## 3 Results and Discussion  
The elastic properties of composite materials prepared with plain and twill-woven UHMWPE fibers were predicted using FEA, and the results are shown in Figure 3. Textile composites contain fabrics with their fibers arranged perpendicular to each other. Because these fibers are arranged at 90\({}^{\circ}\) and 0\({}^{\circ}\) angles to each other, forming interwoven textiles, E11 and E22 of the x- and y-axes of the composites exhibited the same results. In contrast, E33, which is the thickness direction of the composites, has a more distinct trend than E11 and E22. When the volume fraction of the UHMWPE fiber was 45%, Plain-E11 was estimated to be 9.2 GPa. The elastic modulus increased with increasing volume fraction, reaching 16.0 GPa at an UHMWPE fiber volume fraction of 75%. The Plain-E33 elastic modulus was estimated to be 7.7 GPa when the volume fraction of UHMWPE fiber was 45% and 15.4 GPa when the volume fraction was 75%. In contrast, the elastic modulus in the Twill-E11 direction was 8.6 GPa at 45% fiber volume fraction and 15.0 GPa at 75% fiber volume fraction. The elastic modulus in the Twill-E33 direction was 7.1 GPa at 45% fiber volume fraction and 14.8 GPa at 75% fiber volume fraction. The difference in elastic modulus between E11 and E33 with  
Figure 2: Textile compositions using the plain and twill weaving methods (**a**) Plain weave VF45, (**b**) Twill weave VF45, (**c**) Plain weave VF75, (**d**) Twill weave VF75. increasing fiber volume fraction was insignificant. Based on the findings of this study, the elastic modulus of the composites, including the textiles prepared by the plain weaving method, was demonstrated to be greater than that of the textile composites prepared by the twill weaving method. The elastic modulus is a value that represents the stiffness of a material and is defined as the stress-to-strain ratio. The elastic modulus may be calculated using the slope of the elastic section of the stress-strain curve obtained from tensile or shear experiments performed on material specimens. Notably, the elastic modulus can be used to calculate the response of a material to a load. For example, it is feasible to predict how much a steel wire will stretch under tension or how much a column will buckle under compression. Thus, when UHMWPE is woven into a plain weave and used for composite fabrication, the stress and strain under an axial load are minimal. However, this is not true in the case of tensile strength. Tensile strength is a force that reflects the strength of a material. It is calculated by dividing the largest load that a material can resist when pulled in the direction of its length by the cross-sectional area of the material. Thus, to precisely determine the tensile strength, tensile tests should be performed on plain and twill-woven UHMWPE/PP composites, and the maximum stress should be compared. Generally, it is concluded that tensile strength, abrasion resistance, stiffness, and pilling resistance are higher in plain-woven composites compared with twill-woven composites because these mechanical properties are enhanced by increasing the number of interlacements of the warp and weft yarns and decreasing the number of floats in the weave. However, tearing strength is higher in twill-woven composites because this property increases with an increasing number of floats in the weave and fewer interlacements [42]. Thus, plain-woven textiles are suitable for composites that require high flexibility. Fabrics are generally constructed by the alternating arrangements of fibers; thus, G\({}_{23}\) and G\({}_{31}\) of the x- and y-axes of the composites exhibited the same results. Figure 4 shows the predicted shear modulus behavior of the composites in relation to the UHMWPE fiber volume fraction based on FEA. The shear modulus of Plain-G\({}_{12}\) was estimated to be 1.8 GPa when the volume fraction of plain-woven UHMWPE was 45%, and it increased to 4.9 GPa when the UHMWPE volume fraction was 75%.