Multiscale contact mechanics model for RF–MEMS switches with quantified uncertainties

Abstract

We introduce a multiscale model for contact mechanics between rough surfaces and apply it to characterize the force-displacement relationship for a metal-dielectric contact relevant for radio frequency micro-electromechanicl system (MEMS) switches. We propose a mesoscale model to describe the history-dependent force-displacement relationships in terms of the surface roughness, the long-range attractive interaction between the two surfaces, and the repulsive interaction between contacting asperities (including elastic and plastic deformation). The inputs to this model are the experimentally determined surface topography and the Hamaker constant as well as the mechanical response of individual asperities obtained from density functional theory calculations and large-scale molecular dynamics simulations. The model captures non-trivial processes including the hysteresis during loading and unloading due to plastic deformation, yet it is computationally efficient enough to enable extensive uncertainty quantification and sensitivity analysis. We quantify how uncertainties and variability in the input parameters, both experimental and theoretical, affect the force-displacement curves during approach and retraction. In addition, a sensitivity analysis quantifies the relative importance of the various input quantities for the prediction of force-displacement during contact closing and opening. The resulting force-displacement curves with quantified uncertainties can be directly used in device-level simulations of micro-switches and enable the incorporation of atomic and mesoscale phenomena in predictive device-scale simulations.

Dynamic modelling of wear evolution in rolling bearings

“…More details of the deformation of asperity can be found in [50,51]. Abrasive wear depends on the lambda ratio (i.e.…”

Error correction in multi-fidelity molecular dynamics simulations using functional uncertainty quantification

“…Uncertainty quantification (UQ) is becoming increasingly important in predictive simulations of materials and devices [1]. While the majority of the early UQ work focused on solid and fluid mechanics, there is growing interest in applying and extending UQ techniques to simulations at the material level, including density functional theory [2,3], molecular dynamics (MD) [4,5,6,7,8], and multiscale methods [9,10,11]. These efforts highlighted the importance of acknowledging uncertainties in model parameters, from measurement or averaging techniques, as well as intrinsic variability of the systems or processes under investigation.…”

Computational homogenization of soft matter friction: Isogeometric framework and elastic boundary layers

“…Because of the complex molecular structure of soft matter, the domain of modeling often lies in continuum mechanics, and in view of the highly nonlinear response (see below), the finite element method appears to be the most relevant numerical technique. For hard materials such as metals, on the other hand, a wider range of modeling and simulation choices are available for the multiscale analysis of contact in addition to the finite element method , such as molecular dynamics , the discrete element method , and the boundary element method , as well as semi‐analytical methods .…”