Carbon Fiber Reinforced Smart Laminates with Embedded SMA Actuators-Part I: Embedding Techniques and Interface Analysis

Up to now one of the main limits for a large use of shape memory alloys (SMA)-based smart composite structures in the aerospace industry is the lack of useful numerical tools for design. Moreover, technological aspects still need a more detailed investigation. This paper shows how to overcome issues regarding embedding of NiTiNOL wires in carbon fibre/epoxy laminates. A crucial aspect of those structures is related to the load transfer capabilities between the SMA actuators and the host material during their activation. Embedding techniques developed for taking into account problems like thermal and electrical compatibility between actuators and host material and passive/active invasivity are reported in this paper. Simple smart laminates with several actuators were manufactured, tested, and deeply analyzed. In order to characterize the interface in the real operative conditions, pull-out tests were conducted on NiTiNOL wires embedded in composite fiber laminates. The results were compared to standard experiments on wires embedded in pure epoxy resin blocks.