Study On The Mechanical Properties Of Conical Double Skin Concrete Filled Steel Tube Subjected To Compression And Tortion

As a new form of concrete filled steel structure,conical double skin concrete filled steel tube increasingly widely used in practical engineering,which makes it has important theoretical significance and practical value to study on the mechanical properties of conical double skin concrete filled steel tube.The paper study on the mechanical properties of conical double skin concrete filled steel tube subjected to compression and torsion from the theory,experiment and simulation,combined with previous relevant properties of conical double skin concrete filled steel tube subjected to compression and torsion and general concrete filled steel tube under compression and torsion,we recommended the practical calculation method for bearing capacity of the conical double skin concrete filled steel tube subjected to compression and torsion.The main contents including the following three aspects:It reveals that the failure mechanism of the conical double skin concrete filled steel tube under compression and torsion.Through Experiment we study on 10 conical double skin concrete filled steel tube failure modes and torque versus angular displacement curve of the whole process,found that the typical torque versus angular displacement curve can be divided into elastic stage,plastic stage and reinforced plastic stage.Establish and revise the finite element model simulated of the conical double skin concrete filled steel tubular actual working conditions.Using professional finite element software ABAQUS to simulate the working status of the conical double skin concrete filled steel tube under compression and torque,combined with the test failure mode results and the torque versus angle displacement curve to revise the whole process of the model so that the two results are consistent.In this way the founded reliable model can provide the foundation for numerical simulation.Study on the effect of the parameters on the conical double skin concrete filled steel tubular under compression and torque ultimate bearing capacity.The study found that taper、outer steel tube yield strength、sectional hollowness、inner tube diameter to thickness ratio,steel ratio etc.have a certain impact on the member bearing capacity and ductility.The nature reason is the material’s intensity and torsional moment of inertia,the greater of this two elements the greater of the ultimate bearing capacity and torsional stiffness of the member.On this basis,the method of calculate the compression and torsion bearing capacity of the conical double skin concrete filled steel tube was suggested.Based on the existing bearing capacity calculate method put forward the conical double skin concrete filled steel tubular capacity calculation formula.The experiments and numerical simulation indicate that the formula is correct and reasonable.