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Document Type

Open Access

Degree Program

Mechanical Engineering

Degree Type

Master of Science in Mechanical Engineering (M.S.M.E.)

Year Degree Awarded

2012

Month Degree Awarded

September

Keywords

fluid-structure interactions, wind, trees, nonlinear, structural, dynamics

Abstract

Ambient wind causes trees to oscillate. Wind-induced oscillations of trees constitute a fluid-structure interaction problem, which has been studied by many researchers from various points of view. However, there is yet a lot to be done. From an engineering point of view, the complex structure of trees, which are very different from man-made structures, as well as the highly nonlinear interaction between wind and tree, makes it a challenging task to predict the amplitude and frequency of the resulting oscillations. From a biological point of view, the influence of wind on photosynthesis as well as the growth and death of plants is crucial. A nonlinear model is derived for wind-induced oscillations of trees to investigate the effect of structural nonlinearities. It is shown that the structural nonlinearities in the system can result in a hardening behavior of the tree, indicating the importance of taking such nonlinearities into account. The influence of various system parameters such as tree’s age, taper and slenderness ratio on the tree oscillations is studied using this nonlinear model.

First Advisor

Yahya Modarres-Sadeghi

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