Primary Faculty Mentor Name

Eric Hernandez

Status

Graduate

Student College

College of Engineering and Mathematical Sciences

Program/Major

Civil Engineering

Primary Research Category

Engineering & Physical Sciences

Presentation Title

Monitoring Stress Reactions in High Mileage Runners Within a Mechanical Fatigue Framework

Time

9:00 AM

Location

Silver Maple Ballroom - Engineering & Physical Sciences

Abstract

Fatigue is the degradation of a structure due to the repeated application of cyclic stresses, even if the applied stress is below the material’s yield strength. It has been estimated that 90% of mechanical and structural service failures can be attributed in one way or another to fatigue. Railroad cars, aircraft fuselages and wings, automobiles, oilrig platforms, and wind turbines are all susceptible to fatigue failures. These failures are not only confined to structural systems but also biological systems, such as with stress fractures and overuse injuries in runners. Each year nine out of ten runners will sustain an exercise related injury.

We propose that a fatigue monitoring framework that has been previously applied to a structural system can be extended to a biomechanical system. A spring-mass-damper model and a minimal number of sensors will be used to estimate the dynamics, specifically ground reaction forces, of the biological system during a run. The methodology uses an Extended Kalman Filter to estimate local stress fields, model stiffness, and model damping based on global acceleration measurements. A fatigue monitoring framework is used to perform stress cycle counting along with a corresponding S-N curve to quantify the remaining useful life through a mechanics-based damage index in near-real time. The proposed SHM framework can minimize the risk of injuries and its associated cost, and if proper actions are performed, it should help to prevent or delay stress related injuries.

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Monitoring Stress Reactions in High Mileage Runners Within a Mechanical Fatigue Framework

Fatigue is the degradation of a structure due to the repeated application of cyclic stresses, even if the applied stress is below the material’s yield strength. It has been estimated that 90% of mechanical and structural service failures can be attributed in one way or another to fatigue. Railroad cars, aircraft fuselages and wings, automobiles, oilrig platforms, and wind turbines are all susceptible to fatigue failures. These failures are not only confined to structural systems but also biological systems, such as with stress fractures and overuse injuries in runners. Each year nine out of ten runners will sustain an exercise related injury.

We propose that a fatigue monitoring framework that has been previously applied to a structural system can be extended to a biomechanical system. A spring-mass-damper model and a minimal number of sensors will be used to estimate the dynamics, specifically ground reaction forces, of the biological system during a run. The methodology uses an Extended Kalman Filter to estimate local stress fields, model stiffness, and model damping based on global acceleration measurements. A fatigue monitoring framework is used to perform stress cycle counting along with a corresponding S-N curve to quantify the remaining useful life through a mechanics-based damage index in near-real time. The proposed SHM framework can minimize the risk of injuries and its associated cost, and if proper actions are performed, it should help to prevent or delay stress related injuries.