Smart materials and structures: VTT Research Program 2000-2002

This publication documents the presentations given at the closing seminar of the "Smart Materials and Structures" (ÄLYMARA) technology program. The publication also reports the main results of the four subprojects of the research program. The aim of the "Active materials" subproject was to gather information on available active materials and to provide support in materials issues for the other three subprojects. A state-of-the-art literature review including functional solid state, polymer and fluid materials was reported. The purpose of the "Precision motion and force" subproject was to develop know-how to apply functional materials in the production of controlled motion and forces. Several prototype structures were designed and implemented: SMA-actuator based "finger", SMA wire-based deforming "bridge", piezo actuator-based gripper including a PC-controller system (1 MSc thesis) and a novel SMA-wire actuator concept, for which a patent has been applied. The "Active durability control" subproject developed know-how to implement machines capable of autonomously controlling fatigue of structures. Several studies (1 MSc thesis) on active control, measurement and signal analysis techniques were reported. Functional virtual prototype with a fuzzy logic durability controller was set up and used to demonstrate the active concepts. In the "Active vibration control" project, a test and demonstration environment was built to study adaptive control systems in active vibration control of rotors. A LicSc thesis was prepared on the basis of the promising results. Semi-active vibration control of vehicle cabins using MR fluid-based dampers and skyhook and fuzzy logic control schemes were studied. Laboratory experiments and computer simulations were used to verify the potentiality of semi-active control.