2013-2023: ten years of experimental, numerical and measurement developments with the vertex multiaxial test bench

Abstract

The VERTEX test bench was designed to fulfil the need of virtual testing in the framework of certification of aeronautical structures. Funding obtained in 2013 for a total amount of 3000 k€ made it possible to both fund the test rig design and manufacturing (500 k€) and initiate research. The choice of the design of the machine and the size of the specimen is based on a first experience of Castanié et al. [Exp. Mech. 44:5 (2004) 461–472]. The specimens are said to be technological in the sense that they do not represent a particular part of an aircraft but a technology and/or make it possible to study a scientific or industrial problem. In the first version, the area of interest (200 x 200mm2) proved to be too small and difficulties in finding the force and moment fluxes locally applied were raised. As a result, the area of interest was quadrupled (400 x 400 mm2) in VERTEX and a specific test/calculation dialogue had to be developed. VERTEX provides a low-cost solution for testing at an intermediate scale, representative of larger scale tests, to provide rapid feedback on new technologies and/or materials. The machine is mainly made up of a tubular box on which the specimen is bolted to complete the upper face of the central part. Jacks 1 and 2 can be pushed or pulled symmetrically to bend the box, locally creating tension or compression on the sample. Jacks 3 and 4 can be pushed to twist the centre of the box, locally creating shear on the sample. An air-pressurised rubber bladder can be added in the central box to load the sample with pressure. The four jacks and the bladder pressure can be controlled independently to apply combined structural loadings in tension/compression + shear + pressure on the sample