Analysis and fracture behavior of welded box beam-to-column connections considering residual stresses

- Develops finite element models for simulating welding.
- Evaluates three heat source models.
- Conducts cyclic tests on welded box beam-to-column connections.
- Evaluates the effect of residual stresses on the fracture behavior of connections.

This paper investigates the effects of residual stresses on the fracture behavior of welded box beam-to-column connections. Finite element analyses are first conducted to evaluate three commonly used heat source models for simulating welding. The selected models are the volumetric heat generation rate model, Gaussian model, and double ellipsoidal model. The evaluations indicate that the volumetric heat generation rate model has the best performance. Experimental tests on two welded box beam-to-column connections are then conducted to evaluate their fracture behavior when subjected to cyclic loading. The test results show that the governing failure mode is the fracture of the weld at the beam flange. Finally, additional finite element analyses are conducted to evaluate the effects of residual stresses on the fracture behavior of the two tested connections. The analyses indicate that welding residual stresses result in the increase of equivalent plastic strain at the welds, which will lead to earlier fracture of the connection.