## 3 Results
### Mechanical Testing
When the individual pore layer was loaded, the compressive force increased, and conversely, when the layer was deformed, the compressive force decreased. This process was repeated until a 60% deformation was reached. All samples in a testing group of sample 3 had the same course of deformation. Under load, the area of plastic deformation occurred at a load value of 8.9 kN. The resulting stresses at this load value 251 MPa. The value of the maximum stress induced in the samples is 302 MPa at a maximum force of 11 kN. The difference between the yield strength and the stress limit is about 50 MPa. All samples started crushing at about 7% of the relative compression. From the diagram in Figure 11c, it is possible to see the loading and unloading of individual crushed pore layers. Figure 10: The resulting deformations of samples after pressure testing: (**a**) bending, (**b**) fracturing, (**c**) crushing. During the pressure testing of sample 4, not all manufactured pieces were evaluated because of the high strength of this type of specimen and due the machine limitation. The two specimens did not withstand the load and their deformation occurred due to a fracture caused by shear forces. For other samples, no external fracture has occurred. The whole course of deformation was similar to the samples of type 1. Fracture of the samples occurred at approximately 32% of relative compression. The area of plastic deformation occurred at a load value of 77 kN at a stress value of 1170 MPa. The average maximum stress that arose in the samples was 1618 MPa, which is the highest value of the maximum stress. The maximum loading force used was up to 120 kN. There is a difference of approximately 450 MPa between the onset of plastic deformation and fracture. The approximate modulus of elasticity ranged from 10 GPa to 11 GPa. The area of plastic deformation has a linear course (Figure 11d). The end of testing occurred at the breaking of the samples. Disruption and fracture of sample type 5 occurred due to shear forces. In the first phase of deformation, the specimens began to deviate from the longitudinal axis, and in the second phase, fracture occurred. Unlike other samples that were deformed in this way, the top and bottom of the sample remained inseparable. There was no crushing of the material observed. In this type of sample, the specimens began to plastically deform at a loading force of approximately 31 kN, creating a stress of approximately 525 MPa in the specimens. The maximum stress at which the samples were mechanically disrupted was 1160 MPa at a maximum force of 82 kN. The average value of the modulus of elasticity in these samples was 8.6 GPa. The average value at which a fracture occurred is 30% of the relative compression. From the beginning of the plastic deformation to the fracture value, the difference is 635 MPa. It can be seen from the diagram in Figure 11e that after reaching the maximum stress, the samples began to break. In the first phase of the fracture, the sample was relieved and subsequently loaded. This was because the crushing of one layer of pores occurred at first, and subsequently, the sample was sheared. Figure 11: Pressure testing diagram of (**a**) sample 1, (**b**) sample 2, (**c**) sample 3, (**d**) sample 4, (**e**) sample 5, (**f**) sample 6. During the pressure testing of the type 6 sample, the test specimens were disrupted due to shear forces. The resulting failure of the structure resembles a crack, which did not cause the separation of the upper and lower parts of the specimens. The sample fracture occurred at approximately 28% of the relative compression. The area of plastic deformation occurred at a stress value of 198 MPa on average, which arose under a force of 3.5 kN. The maximum stress that arose when loading the sample is on average 1033 MPa at a maximum force of 45 kN. To break specimens, the stress value had to be increased from the yield point by 835 MPa. The value of the modulus of elasticity is on average 5 GPa.