| Summary: | 碩士 === 國立中興大學 === 土木工程學系 === 90 === ABSTRACT
In the study of dynamic structures , it is necessary to prevent resonant phenomenon to occur . This thesis is devoted to the dynamic analysis of mult-span frame . Initially we can establish equations of motion by classical dynamic equilibrium method to a uniform beam . Then , by using direct stiffness method to derive the dynamic stiffness matrix of the beam . Afterword we combined each beam stiffness matrix accord -ing to boundary conditions and force equilibrums to derive the dynamic stiffness matrix of frame . After finding the dynamic stiffness matrix of frame , then we can obtain the natural frequencies of frame .
Two sets of beam theories are applied to derive motion equations of beam . The first set of equations is obtained on the basis of Bernoulli - Euler beam theory . The other set of equations is established on a Timoshenko beam theory inclouding axially compression force .
Finally , a two-span frame taking as an example . With different cross - sectional shapes K , lengths of beam L , slenderness ratios 1/r , cross - sectional areas A , depths of beam H and axial loads N to analysis the possible influence of vibration of frame .
|
|---|
