Abstract-This paper reports on the fabrication of microactuators through wafer-level integration of prestrained shape memory alloy wires to silicon structures. In contrast to previous work, the wires are strained under pure tension, and the cold-state reset is provided by single-crystalline silicon cantilevers. The fabrication is based on standard microelectromechanical systems manufacturing technologies, and it enables an actuation scheme featuring high work densities. A mathematical model is discussed, which provides a useful approximation for practical designs and allows analyzing the actuators performance. Prototypes have been tested, and the influence of constructive variations on the actuator behavior is theoretically and experimentally evaluated. The test results are in close agreement with the calculated values, and they show that the actuators feature displacements that are among the highest reported.[ 2009-0259]Index Terms-Actuator, adhesive bonding, bias spring, cantilever, microelectromechanical systems (MEMS), NiTi, reset mechanism, shape memory alloy (SMA), silicon structure, SU-8, TiNi, wafer-level integration.

This paper reports on the wafer-level fixation and electrical connection of pre-strained SMA wires on silicon MEMS using electroplating, providing high bond strength and electrical connections in one processing step.The integration method is based on standard micromachining techniques, and it potentially allows mass production of microactuators having high work density.SEM observation showed an intimate interconnection between the SMA wire and the silicon substrate, and destructive testing performed with a shear tester showed a bond strength exceeding 1 N.The first Joule-heated SMA wire actuators on silicon were fabricated and their performance evaluated. Measurements on a 4.5 x 1.8 mm 2 footprint device show a 460 µm stroke at low power consumption (70 mW).

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A low-power high-flow shape memory alloy wire gas microvalve. Micromechanics and Microengineering,22( Journal of AbstractIn this paper the use of shape memory alloy (SMA) wire actuators for high gas flow control is investigated. A theoretical model for effective gas flow control is presented and gate microvalve prototypes are fabricated. The SMA wire actuator demonstrates the robust flow control of more than 1600 sccm at a pressure drop of 200 kPa. The valve can be successfully switched at over 10 Hz and at an actuation power of 90 mW. Compared to the current state-of-the-art high-flow microvalves, the proposed solution benefits from a low-voltage actuator with low overall power consumption. This paper demonstrate that SMA wire actuators are well suited for high-pressurehigh-flow applications.

A hybrid numerical-experimental methodology for the dynamic characterization of automotive rubber connections is presented. In order to predict the dynamic response of automotive structures, a finite element (FE) modelling approach is often used. A critical factor in the achievement of accurate dynamic or static predictions is modelling of non-linear connections between closures and car body. An experimental method is proposed for characterizing the dynamic behaviour of automotive weather strips. By means of a dedicated test bed, a frequency-dependent model of complex stiffness is identified for both normal and tangential loading conditions. The stiffness variability with quasi-static deformation amplitude and deformed shape is also investigated. The experimental data are then used to identify a linear FE model of vehicle rubber connections within the range 0-300 Hz. A simplified car door model and frequency response function (FRF) correlations are used to obtain an experimental validation of the proposed modelling approach.