## 4 Finite Element Analysis Results and Discussion  
### Average Shear Stress in the Critical Section  
Most current building codes consider that damage occurs when the shear force in the critical section of the slab exceeds the load-carrying capacity of the slab. Except for Eurocode 2 [21], most design standards take the location of the critical section to be at a distance of d/2 from the column surface. When damage occurs outside the reinforcement zone, \(b_{out}\) is the perimeter from the position of the outermost shear reinforcement d/2 (Figure 21). However, the experimental specimens in this paper take only the critical section shear stress on the eccentric force side into account. Only the slabs with M/V = 0 (i.e., S1, S2, and S7) and M/V = 0.27 (i.e., S3, S4, and S8) were tested in the experiments of [PERSON] et al. The numerical simulation in this paper was carried out by adjusting the forces applied to the four sides of the plate to achieve different moment-to-shear ratios (M/V = 0.36, 0.45, and 0.54). The average shear stress only showed a significant decrease when M/V > 0.36, as shown in Figure 22a. The plates with four shear stands had a higher average shear stress than the plates with two shear studs, implying that increasing the number of shear studs does improve the plate's performance. For a more complete comparison, a set of plates with two 12.5 mm diameter shear studs were added to the test using the finite element software. This shows that the green triangles are slightly higher than the gray squares (two-stud group) and the blue triangles are slightly higher than the red circles (four-stud group). S7 has a lower average shear stress than S2 because it breaks outside the shear reinforcement zone. This suggests that the diameter of the shear studs has only a minor impact on the plate's efficiency. However, the trend of the M/V versus average shear stress curves is similar for the four groups. The average shear stress is essentially constant when M/V is less than 0.36, and it decreases as M/V increases. In this experiment, the maximum M/V simulated was 0.54, with V representing the slab-column connection's self-weight. The specific values are summarized in Table 3. The naming rule for the newly added model is the number of studs--diameter of studs--ratio of M/V. The stresses in the critical section were not measured in this experiment, so the numerical simulation is a complement to the experiment in this respect. For the simulations of different M/V cases for the experimental samples of [PERSON] and [PERSON], the average shear stresses on the critical section of the eccentric side plate do not differ much (Figure 22b). The five groups have similar trends. As M/V increases from 0 to 0.5, the average shear stress increases sharply. After that, as M/V increases, the average shear stress tends to level off and has a slight decreasing trend. It can be seen that the arrangement and number of shear studs have no significant effect on the shear stress. However, for [PERSON] et al. 's experiment, the effect of increasing the number of studs on the plate is obvious. The reason for this may be because the number of studs set in [PERSON] and [PERSON]'s experiment is 4, 7, and 9, where the minimum number already meets the load-bearing requirement. When the joints are subjected to bending moments, too many studs may not contribute much to the effect. The simulated data are shown in Table 3; for experimental samples P1-P5, three different M/V cases were added to the model for each plate, with the naming rule of experimental sample name-studs' diameter-ratio of M/V. Figure 21: Control perimeter according to ACI-318.