Fatigue performance analysis and experimental study of steel trusses integral joint based on multi-scale FEM

The fatigue performance of steel truss integral joint is analyzed based on multi-scale FEM. Numerical results are verified with experimental ones. The fatigue performance of steel truss integral joint is analyzed using a sea-crossing suspension bridge as its background. The 1:2 scale model fatigue test is taken. After 2e6 time load loops, the stress situation of integral joint is stable and fatigue performance is satisfactory for requirements. The multi-scale FEM, whose main researching part adopts three-dimensional elements while the connecting component adopts the common beam element, can reduce the computational cost. The  connection elements are used to connect the beam elements and  threedimensional elements. The connection element has two joints, one of which has six degrees of freedom, three translation degrees of freedom  and three rotational degrees of freedom, all degrees of freedom being  coupled. The multi-scale FEM and the experimental one yield very close results The multi-scale FEM can provide an accurate simulation of the main research part and ensure the fatigue life forecast so as to simplify the calculation. This method is high efficient and feasible. The multi-scale FEM provides a new and reliable method for the fatigue performance of structure analysis.