Based on experimental tests at the test rig actual dynamic features of each type of damper have been obtained. Experimental data confirms that elastic and viscous components of dynamic stiffness considerably depend upon frequency. Such a damper dynamic behavior can be described by linear system consisting of two parallel Maxwell circuits (spring damper).

Mathematical model of visco-elastic damper (Ce - elastic component, Cv viscous component, Cs - equivalent dynamic stiffness)

 

The model is described with four independent parameters (K1, K2, B1, B2), the change of which leads to good agreement between the results and experimental relations.

To perform calculation analysis for pipeline systems CKTI-VIBROSEISM developed dPIPE software system.

 

a) Installation of VD dampers on the primary circuit of VVER-1000 NPP. Results of seismic analysis: b) prior to dampers installation; c) after dampers installation.