Elastic-plastic dynamic analysis of steel structures under random vibrations excited by the wind.

Author(s)

Estevão Carcioffi Lazanha

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Escola Politécnica (EP/BC)
• Defense date: 2003-01-30

Examining board members

Reyolando Manoel Lopes Rebello da Fonseca Brasil; Mario Franco; João Alberto Venegas Requena

• Advisor: Reyolando Manoel Lopes Rebello da Fonseca Brasil

Abstract

This work presents a numerical model to analyze structures under random dynamic excitation induced by the wind. The structure is considered to have nonlinear behavior due to the elastic-plastic constitutive law adopted for the material, structural steel. The members of the studied structures may experience formation or disappearance of plastic hinges, leading to a more economic design. Random vibrations of linear structures is a well established subject. On the other hand, very few results are available for the nonlinear case as the one considered. To simulate random vibrations a Monte Carlo type analysis is used. A power spectral density function for wind velocity is used to generate a large number of harmonic input functions. Their phase angles are generated via a pseudo-random algorithm. Numerical time integration using Newmark’s method is performed for each input function. The large amount of response data obtained is statistically treated to allow for useful engineering conclusions on the probability of occurrence of unfavorable events. (AU)