In this paper, an experimental and analytical study on the buckling and postbuckling control of a laminated composite beam with eccentrically embedded SMA wire actuators is performed. For the purpose of enhancing the critical buckling load, buckling control is investigated through the use of reactive moment associated with the shape recovery force of SMA wire actuators. The increased critical buckling load and alteredde flection shape due to the effects of activation of embedded SMA wire actuators are represented qualitatively and quantitatively on the load-deflection behaviour record considering the stacking sequence of the laminate, slenderness ratio of the beam and activation conditions of the SMA wire actuators. By maintaining the desired deflection shape with the proper reactive moment, buckling control can be extended to the postbuckling of the SMA-composite beam subjected to an external load. Based on the experimental analysis, the new formula for the buckling behaviour, which is confined to a small deflection prior to the postbuckling, of a laminated composite beam with embedded SMA wire actuators is suggested. Based on the results of buckling control, the thermal buckling and postbuckling behaviours of a composite beam with embedded SMA wire actuators are also investigated experimentally and analytically. For the purpose of enhancing the critical buckling temperature and reduction of the lateral deflection for the thermal buckling and postbuckling, the characteristics of thermal buckling are investigated through the use of the shape recovery force associated with SMA wire actuators. The results of thermal buckling tests using uniformly heated and clamped composite beam specimens with embedded SMA wire actuatorsare presented and discussed. The temperature-load-deflection behaviour records present quantitatively how the shape recovery force affects the thermal buckling behaviour. A cross tangential method is suggested to calculate the critical buckling temperature on the temperature-deflection plot. The experimental results show that the shape recovery force reduces the thermal expansion of the composite laminated beam, which results in an increment of the critical buckling temperature and reduction of the lateral deflection of postbuckling behaviours. The new formula is also proposed to describe the critical buckling temperature of the laminated composite beam with embedded SMA wire actuators.
Our results presented suggest that a composite structure embedded with SMA has a potential for aircraft and space structures which is subjected to mechanical loading and exposed to an elevated temperature which influences phase transformation of SMA wire actuators.
