Abstract:

Sandwich materials that are considered to have lightweight, well-flexural behavior, in addition to relatively high structural damping are considered significant by aerospace sectors due to the usage of such materials in specific aircraft applications including helicopter interior parts where vibrations and noises of high levels take place. The primary purpose of the research is to concentrate on sandwich structures with high damping values and appropriate flexural rigidity. The following conclusions were derived from the experimental and numerical data: • The specimens with holes have lower natural frequencies compared to normal specimens. Further increasing the hole diameter will further decrease the natural frequencies relatively. The lowest decrement at 50 percent hole diameter occurred for the maximum displacement condition. The highest decrements were observed for the case of nodal positions for both specimens. • It was observed that the velocity amplitude increased as the specimen with 15.5 mm thickness was subjected to holes compared to the normal specimen. This also occurred in the specimen with 54.6 mm thickness and the increment was higher than in the specimen with 15.5 mm thickness. • As the diameter of holes increases, an increase in the Irms values for both specimens takes place. The only intensity value that decreased is the one regarding 3rd natural frequency for the nodal position case. For specimen one, the highest increase in intensity value took place for nodal and maximum displacement positions. The highest intensity value increase occurred in the maximum displacement and then the nodal position case regarding the specimen with 54.6 mm thickness.