Stressing State Analysis Of Dumbbell Arch Model Based On Numerical Shape Function Method

Concrete filled steel tubular(CFST)arch bridge with dumbbell section is widely used in various sections of CFST arch bridges for its outstanding bearing capacity,convenient construction process,strong spanning ability and beautiful appearance.Although many universities in China have carried out theoretical and experimental research on CFST structures,most of the current researches tend to concentrate on single circular tube arch and the researches on dumbbell arch ribs are relatively less.The out-of-plane stability of CFST arch has always been the key point of research.The instability of arches results from both material non-linearity and geometric nonlinearity.It is difficult to distinguish the instability damage and the strength damage.Therefore,the theory of structural stressing state is proposed to establish a unified failure criterion,incorporating these two failure modes into one framework.It pays attention to the essential feature of the change of structural stressing state,i.e.failure state,which updates the definition of structural failure load and determines the quantitative calculation index of structural performance at various load levels.However,there are many hypotheses in applying the theory of structural stressing state to process the experimental data,and the explanation is far-fetched.In order to fully and thoroughly investigate the changing characteristics of structural stressing state,a new interpolation method is needed to assist the study.But the conventional interpolation methods have unclear physical meaning and unsatisfactory interpolation accuracy.Therefore,this paper proposes a new spatial interpolation method based on numerical simulation,fully considering the physical model information behind the experimental data to improve the interpolation accuracy.The validity of the numerical shape function(NSF)method is verified by the quasi-real model considering load uncertainty and material defects.The results show that the method has good interpolation performance and broad development prospects.In this paper,using the theory of structural stressing state,the data of CFST arch ribs with dumbbell section are modeled for further analyzing,and the failure characteristics of the structure during the process of bearing are revealed,including the structural overall failure characteristics,the submode characteristics of various components of the structure and various internal forces,verifying the structural failure criteria at the same time.Moreover,the ANSYS software is used to simulate the CFST arch bridge model with dumbbell section.Compared with the measured experimental values,the advantages and disadvantages of the conventional simulation could be displayed.However,the differences between the simulation results and the experimental data are inevitable,so it is necessary to investigate the interpolation method.The strain fields are obtained through applying the NSF method to experimental data,then the axial force and bending moments of the cross section can be gotten by the numerical integration of the constitutive equation of the materials.It is easier to grasp the structural working performance from a more precise internal force level,in order to further verify and reveal the regular working characteristics of the structure in the process of loading,enriching the theory of structural stressing state.In a word,Based on this research,it can enrich and develop the theory of out-of-plane force research of CFST arch,and provide effective suggestions for the optimization of engineering design.