Numerical studies on dynamic behavior of tubular T-joint subjected to impact loading

• A FE model was proposed and validated by the experimental results.
• Global and local deformation of the structure under impact loading was determined by equal area axial method.
• The failure mechanism of steel tubular T-joints under impact loading was investigated based on the FE modeling and test results.
• An equivalent impact force estimation method based on reciprocal theorem of work was proposed.

Joints play an important role in resisting impact loading in Tubular structures. In this paper, a finite element model validated by experimental results is developed to numerically study the failure modes and energy dissipation mechanism of tubular T-joint impacted by a drop hammer with the initial velocity of 7–10 m/s. The resistant mechanism is investigated based on the dynamic responses of the joints under impact loading. Strain, displacement and the failure modes of the T-joints are also predicted. Global and local deformations of the tubular joints are distinguished using an equal area axis method, which helps to discover the failure mechanism of the joints. Using the yield line theory, an equivalent impact force estimation method is also proposed based on the impact load versus displacement relationship. The numerical analysis and the simplified method provide a basis for impact resistance evaluation and progressive collapse mitigation of steel tubular structures in design practice in the future.