Mechanical Engineering Commons^™

Implementation Of Analytical Fatigue Models Into Opensim To Predict The Effects Of Fatigue On Anterior Cruciate Ligament Loading, Michael A. Samann

Mechanical & Aerospace Engineering Theses & Dissertations

The anterior cruciate ligament (ACL) provides stability to the knee joint while performing activities such as a side step cut. Neuromuscular fatigue, a reduction in muscle force producing capabilities, alters lower extremity mechanics while performing a side step cut and may increase the risk of ACL injury, particularly in females. Musculoskeletal modeling allows for the measurement of muscle forces, which are difficult to measure in-vivo. Therefore, musculoskeletal modeling, may improve our understanding of the effects of neuromuscular fatigue on muscle force production and loading of the ACL. Therefore, the purpose of this study was to develop a musculoskeletal model which …

Prediction Of Tribological Behavior Of Candidate Materials For Rotor Seals, John W. Franzino, Will F. Michul

Materials Engineering

To reduce high costs associated with manufacturing and testing materials for rotor seals, a procedure needs to be developed to quickly and accurately test candidate materials as they are released. The test should reduce the amount of fabrication required and model working conditions in order to accurately assess the tribological behavior of candidate materials. A possible solution was examined that utilized a rig meant to model operational stresses and wear. Compression modulus data was then taken in order to quantify the accumulation of damage due to microcracking, the primary mode of failure, through a damage index parameter. Testing results concluded …

A Practical Tool For The Determination Of Surface Stresses In Railroad Bearings With Different Contact Geometries And Load Conditions Using Finite Element Analysis, Michael A. Mason

Theses and Dissertations

The connection between contact geometry and fatigue in tapered roller bearings utilized in the railroad environment is still of interest. Roller bearings for railroad applications are typically precision ground with crowned contact geometries to prevent edge loading of components. This normally results in completely elastic Hertzian contact stresses under standard railcar loads. However, under extreme load conditions, detrimental edge loading has been known to occur. It is proposed to develop a tool, using finite element analysis, that can be utilized to optimize complex raceway crown geometries for severe applications.

A successful implementation of this tool is presented and validated using …

Energy Dissipation And Entropy Generation During The Fatigue Degradation: Application To Health Monitoring Of Composites, Ali Kahirdeh

LSU Doctoral Dissertations

In this dissertation, an experimental approach for characterizing energy dissipation and degradation evolution in a woven Epoxy/Glass (G10/FR4) laminate subjected to fully reversed bending fatigue test is presented. Infrared thermography and acoustic emission are utilized to characterize the degradation progression. The results show similar evolutionary response indicating the presence of three degradation stages. The effect of the surface cooling on the fatigue life of the laminates is investigated both experimentally and analytically. The results show that the life of the laminate is highly dependent on the temperature and that surface cooling can significantly increase the fatigue life of the laminate. …

Evaluation Of Forearm Muscle Fatigue From Operating A Motorcycle Clutch, Megan O. Conrad, Richard W. Marklin

Mechanical Engineering Faculty Research and Publications

A laboratory experiment evaluated the effect of motorcycle clutch design on the electromyography (EMG) activity of the primary agonist finger flexor muscle in the forearm. The goal was to compare muscle fatigue resulting from operation of two different motorcycle clutches in simulated traffic. EMG activity from the flexor digitorum superficialis (FDS) muscle of 12 female and 11 males were recorded while each participant operated an existing motorcycle clutch (requiring 98 N peak force) as well as an alternate design (requiring 36 N peak force) during 60-minute simulations. Muscle fatigue was quantified by measuring the decrease in median frequency of the …

An Experimental Investigation Of Corrosion Fatigue Life Via Thermographic Method, Richard Wayne Purvis

LSU Master's Theses

The effect of prior corrosion fatigue damage on the thermographic response of 1018 low carbon steel is investigated. Specimens were subject to rotating bending fatigue at 38 Hz loading frequency while being exposed to a 3.5% NaCl and distilled water solution. Some specimens were subject to corrosion fatigue for part of their fatigue life and then their thermographic response measured under fatigue in air at 62 Hz loading frequency. Fatigue tests in air with thermographic measurement were performed as a comparison. It was observed that the initial temperature rise after corrosion fatigue fits the previously proposed model for air fatigue, …

Using A Sleep And Activity Monitor To Operationalize Fatigue Risk Management, Vanessa Bégat Seitz

LSU Master's Theses

When a person continues to work despite being fatigued, an accident may occur or productivity may decrease. Reducing fatigue related accidents is complicated due to the subjective nature and pervasiveness of the feeling of fatigue. Because finding one universal definition or measure of fatigue is problematic, fatigue is typically measured by a combination of factors such as amount of sleep obtained, physical or cognitive work performed, or sleepiness which can then be related back to a measure of performance. Until recently, sleep measurement was restricted to a lab setting; however, with the emergence of actigraph devices, it is now possible …