# A Review of the T-Stub Components for the Analysis of Bolted Moment Joints
## 4 Numerical Models
The main conclusion of this study was the following: The FE analysis of the T-stub showed that the bending in the bolt starts since the beginning of the load. When the bending load is taken into account, the ultimate resistance of the bolt is reached. In the contrary case, the bolts reach about 70% of their ultimate resistance. The increase in T-stub flange thickness leads to the decrease in the value of the bending moment in the bolts that will, therefore, develop their ultimate resistance. In 2015, [PERSON] et al. [72], because of the lack of information to predict the ductility of T-stubs connection in the codes such as EC3 [1], developed a simplified 2D FEM model of a bolted T-stub, with only one bolt row, in the widespread commercial software SAP2000 to estimate the plastic deformation capacity. This model was made by using beam elements. The calibration of the FEM model was done with experimental data of specimens tested at the Material and Structure Laboratory of Salerno University in 2001. The authors concluded that the 2D FEM model is accurate enough to predict the stiffness and resistance and the plastic deformation capacity. Furthermore, it allows of been developed in commercial software such as SAP2000. In 2016, [PERSON] et al. [14] studied the behaviour of T-stubs connected with clamps by changing the clamp geometry. This type of connection has the advantage of been dismountable and reconfigurable. Nevertheless, the information that could be found in the literature about it was insufficient. Therefore, a FEM model was established to validate an analytical model that could predict the behaviour of clamp joints. This new method is based on the EC3 method. The calibration of the FEM model was performed against experimental tests results (T-stubs obtained from IPE220 profiles), and the most highlighted of the simulation was the used of tetrahedral finite elements (see Figure 29b) for meshing the T-stub and the clamps. The results of the investigation (IPE220 experimental, FEM analytical and HEA200 analytical and FEM) showed that the proposed method was suitable for analysis this type of connection, depending of the geometry parameters of the clamps (lever arms). According to this, a greater front lever \"a\" (see Figure 29a) of the clamp improves the T-stub behaviour and impair the bolt behaviour. Besides, the increment of the rear lever \"b\" (see Figure 29a) reduce the axial force in the bolt. Moreover, the comparison of the analytical results and the FEM simulations showed that the analytical model values were 10% lower than those found in the FEM. In 2016, [PERSON] et al. [73] studied the response of T-stub connections under impact loads. This assessment was developed by means of the finite element method. In the FEM model, the T-stub assembly was simplified by employing symmetry conditions, and it was composed of a rigid base, the T-stub (flange), the bolt (the head, shank, nut and washer), and the pulled-out plate (web). The constitutive law of the material is enhancement due to the impact load condition. This increment of the constitutive law is obtained by adopting the dynamic increase factor (DIF), which basically gives the relation of the dynamic  
Figure 29: Clamp T-stub: (**a**) Geometric parameters; (**b**) Tetrahedral mesh [14]. “Reproduced with permission from [PERSON], Journal of Constructional Steel Research; published by Elsevier, 2016”. strength to the strength obtained under static conditions. The principle of Hooputra [74], which is included in the ABAQUS software package, predicts the failure of the FEM model. This model assumed that two main relevant mechanisms induced fracture of a ductile metal: ductile fracture due to nucleation, growth and coalescence voids and the shear band localisation cause the shear fracture. The authors considered only the ductile fracture for the investigation, and the [PERSON] criterion was adopted. The validation of the FEM models was done against quasi-static experiments performed by [PERSON] et al.