Based on the transfer matrix method, an analytical method is proposed to conduct the modal analysis of the simply supported beam with multiple cracks under high temperature. In the modal analysis process, transverse cracks are replaced with torsion springs without mass, and local flexibility of each crack is derived; The temperature module is introduced by the change of the mechanical parameters of the structural material, and considering the axial load of the simply supported beam caused by the variation of the temperature, the transfer matrix of the whole cracked beam with the temperature parameter, the number and geometric parameters of cracks is obtained. According to boundary conditions of the simply supported beam, natural frequencies of the simply supported steel beam with multiple cracks is calculated. Results indicate that the influence of the axial temperature load on natural frequencies of the simply supported steel beam is very large, and it can not be ignored; The increase of the temperature can significantly decrease each order natural frequency of the cracked simply supported steel beam; the first order natural frequency and critical temperature of the cracked simply supported steel beam gradually decrease as the relative depth of cracks increases.
Key words
high temperature /
temperature load /
multiple cracks /
simply supported steel beam /
natural frequency
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