In the field of compliant mechanisms, neutrally stable mechanisms are gaining interest for among others increasing actuation efficiency, vibration isolation and their use in metamaterials. Prestressing these mechanisms is necessary to provide the potential energy they require to reach their state of neutral stability. Current prestressing methods are limited by their need for individual application or relatively long activation times and limited reversibility, limiting mechanisms which utilize a multitude of neutrally stable flexures. This research aims to design a neutrally stable, enclosed volume joint on which prestressing utilizing a negative internal pressure is tested. The joint is first characterized together with a parameter study, used to understand the influence of its geometry, and a finite element model, to assess its predictive accuracy. An experimental setup is constructed, which measures the torque-angle behavior of the joint under different prestress conditions. The results are compared to the expected behavior, which is closely resembled for some of the prototypes, while the simulations prove to be only indicative of the general trend.

Acoustic-structural interactions present significant engineering challenges, particularly in the domains of noise reduction and vibration control. At ASML, measurement-based analyses have revealed that acoustic disturbance paths often dominate the dynamic behavior of atmospheric lithography machines. This project focuses on enhancing ASML’s current one-way coupled acoustic-structural modelling approach by developing a two-way coupled, known as vibro-acoustic, modelling framework. However, this advancement introduces substantial computational complexity, necessitating effective model reduction techniques. The primary objective of this work is to reduce vibro-acoustic models in a way that preserves their ability to be modularly coupled with other system components. To this end, three Component Mode Synthesis (CMS)-based reduction methods were evaluated, with only one proving suitable for both academic and industry-scale models. The resulting reduced-order models successfully retained the dynamic fidelity of the full system and enabled efficient coupling with other substructures. When applied to harmonic excitation analyses, the reduced models achieved a dramatic reduction in computational time, from several hours to approximately one minute, while accounting for the cost of model reduction.