Shear Lag Of Composite Box Girder Under Transverse Load Displacement Effect Study

Due to the high efficiency,low energy consumption,and good mechanical properties of composite material laminated box girder,it has a good development prospect in the field of engineering construction.In order to ensure the stability and safety of the composite material laminated box girder structure during use,it is necessary to conduct a specific analysis of its mechanical properties.However,in the current academic literature on the theory of this type of box girder structure,it is generally believed that if the load of the box girder is not torsion,the load acts symmetrically on the ribs,then the top and bottom plates of the box girder will be Will produce the same shear lag effect law,and then calculate the shear lag effect.Although this can simplify some analysis and calculation processes,it ignores the actual forces of many structures.Often the position of the load on the composite box girder structure is random and uncertain,and when the position of its lateral action is different,it may also have a non-negligible impact on the shear lag effect,so the load is different.It is necessary to study the shear lag effect of composite laminated box girder under the lateral acting position.Based on the research of composite material laminated plate theory,this paper proposes an energy variational method for structural analysis of composite material laminated box girder considering the lateral displacement of load.Different longitudinal displacements are used for the top and bottom plates of the composite box girder.Difference function,the theoretical analytical solution of the shear lag effect is derived,and the specific load model is analyzed.This article mainly focuses on the theoretical study of the shear lag effect of composite laminated box girder.In addition,under different working conditions,considering the influence of the ply angle,the positive and negative shear lag effects of the carbon fiber laminated box girder with different laying schemes under the load lateral displacement were numerically simulated,and the indoor simulation test was carried out in some cases.,Through comparative analysis to get the correct conclusion.The main research work and results of this paper are as follows:(1)Based on the energy variation method,a more realistic cubic parabolic equation is used as the longitudinal displacement difference function of the composite laminated box girder.Considering the lateral displacement of the load,the analytical theoretical solutions for the shear lag effect of the top and bottom plates of the composite laminated box girder are deduced.(2)Several common load-bearing models of composite box girder are calculated and analyzed.The law of shear lag effect changes considering the lateral displacement of load is obtained,which enriches the shear lag theory of composite material laminated box girder.(3)The finite element software ANSYS is used to carry out numerical simulation calculations for the carbon fiber laminated box girder under different laying schemes,and the shear lag coefficients when the load acts on the top plate of the box girder transversely at different positions under different working conditions are calculated,and the numerical simulation results Compared with the theoretical calculation results,the theoretical derivation of this paper is verified.(4)By manually making carbon fiber laminated box girder with different laying schemes indoors,part of the simulated loading test is carried out,and the test results are compared with the previous calculation results.