<p>The research in the field of digital twins and the availability of advanced simulative tools are reshaping numerous branches of engineering, enabling advanced monitoring, control, interrogation, and optimization technologies that offer continuous real-time insights across the entire lifecycle of a system. Integration with augmented reality tools further enhances user communication, providing new modalities for interaction. The paper presents a complete methodology and an example to build an interactive digital twin of a flexible structure undergoing nonlinear large displacement that can be explored and interactively interrogated thanks to the integration with an augmented reality system. The digital twin communicates with its physical twin by means of sensors, and the augmented reality system projects the results coming from the digital shadow (stress, deformation and displacement maps) on the physical twin in real time. The user can also interactively investigate the effect of changes in both dimensions and topology of the structure by intuitive gestures. The core of the interactive digital twin is based on the definition of an efficient reduced-order model of the component able to manage the real-time changes of the geometry and boundary conditions, solving and updating the results of the nonlinear model such that they can be projected back to the user in real time. The proposed methodology represents an example on which more complex scenarios and applications can be built, exploiting the full potential of the integration between reduced-order models, digital twins and augmented reality.</p>