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Nanoscale Metal-Metal Contact Physics From Molecular Dynamics: The Strongest Contact Size, Hojin Kim, Alejandro Strachan
Nanoscale Metal-Metal Contact Physics From Molecular Dynamics: The Strongest Contact Size, Hojin Kim, Alejandro Strachan
PRISM: NNSA Center for Prediction of Reliability, Integrity and Survivability of Microsystems
Using molecular dynamics we find that the tensile strength of the contacts between two clean platinum surfaces with nanoscale asperities is strongly size dependent with a maximum strength for contact lengths of approximately 5 nm. This is the first time a strongest size is observed in single crystals. The strengthening with decreasing size down to 5 nm results from a decrease in the initial density of mobile dislocations available for plastic deformation and the subsequent weakening originates from a reduction in the constraint to mechanical deformation inside the contact by the bulk.
A Numerical Fatigue Damage Model For Life Scatter Of Mems Devices, Behrooz Jalalahmadi, Farshid Sadeghi, Dimitrios Peroulis
A Numerical Fatigue Damage Model For Life Scatter Of Mems Devices, Behrooz Jalalahmadi, Farshid Sadeghi, Dimitrios Peroulis
PRISM: NNSA Center for Prediction of Reliability, Integrity and Survivability of Microsystems
This paper presents a fatigue damage model to estimate fatigue lives of microelectromechanical systems (MEMS) devices and account for the effects of topological randomness of material microstructure. For this purpose, the damage mechanics modeling approach is incorporated into a new Voronoi finite-element model (VFEM). The VFEM developed for this investigation is able to consider both intergranular crack initiation (debonding) and propagation stages. The model relates the fatigue life to a damage parameter "D" which is a measure of the gradual material degradation under cyclic loading. The fatigue damage model is then used to investigate the effects of microstructure randomness on …