Abstract
The interest to use steel foam sandwich structures is expanding in various industrial applications, and more attention is paid to improve the properties of these materials. However, liquid and solid intrusions can severely hamper their useful characteristics. This study aims to provide an experimental investigation on the potential of steel foam (hollow sphere) sandwich specimens to operate as passive dampers in flexural vibration and to preserve their capabilities when affected by the intrusion of external particles. The authors utilized two different experimental examinations, random noise (white noise) and impact (hammer) tests. The specimens consist of a hollow sphere foam core sandwiched between two mild steel sheets, bonded with a thermosetting epoxy resin. To simulate the intrusions of granular materials in operating conditions, the metallic foam cores of the samples were partially filled with different percentages of quartz sand particles. The two-phase specimens were then compared to the pristine (single-phase) ones. The resulting estimates of the vibrational damping ratio for single and double-phase metallic foam specimens were used to calibrate the respective Finite Element models, which proved to be suitable for replicating the damping characteristics of the specimens.
Highlights
In the last few years, the growing demand to detect new structures with better mechanical properties and lower weight gave the direction to improve and employ novel foam sandwich elements [1]
The main aim was to determine their performance as passive dampers due to vibrations when disturbed by sand intrusions in their core
The damping ratio for the 1st natural frequency of the single-phase specimen is 1.55 % and 1.73 % sequentially, besides, for the two-phase sandwich core, the average damping ratio increased to 2.10 % and 1.17 %
Summary
In the last few years, the growing demand to detect new structures with better mechanical properties and lower weight gave the direction to improve and employ novel foam sandwich elements [1]. These can be made by diverse materials mixtures. Metallic foams are made up of two thin sheets (skins) enclosing a central core to which they can be linked with different methods, e.g., bonded together [2, 3], to support the load and pressure between its components [4]. High stiffness, damping capability, vibration frequency (e.g., B787).
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