Matrix Analysis Method for Torsional Vibration of Composite Box Girders with Corrugated Steel Web
In order to accurately calculate the torsional vibration frequency of simply supported corrugated steel web composite box girders,on the basis of considering the shear deformation of corrugated steel webs,the principle of invariant value of dynamic potential energy and the"set-in-right-position"rule of forming a matrix are used to derive the element stiffness matrix of composite box girders during torsional vibration.Based on the derivation results,a program for calculating the torsional vibration frequency was written,and the calculation methods for the shear coefficient,effective shear modulus and torsional stiffness of the bridge structure were given.Subsequently,the effects of corrugated steel web type and shear deformation on the torsional vibration frequency were analyzed.The results show that the torsional vibration frequencies of the four types of simply supported corrugated steel web composite box girders commonly used in engineering are relatively close,and the influence of the corrugated steel web type on the torsional vibration frequency can be ignored in actual calculations;the influence of shear deformation on the torsional vibration frequency of simply supported corrugated steel web composite box girders is as high as 41.11%,and exceeds the influence on its bending vibration frequency.Therefore,the influence of shear deformation must be considered in practical engineering calculations.
corrugated steel webtorsional vibration frequencyshear deformationfree vibrationthe principle of total potential energy with stationary value
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