Electro-Mechanical Analysis Involving Stochastic Contact Hypothesis in Engineering


CALL: 2008

DOMAIN: MS - New Functional and Intelligent Materials and Surfaces






KEYWORDS: electro-mechanical contact

START: 2009-01-01

END: 2011-06-30

WEBSITE: https://www.list.lu/

Submitted Abstract

In the framework of this project, the modelling of electric current flow will be implemented in an inhousesolid mechanics finite element code. Contact constitutive laws based on existing stochasticmicromechanical models, which derive the true microscopic contact surface from surface roughnessparameters, material parameters and mechanical pressure, like for example Greenwood-Williams orCooper-Mikic-Yovanovich models, will be implemented, both for the mechanical pressure transferbetween surfaces as well as for the flow of electric current between surfaces. Emphasis will be put onmicromechanical models taking into account permanent surface asperity flattening by plasticdeformation. The resulting finite element code will give access to a coupled electric-mechanical contactresistance analysis. Sensitivity analysis based on direct differentiation will be implemented in order toobtain the sensitivities of the governing field variables, like mechanical displacement or electric current,with respect to statistical parameters characterizing microscopic surface geometry like mean surfaceroughness, asperity size, asperity slope or distance between asperities.The electromechanical contact finite element analysis and the sensitivity analysis enable the analysis oflocal electric current transfer between two surfaces in electromechanical contact and the quantification ofthe influence of locally varying surface roughness or conductivity.The sensitivity analysis will be used in two ways. On the other hand, the sensitivity analysis offers thepossibility to investigate and assess experimental procedures for identifying surface roughnessparameters from pressure versus electric current recordings. By approximating the correlation matrixfrom first order derivatives, it can be evaluated if the aforementioned surface parameters can be identifieduniquely and reliably. On the other hand, pressure sensors based on electric current flow between twomembranes covered with a conducting layer will be analyzed. The finite element code and sensitivityanalysis will be used to assess the possibility of improving their response characteristics by modifying thelocal resistance to electric current transfer between surfaces by a tailored, locally varying surfaceroughness or conductivity of the conducting layer.

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