Study On Shear Behavior Of Cold-formed Thin-walled C-shaped Beams

The cold-formed thin-walled steel C-shaped beam,as a common flexural component,is mainly subjected to shear force when the span of C-shaped beam is slightly small or it is the short beam.Based on the cold-formed thin-walled steel C-shaped beam tests,many parametric studies were performed through the finite element method which was verified to be valid.Finally the shear stress of cold-formed thin-walled steel C-shaped beams was converted.Hence,the calculation formula of shear bearing capacity of cold-formed thin-walled steel C-shaped beams was proposed.Firstly,this paper briefly introduced the shear test of cold-formed thin-walled steel C-shaped beams,including test specimens,test device,loading system,failure characteristics of specimens,load-displacement curves and shear capacity.Secondly,the finite element software ABAQUS is used to simulate the shear behavior of the tested specimens.The finite element model(FEM)was established according to the tests.Then,the results of FEM,including shear bearing capacity,load-displacement curves and failure characteristics,were compared to those of the tests.It is showed that the results of FEM are in good agreement with the experimental results and the developed FEM was capable of simulating the behavior of cold-formed thin-walled steel C-shaped beams.Then,the parametric studies about shearing behavior of cold-formed thin-walled steel C-shaped beams were conducted on the basic of the finite element model verified the correctness and feasibility.The parameters mainly include the ratio of height to thickness of web,the thickness of web,the shear span ratio of beams and the yield strength of materials.What can be found that the web thickness has the greatest impact on the flexural bearing capacity and the deformation of cold-formed thin-walled steel C-shaped beams.With the increase of the web thickness,the bearing capacity and stiffness of cold-formed thin-walled steel C-shaped beams increases significantly.However,while the web thickness was too thin,the distortional buckling of the C-shaped beams will occur.In addition,the shear bearing capacity of cold-formed thin-walled steel C-shaped beams will be greatly improved by increasing the ratio of web height to thickness.The change of shear span ratio of cold-formed thin-walled steel C-shaped beams is mainly affected by the failure characteristics of cold-formed thin-walled steel C-shaped beams.With the shear span ratio of cold-formed thin-walled steel C-shaped beams increasing from 0.5 to 2,the failure characteristics are changed from shear yield failure to shear failure.The shear strength of the cold-formed thin-walled steel C-shaped beams is greatly improved by the increase of the strength of the steel,but the variation of the steel strength has little effect on the stiffness of the cold-formed thin-walled steel C-shaped beams.Finally,based on the analysis of variable parameters,the shear stress of the web under different conditions was modified well,considering the effects of flange and clipping of cold-formed thin-walled steel C-shaped beam.According to the stress state,the calculation formula of the shear capacity of cold-formed thin-walled steel C-shaped beams was divided into three parts,which included the calculation formula of shear yielding capacity,elastic shear buckling capacity and inelastic shear buckling capacity.The theoretical calculation was verified to be valid by comparing the results of the theoretical formula to the results of the FEM and the tests,which can provide a design method for the calculation of the shear capacity of cold-formed thin-walled steel C-shaped beams.