NASA Marshall Space Flight Center’s Fluid Structure Coupling (FSC) technology is a highly efficient and passive method to control the way fluids and structures communicate and dictate the behavior of a system. This technology has the demonstrated potential to mitigate a multitude of different types of vibration issues, and can be applied anywhere internal or external fluids interact with physical structures. For example, in a multistory building, water from a rooftop tank or swimming pool could be used to mitigate seismic or wind-induced vibration by simply adding an FSC device that controls the way the building engages the water.
FSC is a passive technology that can operate in different modes to control vibration.
- Harmonic absorber mode: The fluid can be leveraged to act like a classic harmonic absorber to control low-frequency vibrations. This mode leverages already existing system mass to decouple a structural resonance from a discrete frequency-forcing function, or provide a highly damped dead zone for responses across a frequency range.
- Shell mode: The FSC device can couple itself into the shell mode and act as an additional spring in series, making the entire system appear dynamically softer and reducing the frequency of the shell mode. This ability to control the mode without having to make changes to the primary structure enables the primary structure to retain its load-carrying capability.
- Tuned mass damper mode: A small modification to a geometric feature allows the device to act like an optimized, classic tuned mass damper, enabling the primary structure to take on the damping characteristics of the FSC device.
FSC devices minimize size and weight because they can leverage existing fluids in and around the system. They are inexpensive, easy to retrofit to existing fluid systems, less complex because control is achieved with a single fluid source, and highly efficient because they achieve complete control of the phase lag between fluid and structure. The FSC technology can be used in structural applications for multistory buildings, stacks, towers, bridges, and pools for spent nuclear fuel; in offshore oil rigs and above-ground storage tanks; in municipal water tanks/towers; and in marine applications for multidirectional stabilization of vessels or platforms.