  In this paper, an iterative method for real-time hybrid testing (RTHT) is
proposed. The method seeks to iteratively balance the interface conditions
between the physical and numerical substructures by controlling the periodic
demand of the actuators. It is then suitable for RTHT of structures undergoing
a periodic response, e.g. structures excited at resonance. We demonstrate the
capabilities of the method on a cantilever beam in bending motion with two
degrees of freedom at the interface, which we use as a prototype for future
testing of aircraft wings. We show that a number of challenges arise in these
settings, such as the difficulty in measuring interface forces while
controlling a continuous structure and the instability of the hybrid test for
small time delays. Classical RTHT strategies could produce inaccurate or
unstable outcomes, whereas the proposed method is able to attain very good
interface synchronisation in a wide range of tested scenarios.
