Flexible rods with embedded two-way shape memory alloy fibers

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:175110

Blonk, B.J. de; Bo, Z; Lagoudas, D C ^[1]

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1. Texas A&M Univ., College Station, TX (United States)

Shape Memory Alloy (SMA) wires are trained to exhibit the two-way shape memory effect and are embedded off the center axis of cylindrical rubber rods. Each rod contains two wires which are located above and below the rod centerline so as to cause deflection of the rod in the vertical plane upon actuation of the wires by electrical resistance heating. Two-way training of an SMA wire causes a hysteretic strain-temperature response at zero stress. A trained wire thus provides the advantage of returning to its original length when cooled back to the martensitic phase. Experimental measurements of the trained SMA wires produce the constants for the modelling of the two-way actuator, including the martensite and austenite transition temperatures as a function of stress. The mechanical response of the rods is calculated using a linearized rod theory, which is shown to be a reasonable approximation of the nonlinear rod theory for small SMA actuation strains. The constitutive behavior of the SMA actuator wires is calculated by using a unified model for cyclic loading of SMA material, which is reduced for trained SMA wires, and the specific hardening behavior is described by the cosine rule proposed by Liang and Rogers. The results of the modelling are correlated with the deflection and temperature results obtained experimentally.

• OSTI ID: 175110
• Report Number(s): CONF-950686--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ACTUATORS
ALLOYS
AUSTENITE
FIBERS
MARTENSITE
MATHEMATICAL MODELS
MECHANICAL PROPERTIES
PHASE TRANSFORMATIONS
RESISTANCE HEATING
RUBBERS
SHAPE MEMORY EFFECT
STRAINS
WIRES