Methodology of calculation of the dynamics of the system turbine-foundation-base power units under seismic actions

Анотація

The creation of powerful turbine units of nuclear power plants requires an assessment of the structure response to seismic action. For analysis of dynamic processes in the turbine units under seismic actions is necessary to be taken into account the interaction of the turbine unit and foundation. Method and software for analysis of turbine-foundation-base system under seismic action are proposed. The software package is based on the finite element method with the direct integration of the motion equations by Newmark’s or Vilson’s method. The rod computational models for solve problems forced flexural, longitudinal, torsional vibrations and transients shafting on complex elastic-damper supports are used. The foundation plates are modeled by of the rods grating that take into account elasticity and inertial properties of foundation elements. The lumped mass at the nodes of rods of foundation are used to account for the mass of the installed equipment and pipelines. The problem of non-stationary dynamic analysis of forced vibrations is solved in the mobile coordinate system associated with the foundation. The accelerations of foundation in three perpendicular directions are specified by using digitized real or synthesized accelerograms. The symmetric matrices of a special structure are used to achieve high performance in the calculations. Created graphical interface allows to visualize the geometry of the structure, its discretization into finite elements, deformation at different times, the graphics of displacement vs. time, velocity and acceleration of individual construction points, as well as forces in the elastic connections. The stresses in elastic connections, their maximum and minimum values and the time of their occurrence are determined for evaluation of strength of the turbine-foundation-base system. The results of analysis of turbine К-1100-23.5 for different design models are shown.