## 5 Results
### Damage Patterns  
The damage visualizations in this section correlate to the time step at which the frame exhibits its highest seismic reaction, often linked to peak base shear or inter-story drift. The findings do not represent the conclusive stage of the investigation but rather the peak of structural demand, which most clearly demonstrates damage localization. An analysis of damage patterns in concrete has been conducted using the tension and compression damage variables established in the CDP model. This analysis reveals significant differences between frames employing traditional RC beam-column joints and those equipped with ACPH devices. In conventional frames lacking an artificial hinge, beam ends situated near the column faces tend to experience considerable tensile cracking, as evidenced by elevated tension damage values. Furthermore, compressive failure may arise at the upper or lower fibers of the beam if subjected to substantial inelastic rotations. Such cracking  
Figure 14: Plastic strain damage fields in the four frame configurations (1B1S, 2B1S, 1B2S, and 2B2S) with and without an ACPH. can sometimes extend into the edges of the column, resulting in a widespread damage zone that undermines the structural integrity of the joint. Conversely, the introduction of the ACPH subassembly results in the tension and compression damage distributions within the RC being largely contained to minor cracking areas that occur at mid-span or around the column base. This pattern of damage is notably less severe than that observed in traditional RC joints. The predominant inelastic demands are instead transferred to the steel hinge plates, which display distinct yielding as indicated by plastic strain contour plots, particularly in regions where the replaceable fuse element is intentionally designed to be weaker in bending. This concentration of steel deformation mitigates the risk of extensive cracking or crushing in the surrounding concrete, thereby safeguarding the stability of both the beam and column. Visual assessments of FEM compressive damage outputs have been illustrated in Figure 12.  
Upon examining the compression damage present within the frames,  
1. It was determined that all frames exhibited signs of compression damage at the base of the columns;
2. In the analysis of the beams within the one bay characterized as 1B1S and 1B2S frames, it is noted that the peak compressive damage limit recorded in the RC frame adjacent to the column face reached a value of 0.87. However, in the ACPH frame, compressive damage near the column face in the beam is minimal, approaching zero. Furthermore, it was observed that the middle beam, situated between the ACPH frames, exhibited no signs of compressive damage. This pattern remains consistent across both single-story and double-story frames, indicating that an increase in the number of stories does not significantly affect the level of compressive damage observed;
3. An analytical examination of the beams within the 2B1S and 2B2S frame configurations reveals that the highest extent of compressive damage, as delineated in the reinforced concrete (RC) frame, near the exterior columns and adjacent to the middle column's face, reached a value of 0.87. Furthermore, compressive damage was additionally identified in the beam-column joint area associated with the middle column. When analyzing the ACPH frame, the extent of compressive damage near the column face and within the joint area of the middle column is observed to be approximately 0, with no compressive damage recorded in the middle beam situated between the ACPHs. These findings are consistent across both two-story and one-story frames; the increment in story count did not significantly affect the compressive damage levels, given that the damage recorded at the first story was sufficiently low. The tensile damage outputs produced by the finite element method (FEM) have been represented visually in Figure 13. An analysis of the tensile damage observed within the frames reveals important insights. 1.