Study On Impact Resistance Of Tubular K-joint With Inner-stiffened Ring Under Pre-axial Perssure In Chord

The steel tubular structures have been widely used owing to its advantages of light quality,high strength and good building effect.The tubular intersecting joint is an important part of the whole structure.At present,the researches on the static mechanical properties of steel tubular structure are very mature,while,the impact of steel tubular structure during the service process,such as impact,explosion,etc.often occurs.There are a few studies on the impact resistance of steel tubular structure at home and abroad.Most of impact studies targeted common joints,and ignored the axial forces that exist in the structure during the service process.The reinforcement methods such as inner-stiffened ring in the joint can improve the material utilization and impact resistance of the structure,which is of great significance to engineering applications.The main study aspects are listed as follows:Axially preloaded tubular K-joints under impact load are tested,comparing to the failure mode,impact force,displacement,strain and residual deformation of ordinary joints and inner-stiffened ring reinforcement joints.The results show that the inner-stiffened ring can significantly improve the impact resistance of the joint and change its damage mode.FE numerical analysis software ABAQUS was used to simulate the test steel tubular joints comparing with others and the impact test data of this paper,the results show that the impact force,displacement,strain,etc.of the output of the FE model agree well with the test,which proves that the model is reasonable and effective,providing the conditions for the following mechanism analysis and parameter analysis.Using the powerful data output capability of the FE software ABAQUS to analyze the energy dissipation,impact force,displacement,deformation of the inner-stiffened ring,and the stress map of the chord,brace and inner-stiffened ring,aiming to explain the effect of the inner-stiffened ring on the energy dissipation of the K-joint,the bearing capacity of the impact resistance of the joint,and the mutual influence of the stiffening rings in different positions.The yield strength of steel,the number and size of stiffening rings,and the height of drop hammer were compared and analyzed using FE software to reveal the impact of different parameters on the impact resistance of axially preloaded tubular K-joint.