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Full-Text Articles in Civil and Environmental Engineering
An Analytical Model For Transient Deformation Of Viscoelastically Coated Beams: Applications To Static-Mode Microcantilever Chemical Sensors, Stephen M. Heinrich, Michael J. Wenzel, Fabien Josse, Isabelle Dufour
An Analytical Model For Transient Deformation Of Viscoelastically Coated Beams: Applications To Static-Mode Microcantilever Chemical Sensors, Stephen M. Heinrich, Michael J. Wenzel, Fabien Josse, Isabelle Dufour
Civil and Environmental Engineering Faculty Research and Publications
The problem governing the transient deformation of an elastic cantilever beam with viscoelastic coating, subjected to a time-dependent coating eigenstrain, is mathematically formulated. An analytical solution for an exponential eigenstrain history, exact within the context of beam theory, is obtained in terms of the coating and base layer thicknesses, the elastic modulus of the base material, the initial coating modulus, the coating relaxation percentage (0%–100%), and the time constants of the coating’s relaxation process and its eigenstrain history. Approximate formulas, valid for thin coatings, are derived as special cases to provide insight into system behavior. Main results include (1) the …
Effect Of Coating Viscoelasticity On Quality Factor And Limit Of Detection Of Microcantilever Chemical Sensors, Isabelle Dufour, Frederic Lochon, Stephen M. Heinrich, Fabien Josse, Dominique Rebiere
Effect Of Coating Viscoelasticity On Quality Factor And Limit Of Detection Of Microcantilever Chemical Sensors, Isabelle Dufour, Frederic Lochon, Stephen M. Heinrich, Fabien Josse, Dominique Rebiere
Civil and Environmental Engineering Faculty Research and Publications
Microcantilevers with polymer coatings hold great promise as resonant chemical sensors. It is known that the sensitivity of the coated cantilever increases with coating thickness; however, increasing this thickness also results in an increase of the frequency noise due to a decrease of the quality factor. By taking into account only the losses associated with the silicon beam and the surrounding medium, the decrease of the quality factor cannot be explained. In this paper, an analytical expression is obtained for the quality factor, which accounts for viscoelastic losses in the coating. This expression explains the observed decrease of the quality …
Effect Of Viscoelasticity On Quality Factor Of Microcantilever Chemical Sensors: Optimal Coating Thickness For Minimum Limit Of Detection, F. Lochon, Isabelle Dufour, D. Rebière, U. Sampath, Stephen M. Heinrich, Fabien Josse
Effect Of Viscoelasticity On Quality Factor Of Microcantilever Chemical Sensors: Optimal Coating Thickness For Minimum Limit Of Detection, F. Lochon, Isabelle Dufour, D. Rebière, U. Sampath, Stephen M. Heinrich, Fabien Josse
Civil and Environmental Engineering Faculty Research and Publications
Microcantilevers with polymer coatings hold great promise as resonant chemical sensors. It is known that the coated cantilever sensitivity increases with coating thickness; however, the drawback of increasing the coating thickness is the increase of the frequency noise and thus the deterioration of the sensor's limit of detection. In this paper, an analytical expression for the viscoelastic losses in the coating, hence the quality factor is established and is used to explain the observed increase of the frequency noise with the polymer thickness. This result is then used to demonstrate that an optimum coating thickness exists that minimise the limit …