# A Review of the T-Stub Components for the Analysis of Bolted Moment Joints
## 6 T-Stubs of Non-Conventional Steel and Other Materials  
In 2000, [PERSON] et al. [84] focused on the study of the behaviour of aluminium T-stubs. Thus, the authors carried simulations that were calibrated with available data from the literature. At that moment, no experimental tests on aluminium T-stubs were carried out; thus, the 3D eight nodes (C3D8R) FEM model was calibrated with experimental data of steel T-stubs. The numerical analyses showed a wider range of failure mechanism for the aluminium T-stubs than steel T-stub. Failure mode 2 was divided into three. Furthermore, the HAZ effect was taken into account because, for some aluminium alloys, the mechanical properties are softening by 50% due to welding. The simulations result that did not consider and considered the HAZ were compared. This comparison showed that the strength of the material was reduced. The analysis also showed that the collapse mechanisms were not different from the steel T-stub. In 2006, [PERSON] et al. [85] studied the hysteresis behaviour of T-stub connections using shape memory alloy (SMA), where the tee and the bolts were SMA, by comparing the results with the behaviour of steel T-stubs. The investigation was performed in two phases: phase I was focused on determining the optimum heat treatment temperature to establish a superelastic effect. Therefore, the material was heat-treated at 300 \({}^{\circ}\)C and 350 \({}^{\circ}\)C and three different testing protocols were employed: (1) monotonic tensile testing; (2) cyclic testing, and (3) Tensile testing of the cycled parts. Phase II tested cyclic T-stubs connection made of SMA and steel. The optimum temperature determined in phase I was employed to treat the SMA fastener of phase II. The comparison of the experiments showed that the energy dissipation of T-stub with SMA fastener was higher than those obtained with steel material for the particular stress level under consideration. The steel test was stopped when it reached the same stress level that the SMA specimens developed, which failed in early stages of loading at 28 th and 22 nd strain cycles. In 2006, [PERSON] and [PERSON] [86] studied the behaviour of aluminium weld T-stubs with different geometrical configurations and material properties. The T-stubs were obtained by welding together three different wrought aluminium alloys, which are AW 6061 (t = 10 mm), AW 6082 (t = 12 mm) and AW 7020 (t = 12 mm). 26 T-stubs were obtained by combining the different available materials and were tested under a monotonic load and a cyclic load. Afterwards, the results of the monotonic tests were compared with the analytical k-method (found in EC9) and with the EC3 method. This comparison showed that many factors such as the geometrical, mechanical and factors as the parasitic bolt bending, effects of the HAZ affect the prediction of the behaviour of the analytical method. Despite the things mentioned, the analytical k-method can be considered fairly reliable, conservative and suitable for design purposes due to its simplicity. Moreover, it was determined that the appropriate choice of mechanical parameters the values of strength predicted with the k-method are always on the safe side. In 2009, [PERSON] et al. [87] studied the behaviour of aluminium welded T-stubs under monotonic loads. The investigation was focused on developing a FEM model capable of reproducing the behaviour of the T-stub. Therefore, 26 experimental tests [88,89] with different geometries (flange thickness, bolt number and distribution), three different heat-treated wrought aluminium alloys (AW 6061-AW 6082-AW 7020), and three types of bolts (aluminium and steel bolts) were employed to calibrate the model. This numerical model used hexahedral elements (C3D8R) for the T-stub and tetrahedral elements for the bolts. Additionally, the constitutive law of the heat-affected zone and the unheated-affected zone of materials were introduced as a multi-linear curve in the simulation.