## 3 Results  
### Initial Material Characterization  
Concerning experimental testing of lattice structures according to the proposed design model, the first step was investigating prime material characterization to obtain results synchronized and adjusted with the lab environment and conditions. Prime material mechanical characterization was conducted at the 1 mm/min displacement rate. Tensile tests were run until the specimens were fractured. The applied load and stress-strain values were measured in quasi-static conditions, and tensile tests were performed on five specimens in a series according to ISO 527-2. Then, the stress-strain curves were plotted for all five specimens using Shimadsu's TrapeziumX software and MS Excel (Microsoft Office 365 (Version 2406 (Build 17726.20126))) (Figure 9). The characterization delivered vital material properties parameters loaded from the stress-strain curve, such as Young's modulus, deformation, yield stress (S\({}_{y}\)), maximum or ultimate tensile stress (S\({}_{\text{max}}\)), and tangent modulus (E\({}_{t}\)). These parameters determined the numerical model in the later heading section. Yield strength is the most significant point indicating tensile stress value in determining prime material parameters for the numerical model creation. It also represents the boundary point after which the curve's flow stress increases linearly but flees the elasticity area. Since the prime material examination is ASA FDM thermoplastic, there is no clearly emphasized distinction in position on the stress-strain curve between points of the yield and maximum tensile stress. Therefore, the assumption was that these two points coincide as predicted following the specified ISO standard [35]. According to testing results in Figure 7, and considering the mentioned assumption, five specimens delivered five maximum tensile stress values and derived an average maximum or yield tensile stress of 32.87 MPa, matching the manufacturer's material data  
Figure 9: Testing results in a series of five specimens for getting ASA engineering Stress-Strain response align with ISO 527-2.  
sheet [28] stated in Section 2.1. After this point, the diagram (Figure 9) showed a decreasing curve trajectory, confirming that the material reached the peak as its maximum response for set conditions, so it will be further donated and used as the maximum stress. All specimens experienced a peak tensile stress at an average of 3.7% strain, comparing again the manufacturer's material data sheet [28], and all had uniform characteristics of elongation in yield point, followed by a slight decline in the curve's flow stress for the ASA specimens. Elongation in breakpoint (E\({}_{\text{b}}\)) did not achieve uniform results. There are a few reasons for that: room temperature and humidity as well were not automatically controlled (the elongation at break increases with an increase in temperature), tested thermoplastic polymer is not characterized by significant ductile features, and ever-present additively manufactured imperfections inside specimens internal structure. Although elongation at break results seem scattered and nonuniform, the variation is expected when considering previously described reasons. Given the mentioned reasons, TrapeziumX software does the \"strain calculation at entire areas\", considering the whole stress-strain curve's testing plateau, particularly individual tensile peaks along the distance between E\({}_{\text{y}}\) and E\({}_{\text{b}}\) points, emphasizing these values as crucial in the prime material characterization (Figure 9). The tangent modulus is the third most significant material parameter crucial in creating a numerical analysis of lattice structures to compare results. The behavior of the thermoplastic polymer that is stressed beyond the elastic region must be described in the multilinear isotropic strain hardening material model setup. Strain hardening is evident through the tangent modulus, as it reflects the slope of the stress-strain curve.