Characterization of Kelvin Cell Cored Sandwich Structures with Analysis and Experiments

Abstract: In order to satisfy the mechanical requirements for space structures, achieving lightweight designs is of the greatest significance. The primary focus of this study is the utilization of Kelvin cell core in the design of sandwich structures for space applications. The research encompasses a variety of production techniques, analyzes, and tests related to the design of sandwich structures with Kelvin cells as the core material. While a variety of configurations are evaluated in a general sense, particular configurations are examined in greater extensive detail. In this context, the structure's bending stiffness, compression stiffness, and vibration characteristics are analyzed. The analytical procedure begins with a simplified structure analysis, followed by the modeling of the actual geometry. According to applicable standards, stiffness values are calculated based on the deflection results of the analyzes. However, it is important to note that the tests performed on the modeled structures are conducted in a laboratory environment using additively manufactured samples. This permits a comparison between the obtained test results and the findings of the analyzes, shedding light on the effect of the manufacturing method. This study demonstrates that the honeycomb sandwich structure is superior in terms of overall stiffness. In addition, a specially designed reinforced Kelvin Cell structure possesses exceptional bending rigidity properties. In light of these findings, it is clear that the combination of Kelvin Cell core and specific reinforcement strategies has the potential to improve the mechanical performance of sandwich structures. In addition, the deformation results revealed by the analyzes showed that the structure can be deformed in large amounts in directions other than the direction of the force it is exposed to. This situation is of great importance for damping in space applications. As a result of vibration analyzes and tests, the effect of stiffness and mass increase in a certain direction on natural frequencies has been revealed, and with 3-point bending tests, the facing elastic modulus and core shear modulus values of the structure have been determined separately and its effect on the sandwich structure has been shown. Accordingly, this study examined and evaluated many aspects of the possible role of the Kelvin Cell in space applications.