Correlating interfacial properties with stress transfer in SMA composites

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

OSTI ID:175111

Kline, G E; Jonnalagadda, K; Sottos, N R ^[1]

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1. Univ. of Illinois, Urbana-Champaign, Urbana, IL (United States)

Shape memory alloy (SMA) wires have been proposed as large strain actuators for use in smart structures. SMA wires can be embedded in a host material to alter the stiffness or modal response and provide vibration control. The interaction between the embedded SMA and the host material is critical to applications requiring transfer of loads or strain from the wire to the host. Paine, Jones and Rogers have asserted the importance of interfacial adhesion between embedded SMA wires and the host material. When the SMA wires are actuated, large shear strains are generated at the SMA/host interface. The stronger the interface, the greater the transfer of strain from the actuator to the host material. Although there has been a significant amount of research dedicated to characterizing and modeling the response of SMA alone, little work has been done to understand the behavior of embedded SMA wires. Maximum displacement, load transfer and repeatability of actuation of the embedded wire are particularly critical in assessing the effects of the host material. This work continues to investigate the interaction between SMA wires and a host polymer matrix. High resolution photoelasticity was utilized to study the internal stresses induced during actuation of an embedded shape memory alloy wire in a polymer matrix. The influence of several wire surface treatments on the resulting stresses and load transfer was investigated. Four different surface treatments were considered: untreated, acid etched, hand sanded and sandblasted. Pull-out data indicated that sandblasting of wires increased the SMA/polymer interfacial bond strength while hand sanding and acid cleaning actually decreased the bond strength. Wires with greater adhesion (sandblasted) resulted in higher stresses induced in the polymer while those with lower adhesion transferred less load. Overall, properties of the SMA/polymer interface were shown to significantly affect the performance of the embedded SMA actuator.

• OSTI ID: 175111
• Report Number(s): CONF-950686--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ACTUATORS
ADHESION
ALLOYS
INTERFACES
MICROSTRUCTURE
PERFORMANCE
PHOTOELASTICITY
POLYMERS
SHAPE MEMORY EFFECT
SHEAR
STRAINS
STRESSES
SURFACE TREATMENTS
WIRES