Characterisation of wire rope isolators under dynamic conditions: experimental-numerical analysis

This thesis aims to dynamically characterise the Wire Rope Isolators (WRIs), nonlinear devices used in civil and military applications for vibration isolation and shock protection, thanks to their ability to dissipate energy through hysteresis phenomena. However, accurately predicting their behaviour remains a challenge since often manufacturers provide only quasi-static stiffness curves, which do not account for real dynamic effects. This thesis proposes the introduction of correction factors to be applied on quasi-static curves to characterise the dynamic behaviour of WRIs and solve this problem. The study is structured with an initial experimental investigation to identify the main dynamic characteristics of the isolators, followed by numerical simulations that use ANSYS software to replicate their behaviour in real conditions. With the comparison between the experimental and numerical data, the correction factors are determined and then incorporated into the quasi-static curves. The refinement of the initial curves provided through these correction factors allows defining a model capable of returning an accurate representation of the actual response of the WRIs predicting their dynamic behaviour, improving the design and the optimisation of vibration isolation systems for industrial applications. The last part of the thesis demonstrates with validation simulations the effectiveness of the proposed methodology. This thesis also poses itself as a reference framework for future applications, contributing to a deeper understanding of the mechanisms governing the dynamic behaviour of WRIs.