Dynamic Stress-Strain Prediction of Vibrating Structures in Operation

University Of Massachusetts Lowell, Lowell MA

Investigators

Abstract

The research objective of this project is to integrate novel dynamic experimental measurements and computational modeling to predict the total spatial response and most importantly, how internal structural members respond to externally induced dynamic loads. For many complex composite structures (e.g. wind turbine, helicopter blades and other large flexible structures), mechanical failure is not externally apparent and typically occurs at the interfaces between the structure's surface and the internal ribs or stiffening members. Unfortunately, the interior dynamic response due to time-varying environmental, aerodynamic, and operating loads is not currently predictable from measured data. The proposed research will examine the use of analytical shape expansion functions for a large number of measured distributed points while rotating to predict interior dynamic stress-strain information at intricate joint interfaces, where failure often occurs. Such an approach will also enable the estimation of the externally applied distributed forces that are currently not measurable. The modeling approach can be applied to virtually any structure that has intricate joint interfaces by using a reduced number of measured degrees of freedom to interrogate or monitor a structure?s integrity. The proposed research is a new technology that will enable full-field dynamic measurement of rotating structures in operation, resulting in an improved understanding of the structural response of blades in flight. Both graduate and undergraduate students involved will gain an appreciation for current research areas important to industry and academia. The analytical tools can be used to create visually stimulating data that connects the effect of design decisions to the vibration response, and examples from music and sports can be tailored to the interest of different audiences to show how scientific research can contribute to our everyday lives. A strong outreach effort, building on previous successes, will be implemented using the animated image correlation data to motivate women and K-12 students to become interested in science and engineering.