## 3 Results and Discussion  
### Experimental Strain Measurement  
Local strain measurements were conducted across four textile structures under varying applied strain levels, determined by reducing the pattern size of the waistband using the Velcro method. The Velcro strips, attached to the fabric's edges, allowed for controlled reductions in the waistband size by overlapping the strips, simulating strain levels of 5%, 10%, 15%, and 20% without distorting the material. Figure 3 illustrates the strain behavior of the four fabric structures--SJ, INT, SJP, and INTP--under controlled strain levels of 5%, 10%, 15%, and 20%. When the fabric was stretched, the local axial strain increased consistently, reflecting the inherent stretchability of knit fabrics. Even at an initial 5% applied strain, the local axial strain exceeded 15% in all fabric samples. As the strain increased to 20%, the local axial strain expanded to values between 25% and 40%, varying based on the knit structure--single jersey (SJ), interlock (INT), and elastane yarn inclusion through the plaiting technique (single jersey-plaited (SJP), interlock-plaited (INTP)). The results show that the SJ fabric exhibited the highest local axial strain, with values increasing up to 40% at 20% applied strain. In contrast, the interlock (INT) fabrics displayed more controlled strain behavior, likely due to the increased structural stability inherent in the INT fabric. The incorporation of elastane yarn in the plaited structures (SJP, INTP) had a moderating effect on the strain behavior. Figure 3c,d show that the local axial strain was lower for both the SJP and INTP fabrics, indicating that the elastane reduced the degree of stretchability. It should be noted that, in Figure 3b,d, the data points are limited due to material constraints. Due to the inherent stiffness of these materials, they were unable to stretch beyond 10% on the mannequin without risking damage to the fabric's integrity. This limitation resulted in fewer data points and reflected the material's inherent properties, emphasizing its rigidity under strain. Building on the understanding of the experimental local strain test results, the simulation test outcomes are presented as dotted lines in the same Figure 3. Both the SJ and SIP fabrics demonstrated relatively accurate predictions of the local strain, as represented by the simulation model (Figure 3a,b). The INT fabric also showed good alignment between the experimental and simulated strain up to an applied strain of 15%. However, at an applied strain of 20%, although the experimentally observed local strain in the axial direction for INT was 28.67% (\(\pm\)3.77%), the corresponding simulation value was significantly higher at 38.93% (\(\pm\)1.95%) (Figure 3c). A similar overestimation was observed for the INTP fabric, as shown in Figure 3d, indicating potential limitations in the simulation model's ability to accurately capture the nonlinear mechanical behavior of double-knit textile structures under higher levels of applied strain (beyond 15%) [6]. Moreover, the observed differences \begin{table}
\begin{tabular}{c c c} \hline \hline
**Method** & **Equipment Used** & **Details** & **Setup Image** \\ \hline B-1. CLO3D® Pressure Simulation (CLO Virtual Fashion, South Korea) & Built-in function in CLO3D (v. 7.3) that simulates pressure. & \\ B. Simulated pressure & Uses CLO3D’s built-in strain measurements and digitized stretch stiffness to predict pressure via [PERSON]’s model [6; 13]. & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: _Cont._in the transverse and bias strain behaviors have important implications for fabrics' performance in applications requiring controlled deformation, such as compression garments. The greater structural stability of the INT fabric, as evidenced by its lower transverse strain values, suggests that it may offer better consistency in maintaining compression over time compared to the SJ fabric.