Intracranial aneurysm is a pathology related to the biomechanical deterioration of the arterial wall. As yet, there is no method capable of predicting rupture risk based on quantitative, in vivo mechanical data. This study is part of a large-scale project aimed at providing clinicians with a non-invasive, patient-specific decision support tool, based on the in vivo mechanical characterisation of the aneurysm wall. To this end, an original arterial wall deformation device was developed and tested on polymeric phantom arteries. Concurrently, a computational model coupled with the experimental study was developed to improve understanding of the interaction between the arterial wall deformation device and the aneurysm wall. An original procedure was implemented to validate the numerical model against experimental results. The deformation induced by the device on the polymeric phantom arteries is quantified by Digital Image Correlation. The Fluid-Structure Interaction between the device and the arterial wall was modelled numerically with the Finite Element method. The validation procedure encompasses the extraction and the interpolation of the numerical results. The computed strains were compared with the data measured experimentally. The numerical results interpolated on the experimental reference image were associated with several deformation device locations. These configurations induced strains and displacements ranges that included the experimental results, which validates the proposed model. The reliability of the procedure was validated with various study cases and artery materials. The procedure could be extended to experimental studies involving more complex phantom arteries in terms of shape and wall heterogeneity.