Introduction
Fabrication and Testing
Material and Printing Process
Design Parameters of Isogrid Structures
Rib width, mm | 3 | 3 | 3 | 3 | 5 | 5 | 5 | 5 |
---|---|---|---|---|---|---|---|---|
Rib thickness, mm | 4 | 8 | 10 | 15 | 3 | 8 | 10 | 15 |
Tensile Test
Buckling Test of Isogrid Structures
Scanning Electron Microscope Analysis
Results and Discussion
Tensile Test
Buckling Test of Isogrid Structures
Structure | Undried | Dried | Moisture loss, % Increase in specific resistance, % | |||
---|---|---|---|---|---|---|
Pmax, KN | Pmax/w, KN/g | Pmax, KN | Pmax/w, KN/g | |||
3x4 | 1.1 | 0.05 | 2.07 | 0.09 | 1.16 | 47% |
3x8 | 13.2 | 0.29 | 14.85 | 0.38 | 0.89 | 22% |
3x10 | 21.3 | 0.39 | 24.0 | 0.47 | 0.89 | 18% |
3x15 | 32.1 | 0.39 | 35.4 | 0.48 | 0.87 | 18% |
5x4 | 1.68 | 0.05 | 2.48 | 0.07 | 0.97 | 32% |
5x8 | 19.37 | 0.28 | 23.56 | 0.34 | 0.74 | 16% |
5x10 | 31.6 | 0.38 | 37 | 0.45 | 0.81 | 16% |
5x15 | 49.73 | 0.39 | 59.25 | 0.47 | 0.72 | 16% |
Scanning Electron Microscope Analysis
Conclusion
-
The load recorded during buckling test increases with displacement up to a peak value reached at to the onset of buckling; the dried configuration is characterized by a rise in the load applied to the isogrid structure during buckling test;
-
Isogrid structures can fail under local or global buckling, as a function of geometric parameters; the moisture content does not affect the failure mode;
-
Irrespective of the rib thickness and moisture content taken into account, the maximum specific buckling load, decreases with the rib width, even though such effect is negligible as the undried configuration is considered. As the rib thickness increases, the maximum buckling load linearly growths until the rib thickness of 10 mm is reached; then, as the rib thickness further increases up to 15 mm, the Pmax/w value remains constant.
-
The dried isogrid structures lead to an increase of both resistance and specific resistance;
-
Moisture can be easily removed from thin isogrid structures;
-
The more the moisture is removed, the more the increase in specific resistance is evident;
-
The dried isogrid structures fail in a brittle manner while the undried ones present a ductile fracture;
-
SEM images showed the differences on the fracture surfaces of dried and undried isogrids.