Application of Simulation Based Reliability Analysis on the Dimensioning of Viscous Dampers GERB

GERB pipework dampers are highly effective viscous – elastic elements applied in many conventional and nuclear power plants. The best approximation for the seismic analyses of safety related pipeworks is the application of double Maxwell model represented by spring stiffnesses k₁, k₂ and damping coefficients b₁, b₂. These parameters represent damper capacity C_N. Each damper is designed and manufactured for given operating temperature t₀ and experimentally obtained curves of pseudostiffnesses and damping coefficients as the function of frequency in the range of 〈0; 35〉 Hz. Two parameters influence reliability of damper under seismic event: Overloading of nominal capacity in kN and conservation of minimal gap between piston and damper housing. The probabilities of exceeding of related allowable values may be assessed using Simulation Based Reliability Analysis. The needed input parameters are capacity and actual loadings and displacement of a piston in horizontal direction. General theory and numerical example are presented.