Nonlinear Finite Element Analysis Of Natural Draught Cooling Tower

The natural draught cooling tower plays an important role in the operation of power plant. In china, the design of cooling tower is always based on Chinese code and the linear model is adopted. However, the result would be more consistent with actual situation when the nonlinear model is adopted, with the rapid development of nonlinear finite element theory and its widely used in the projects, it's significant to study natural draught cooling tower using nonlinear constitutive relation model.There are two major components in this thesis. In the first part, the commercial finite element analysis software ANSYS is used to calculate the stresses of the natural draught cooling tower using the linear model under wind,gravity and temperature loads. By comparing the results based on domestic and foreign codes, the value from foreign code is slightly less than that from the domestic one. Another part is about nonlinear finite element analysis. Considering two main RC constitutive models: ideal elasto-plastic model and Kent-Park model, the stress analysis and nonlinear stability analysis are conducted. The stress distribution on the two nonlinear models are given under standard and pressure and 28 times of the standard wind pressure, and compared with the results based on linear elastic model. Under standard wind pressure, the cooling tower is in elastic and the stress distributions based on three models are almost the same, however, there are obvious differences between linear and nonlinear models under 28 times of the standard wind pressure, for that some parts of the cooling towers have already been plastc state. Finally, the critical loads of nonlinear models are given which are similar with the results from linear analysis.