Experimental investigation of beams under coupled bending and torsion

The design of doubly-curved systems called for innovative modelling techniques to evaluate the final geometry of the structure. They can simulate the behaviour of beams under large displacements. Even though it is never analysed, the deformation path is can be critical in such complex configurations. This paper analyses the potential of digital technologies to investigate the behaviour of beams under bending-torsion coupling in large deformation. In a first part, we will present the setup for an experiment, based on the use of robotic arms. The versatility of robotic arms allows to access complex configurations or loading paths, while controlling the test either in displacements or in forces. In a second part, an enhanced photogrammetry procedure is introduced. The aim is to retrieve the geometry of the beam even in the case of complex 3D shapes. The acquisition yields a point cloud representation of the beam. Finally, we propose a workflow to make the interaction with robotic arm, simple and efficient. The novel experimental setup aims at making possible the study of beams with complex form, under ever more complex force.