## 2 Materials and Methods  
FDM parameters and their effects on the strength and surface texture have been examined in previous research [49; 50; 51]. In this case, infill pattern and density were the main goals showing how they influence dimensional accuracy, material usage, and mechanical properties. A broad range of patterns such as grid, honeycomb, wiggle, zigzag, and other shapes have been generated and produced by FDM printers, but not many research works have investigated designing patterns using the CAD process. Therefore, in this work, SR analysis and tensile strength were performed to analyze the effects of these two pattern batches in dog-bone samples. This sample was designed by following ISO/ ASTM D638, the standard test method for tensile properties of plastics. As shown in Figure 2, the base structure was designed in CATIA V5(Dassault Systemes, Velizy-Villacoublay, France), and regarded as tensile strength standards Type 1. Figure 2: Drawing of a dog-bone shape sample. Concentric, grid, triangle, and zigzag patterns were chosen and designed as shown in Figure 3. A solid sample was also designed for the FDM process that slicer software followed the same pattern and density as the CAD procedure. Infill density was also another factor that was required to be analyzed. Therefore, each pattern was 3D printed with the same and different densities to investigate their effects for both groups (see Table 1). Based on the previous research by [PERSON] and [PERSON] [45], the line width was set to 0.5 mm instead of 0.4 mm to avoid erroneous openings in the printed lines. The shell thickness was 0.8 mm for all samples. In the design procedure, patterns must be designed properly to avoid gaps and poor layer adhesion. Due to the high capability of FEA, it is possible to examine parts' behavior under compression or tensile tests [52]. Infill patterns indicate specific behavior in printed samples under different loads. Hence, analyzing samples is vital for finding the layer's reaction under tensile load. CAD samples were examined via Abaqus(r) (2020 version, Dassault Systemes, Velizy-Villacoublay, France) due to the existence of infill patterns before the printing process. The designed samples were converted to initial graphics specification \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Process** & **Infill Pattern** & **Infill Density (\%)** & **Process** & **Infill Pattern** & **Infill Density (\%)** \\ \hline \multirow{4}{*}{CAD} & \multirow{4}{*}{Concentric} & 20 & \multirow{4}{*}{\
\begin{tabular}{c} Concentric \\ 30 \\ \end{tabular} } & 20 & \multirow{4}{*}{
\begin{tabular}{c} Concentric \\ 30 \\ \end{tabular} } \\  & & 30 & & \\ \cline{1-1} \cline{2-5}  & Grid & 60 & \multirow{2}{*}{FDM} & \multirow{2}{*}{Grid} & 30 \\ \cline{1-1} \cline{2-5}  & Triangle & 10 & & & 10 \\ \cline{1-1} \cline{2-5}  & Zigzag & 30 & & Zigzag & 30 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Infill density in CAD and FDM. Figure 3: 2D/3D design of (**a**) concentric, (**b**) grid, (**c**) triangle and (**d**) zigzag patterns of sliced dog-bone samples. (IGS) format in CATIA V5. Failures and von Mises in the simulation process were obtained. The method elaborated to find out the differences between printed and simulated CAD specimens. Static analysis, millimeter (mm) unit, and PLA material properties were assigned in the simulation procedure. The type of mesh used in this process was quadratic tetrahedral elements of type C3D10. Features of each simulated CAD sample are provided in Table 2.  
Ultimaker 3 Extended machine (Ultimaker, Geldermalsen, Netherlands) with two extruders was used to print all specimens. The biodegradable green PolyLiteTM PLA material (Polymaker, Shanghai, China) with a 1.75 mm filament diameter was chosen due to its reliable properties, good strength, and stiffness (see Table 3) [53].