Analysis Of Vehicle Dynamic Characteristics Of Steel-Concrete Composite Girder Bridges

Compared with traditional concrete beams and steel beams,steel-concrete composite beams have excellent structural properties and are therefore widely used.At the same time,since the 20th century,railway traffic has developed rapidly,and the railway's transportation capacity and operating speed have increased significantly.Therefore,the research on the dynamic performance of steel-concrete composite beams is becoming more and more important.Based on this,the following research is mainly carried out:(1)The steel-concrete composite beam is deduced and analyzed considering the interface slip self-vibration characteristics.The vibration equation and its boundary conditions of the composite beam considering the interface slip are obtained,and the analytical solution of the natural vibration frequency is solved.After that,through a specific example,use ANSYS to compare modeling operations with formula operations.Get conclusion:In the low-order mode,the difference between the formula calculation result and the ANSYS operation result is small,and the accuracy of the formula is verified.(2)Establishing a numerical model for finite beam element considering the interface slip and shear lag effect of composite beam.Compared with the Euler beam model,the composite beam model can additionally consider the interface slip,the shear lag effect of the concrete slab and the shear lag effect of the steel box girder.Based on this model,the stiffness matrix and the consistent mass matrix of the composite beam are derived.(3)Based on the development of the composite beam numerical model,the vehicle motion equation,the bridge motion equation and the total motion equation of the axle are established.And use Matlab software to write the axle program.(4)Using the completed axle program,the vertical dynamic response of composite beams under different train speeds,the vertical dynamic response of composite beams under different trains,the vertical dynamic response of composite beams under different shear stiffness and the vertical dynamic response of the composite beam under different cantilever lengths of concrete slabs are calculated.Through the above calculations,the dynamic characteristics of the composite beam are objectively described and analyzed,which provides a reference for the steel-concrete composite beam structure design and train operation speed.