Optimality Principles For Model-Based Prediction Of Human Gait, Marko Ackermann, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Although humans have a large repertoire of potential movements, gait patterns tend to be stereotypical and appear to be selected according to optimality principles such as minimal energy. When applied to dynamic musculoskeletal models such optimality principles might be used to predict how a patient's gait adapts to mechanical interventions such as prosthetic devices or surgery. In this paper we study the effects of different performance criteria on predicted gait patterns using a 2D musculoskeletal model. The associated optimal control problem for a family of different cost functions was solved utilizing the direct collocation method. It was found that fatigue-like …

On The Effective Elastic Properties Of Macroscopically Isotropic Media Containing Randomly Dispersed Spherical Particles, D. Cojocaru, Anette M. Karlsson

Mechanical Engineering Faculty Publications

computational scheme for estimating the effective elastic properties of a particle reinforced matrix is investigated. The randomly distributed same-sized spherical particles are assumed to result in a composite material that is macroscopically isotropic. The scheme results in a computational efficient method to establish the correct bulk and shear moduli by representing the three-dimensional (3D) structure in a two-dimensional configuration. To this end, the statistically equivalent area fraction is defined in this work, which depends on two parameters: the particle volume fraction and the number of particles in the 3D volume element. We suggest that using the statistically equivalent area fraction,introduced …

Structure-Property Relationship In Ionomer Membranes, Ahmet Kusoglu, Anette M. Karlsson, Michael H. Santare

Mechanical Engineering Faculty Publications

Perfluorosulfonic acid (PFSA) ionomer membranes are ion-conducting polymers with high water sorption capacity and thermo-mechanical stability. The morphology of PFSA changes during sorption affecting the mechanical and physical properties of the membrane. In this work, we investigate the structure-property relationship in swollen PFSA membranes using three proposed nanostructural descriptions and determine Young's modulus of the membrane at a wide range of temperatures (−20–85°C) and water volume fractions (0–0.5) for these configurations. Comparing the mechanics-based models with experimental data we propose that ion-rich water domains in PFSA membrane are spherical at low water content, spherical with connecting channels at intermediate water …

Modeling Disk Cracks In Rotors By Utilizing Speed Dependent Eccentricity, Andrew L. Gyekenyesi, Jerzy T. Sawicki, Wayne C. Haase

Mechanical Engineering Faculty Publications

This paper discusses the feasibility of vibration-based structural health monitoring for detecting disk cracks in rotor systems. The approach of interest assumes that a crack located on a rotating disk causes a minute change in the system’s center of mass due to the centrifugal force induced opening of the crack. The center of mass shift is expected to reveal itself in the vibration vector (i.e., whirl response; plotted as amplitude and phase versus speed) gathered during a spin-up and/or spin-down test. Here, analysis is accomplished by modeling a Jeffcott rotor that is characterized by analytical, numerical, and experimental data. The …

Design And Validation Of A General Purpose Robotic Testing System For Musculoskeletal Applications, Lawrence D. Noble, Robb W. Colbrunn, Dong-Gil Lee, Antonie J. Van Den Bogert, Brian L. Davis

Mechanical Engineering Faculty Publications

Orthopaedic research on in vitro forces applied to bones, tendons, and ligaments during joint loading has been difficult to perform because of limitations with existing robotic simulators in applying full-physiological loading to the joint under investigation in real time. The objectives of the current work are as follows: (1) describe the design of a musculoskeletal simulator developed to support in vitro testing of cadaveric joint systems, (2) provide component and system-level validation results, and (3) demonstrate the simulator’s usefulness for specific applications of the foot-ankle complex and knee. The musculoskeletal simulator allows researchers to simulate a variety of loading conditions …

Constitutive Response And Mechanical Properties Of Pfsa Membranes In Liquid Water, Ahmet Kusoglu, Yaliang Tang, Melissa Lugo, Anette M. Karlsson, Michael H. Santare, Simon Cleghorn, William B. Johnson

Mechanical Engineering Faculty Publications

The mechanical properties and swelling behavior of perfluorosulfonic acid (PFSA) membranes in liquid water have been investigated using a custom-built, temperature-controlled water bath. Interestingly, the theoretical models of Mooney-Rivlin and Ogden for rubber elasticity are shown to reproduce the major features of the experimentally obtained stress-strain relationships. In addition, stress relaxation of the membrane subjected to a fixed strain at room temperature fits time-dependent constitutive models used to describe nonlinear rubber elasticity. Thus, the experimental results suggest that even though PFSA is not an elastomer, the constitutive models developed for rubber-like behavior can be used for describing the ex situ …

A Computational Study For The Utilization Of Jet Pulsations In Gas Turbine Film Cooling And Flow Control, Olga V. Kartuzova

ETD Archive

Jets have been utilized in various turbomachinery applications in order to improve gas turbines performance. Jet pulsation is a promising technique because of the reduction in the amount of air removed from compressor, which helps to increase turbine efficiency. In this work two areas of pulsed jets applications were investigated, first one is film cooling of High Pressure Turbine (HPT) blades and second one is flow separation control over Low Pressure Turbine (LPT) airfoil using Vortex Generator Jets (VGJ) The inlet temperature to the HPT significantly affects the performance of the gas turbine. Film cooling is one of the most …

Thermal Analysis Of Natural Convectiona And Radiation In Porous Fins, Mehulkumar G. Maheria

ETD Archive

No abstract provided.

Heat Transfer In A Nanofluid Flow Past A Permeable Continuous Moving Surface, Sarvang D. Shah

ETD Archive

The main purpose of this paper is to introduce a boundary layer analysis for the fluid flow and heat transfer characteristics of an incompressible nanofluid flowing over a permeable isothermal surface moving continuously. The resulting system of non-linear ordinary differential equations is solved numerically using Runge-Kutta method with shooting techniques. Numerical results are obtained for the velocity, temperature and concentration distributions, as well as the friction factor, local Nusselt number and local Sherwood number for several values of the parameters, namely the velocity ratio parameter, suction/injection parameter and nanofluid parameters. The obtained results are presented graphically and in tabular form …

Natural Convection In A Porous Medium Saturated By Nanofluid, Kaustubh Ghodeswar

ETD Archive

A boundary layer analysis is presented for the natural convection heat and mass transfer flow past along two different geometries i.e., a vertical cone and an isothermal sphere in a Non-Darcy porous medium saturated with a nanofluid. A co-ordinate transformation is used to transform the governing equations into non-dimensional non-similar boundary layer equations. These equations are then solved numerically using implicit finite difference method (Keller-box method). Numerical solutions for heat transfer rate, mass transfer rate and friction factor have been presented for parametric variations of the buoyancy ratio parameter N-r, Brownian motion parameter Nb, thermophoresis parameter Nt and Lewis number …

A Comparative Study On Fault Detection And Self-Reconfiguration, Ning Ge

ETD Archive

Extended State Observer (ESO) and the Alpha-Beta-Gamma Tracker are introduced and compared. In comparison, the ESO is found to be more noise resistant. The extended state used for the estimation of the general system dynamics in real time makes it suitable for fault detection. Four control schemes are proposed for self-reconfiguration upon fault detection. These schemes are Active Disturbance Rejection Control, Tracker-based Feedback Control, Fuzzy Logic Control and Tracker-based PID Control. To compare their control performance, these schemes are applied to three different applications namely Active Engine Vibration Isolation System, Three-Tank Dynamic System and MEMS Gyroscope System. The advantages and …

Flow Induced Vibrations In Pipes: A Finite Element Approach, Ivan Grant

ETD Archive

Flow induced vibrations of pipes with internal fluid flow is studied in this work. Finite Element Analysis methodology is used to determine the critical fluid velocity that induces the threshold of pipe instability. The partial differential equation of motion governing the lateral vibrations of the pipe is employed to develop the stiffness and inertia matrices corresponding to two of the terms of the equations of motion. The equation of motion further includes a mixed-derivative term that was treated as a source for a dissipative function. The corresponding matrix with this dissipative function was developed and recognized as the potentially destabilizing …

Identification Of Unmodeled Dynamics In Rotor Systems Using Mu-Synthesis Approach, Ryan J. Madden

ETD Archive

It is well recognized that analytical models only approximate the true dynamics of analyzed rotating machines, due to the presence of components that are inherently difficult to model. Such models of rotating machines are driven by the best engineering knowledge and experience, and very often are updated based on experimental results. The problem of unmodeled or missing dynamics can be exacerbated in the presence of rotor structural damage such as a transverse crack on a shaft. This thesis will present an effective approach for model updating using advanced tools developed in robust control theory, specifically mu-synthesis. The methodology will be …

Opportunities For Lean Enterprise In Public Regional Transportation, Levent Baykut

ETD Archive

This thesis demonstrates the application of Lean Enterprise principles in a unionized/government-subsidized environment. This study states that Lean cannot be fully implemented in such an environment. The work environment and organization's culture required a hybrid system to maximize the process efficiency. Lean production is a manufacturing philosophy that focuses on adding value for the customer. It is commonly accepted that Lean is applicable to almost any repetitive process in any kind of organization, including government agencies and unionized work environments. The objective of this thesis was to research the opportunities and applicability for Lean Enterprise in public transportation. During the …

Value Stream Mapping Of Information Flow In Infrastructure Projects, Venkata Ramana Ramana Ari

ETD Archive

Value Stream Mapping (VSM) is a tool for depicting the flow of material in a manufacturing process. This study demonstrates that value stream mapping can also be applied to the movement and processing of information in a non-manufacturing environment. Here, the handling of, and changes to, water project construction plans within the Cleveland Division of Water (DOW) are tracked using value stream mapping. The map identifies opportunities for the Division of Water to streamline its processes and ensure that accurate information about project construction reaches its primary database in a timely fashion. Currently it takes about 19.1 weeks from the …

Numerical Investigation Of Mechanical Durability In Polymer Electrolyte Membrane Fuel Cells, Ahmet Kusoglu, Michael H. Santare, Anette M. Karlsson, Simon Cleghorn, William B. Johnson

Mechanical Engineering Faculty Publications

The relationship between the mechanical behavior and water transport in the membrane electrode assembly (MEA) is numerically investigated. Swelling plays a key role in the mechanical response of the MEA during fuel cell operation because swelling can be directly linked to the development of stresses. Thus, in the model introduced here, the stresses and the water distribution are coupled. Two membranes are studied: unreinforced perfluorosulfonic acid (PFSA) and an experimental reinforced composite membrane. The results suggest that open-circuit voltage operations lead to a uniform distribution of stresses and plastic deformation, whereas under current-load operation, the stresses and the plastic deformation …

An Analytical Model For Rotator Cuff Repairs, A. Aurora, Jorge E. Gatica, Antonie J. Van Den Bogert, J. A. Mccarron, Kathleen A. Derwin

Mechanical Engineering Faculty Publications

Background

Currently, natural and synthetic scaffolds are being explored as augmentation devices for rotator cuff repair. When used in this manner, these devices are believed to offer some degree of load sharing; however, no studies have quantified this effect. Furthermore, the manner in which loads on an augmented rotator cuff repair are distributed among the various components of the repair is not known, nor is the relative biomechanical importance of each component. The objectives of this study are to (1) develop quasi-static analytical models of simplified rotator cuff repairs, (2) validate the models, and (3) predict the degree of load …