The morphing properties of a smart fiber metal laminate

Abstract

This article investigates the activation characteristics of a novel fiber-metal laminate (FML) based on a nickel-titanium (Ni-Ti) shape memory alloy. Initial attention focuses on manufacturing this smart FML in which a woven glass fiber reinforced epoxy material is sandwiched between two shape memory alloy (SMA) outer skins. Activation tests on cantilever beams using a hot air gun have shown that the FMLs exhibits a distinct actuation capability in which beam rotations of up to 118 were recorded. An examination of the edges of polished samples indicated that no damage was incurred by the FML during the activation process. The functionality of the FMLs was enhanced through the introduction of embedded electrical resistance wires located between the composite and metal plies. Here, the embedded electrical wires were heated by passing an electric current through them, thereby activating the SMA plies in a more effective and controllable manner. As before, significant beam tip rotations were recorded in the FMLs in a relatively short time period. Finally, polymer-based optical fiber (POF) and fiber-bragg grating (FBG) sensors were introduced into the FMLs in order to monitor their deflection during the activation process. The results of these tests showed that such sensing elements can be successfully employed to monitor the actuation response of these layered laminates.

Review of Progress in Shape Memory Epoxies and Their Composites

“…The development of the SMA-containing SMEP hybrids started with the investigations of laminated beams [178,208,209,210] followed by 2D (shell) [211,212] and 3D structures [213] and devices [178]. These works contributed to clarify open issues with respect of embedding, positioning, content, maximum straining, minimum bending radius, actuation capability-related properties, etc.…”

Plastic Optical Fibre Sensors for Structural Health Monitoring: A Review of Recent Progress

“…In the experiment, the POF sensor was able to detect a change in the damping ratio as small as 2.5%. In a later study [34], the POF sensor was applied to a nickel-titanium fibre metal laminate to monitor the morphing response of the hybrid laminate and the POF signal was found to agree well with collocated electrical strain gauges. Following activation of the smart fibre metal laminate (FML) by air through a heat gun, the shape memory alloy (SMA) layers deformed according to the shape it was trained (i.e., curved) and the POF sensor was found to faithfully monitor the flexural response of the smart composite.…”

Optical Sensors Based on Plastic Fibers

“…A recent area where POF sensors have been applied is in the development of smart structures. Cortes et al [ 85 ] presented a study in which either GOF-FBG and POF sensors were introduced into a glass fiber laminated composite structure and into a shape memory Ni-Ti alloy. The POF sensor was based on the measurement of the displacement of two cleaved fiber surfaces contained within the tube.…”