## 3 Results and Discussion
### Analysis of the SolidWorks Simulation Results  
The deformation of the scaffold under tension or pressure is measured by the results obtained from the Solidworks simulation, as shown in Figure 8a,b. It can be seen that the maximum deformation of the scaffold is the maximum displacement of the scaffold surface.  
Figure 8c shows the simulation results on the performance of the scaffold with different porosity of the concave hexagon filled scaffold: the maximum displacement and force of  
Figure 8: Simulation results for the scaffold of different filled structures: deformation in the direction perpendicular to the upper surface (**a**) or parallel to the upper surface (**b**), stress-strain curves for different pores (**c**), and elastic modulus versus porosity in both directions (**d**,**e**).  
Figure 7: Tensile properties of different materials.  
the relationship between different porosity is shown in the curve, which shows that the higher the porosity, the greater the maximum displacement of the scaffold with the same filled pattern and the same force, indicating that the mechanical properties of the scaffold are worse. In a direction vertical to the upper surface, the elastic modulus of the scaffold with 53.26% porosity is about 1.29 MPa. When the porosity is about 70.26%, the elastic modulus is reduced to about 0.57 MPa, about 56% lower.  
As shown in Figure 8d,e, the elastic modulus can be regarded as an index to measure the difficulty of producing elastic deformation of the material. It is defined that the larger the elastic modulus was related to the greater stress that material undergoes a certain elastic deformation. For example, the larger value indicates the greater material stiffness; on the contrary, the smaller value indicates the better tensile property of the material. Therefore, it can be used as an indicator to evaluate the mechanical properties of the scaffolds, comparing the effects of different parameters and different filled patterns on the mechanical properties.  
From Figure 8d,e, we can conclude that in the direction perpendicular to the upper surface, the concave hexagon filled pattern is at a higher position curve, while the triangular and orthogonal filled patterns are at a lower level. This means that in this direction, the scaffold printed with the concave hexagon filled pattern has a significantly higher modulus of elasticity and better vertical stiffness than the scaffold printed with the orthogonal and triangular filled patterns, which is suitable for some scaffolds that require a little stiffness in the longitudinal direction. With 60% porosity, the concave hexagon algorithm prints scaffolds with an elastic modulus of 1.04 MPa, while the modulus are respectively 0.72 MPa and 0.81 MPa when triangular algorithms and orthogonal algorithm are adopted, and in the direction parallel to the upper surface of the scaffold, the concave hexagon filled pattern is at the lowest point of the curve and there is no significant difference in the curves of the orthogonal and triangular filled patterns. It means that when the three filled patterns print scaffolds with the same porosity, the concave hexagon scaffold has the lowest modulus of elasticity and has better elasticity to cope with issues that need lateral directional deformation such as trachea or skin, so the concave hexagon filled pattern can print scaffolds with more anisotropic features.