# A Review of the T-Stub Components for the Analysis of Bolted Moment Joints
## 4 Numerical Models
The calibration was performed in ABAQUS code on test data results, and the parameters that were considered are: the influence of the brick element type (C3D8, C3D8R, C3D8I), the influence of friction coefficient between the flange and the foundation (mu = 0, mu = 0.25 and mu = 0.5) and the bolt model influence (3D model and spin model). As a result of the simulations, they concluded the following:  
* The C3D8I element reproduces the behaviour of the T-stub connection more precisely. * The friction coefficient affects T-stub responses only on the large displacement regime. * The spin bolt model with two beam elements gives more accurate results than the model with only one beam element when the models are compared with the results of the 3D bolt model. The same year, [PERSON] [63] proposed a numerical FE 2D model capable of describing plasticity, large displacement and unilateral contact effects. The simulation results (force-displacement curve) showed that they had not achieved a good agreement with the experimental curve. However, the simulations were improved by changing the constitutive law of the material because no data for the ultimate stress value was available. In 2002, [PERSON] studied the behaviour of T-stub connections [64] employing a robust FE model. These simulations were intended to supplement the experimental part of the research work and provide insight into the T-stub behaviour and the stress distribution. The simulation results were used as a point of comparison to validate a 2D finite element model. Moreover, the authors analysed the bolt responses (different pretension loads) and the drying effect. Even though the simulations reached a good agreement with experimental results, the material law of the T-stub had been considered with nominal values because the material characterisation had not been done until the FE model was finished. Therefore, this procedure is considered questionable. In 2003, [PERSON] and [PERSON] [65] performed an analysis of the influence of the equivalent bolt length in finite element modelling of T-stub steel connections. The simulations were performed in the software MSC/Nastran and calibrated with experimental data obtained from the experimental tests of the T-stub labelled as T1 and T2 of the [PERSON] and Bursi investigation [4]. Because of a significant lag in the maximum displacement observed in the calibrated simulations, a parametric analysis was performed by changing the bolt length, which was initially determined by Aggerkov's expression. The parametric study showed that the required correction in the bolt length is heavily dependent on both the applied preload level and the developed failure mechanism. For instance, for the non-preloaded T-stub T1, the experimental displacement was reached when the bolt length increased by 50% or for the preloaded T1, the experimental displacement was reached when the bolt length increased by two times. In 2004, [PERSON] et al. [66] did a finite element model to study the non-linear behaviour of bolted T-stub connections, which is the component that idealises the tension zone of the end-plate connection. The simulations were performed in two different T-stub connections: rolled profiles cut along the web and two plates, flange and web, welded to each other in a T shape with a continuous fillet weld. The experimental test results, which were aforementioned in the experimental testing section, were used to calibrate the simulations. The results of these simulations unveiled that the FEM of the rolled T-stub, see Figure 26a,b, reproduced accurately the behaviour of the connection. However, the fillet-welded T-stub simulations showed that the difference between numerical and experimental results was considerable due to the residual stresses and the modified material properties close to de welded toe (HAZ). Therefore, to reproduce the T-stub behaviour more accurate, the material properties were softening around 20% in the HAZ zone in the numerical simulations, see Figure 26d.