Investigation of mechanical properties of composite balsa structures

In this study, the mechanical properties of the bio-core sandwich composite structures produced in different configurations were investigated experimentally and numerically. Balsa woods of 4, 6, 8 and 10 mm thickness are used in the core element. Glass fiber / epoxy composites with 8 and 12 layers were used in [0], [0/90º] and [± 45º] fiber orientation slices on the top and bottom surfaces of the sandwich structure. The effects of the increase in the number of layers and core thickness together with the outer surface fiber orientation change of the sandwich structures produced by vacuum infusion method on the bending, impact and compression strength were investigated. For this purpose, three point bending, low velocity impact and edge compression tests were applied to the sandwich samples. The maximum damage load, surface stress and core shear stress values were determined as a result of the three point bending test performed in accordance with the ASTM C393 standard. Experimental and numerical data were compared with the finite element model created in the ANSYS program. In the low velocity impact test, tests with energy values of 15, 30, 45 and 60 J were carried out. Depending on the increase in impact energy, the values of maximum contact force, displacement and absorbed energy were examined comparatively. Edge compression tests were carried out in accordance with ASTM C364 standard. Variations of the obtained maximum damage load and compression stress according to the determined sandwich parameters were examined. Damaged samples were imaged in all three tests, Damage types in balsa wood and composite element were determined.