An analytical model for transient deformation of viscoelastically coated beams: Applications to static-mode microcantilever chemical sensors

S. M. Heinrich, M. J. Wenzel, F. Josse, I. Dufour
2009 Journal of Applied Physics  
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
more » ... me 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 ͑1͒ the time histories of the beam curvature and the coating stresses, ͑2͒ a criterion governing the response type ͑monotonic or "overshoot" response͒, and ͑3͒ simple expressions for the overshoot ratio, defined as the peak response scaled by the steady-state response, and the time at which the peak response occurs. Applications to polymer-coated microcantilever-based chemical sensors operating in the static mode are discussed.
doi:10.1063/1.3148291 fatcat:prn3wrdcmvcn7i6ulduuhzmipy