The Seismic Effect Reduction Test And Numerical Simulation On The Spring Vibration-isolated Foundation Of Turbo-generator

The spring vibration isolation as a kind of effective isolating vibration measures have been widely used in the turbo-generator foundation, it has obvious advantages in the alleviating of vertical vibration load from the generator unit, eliminate dynamic coupling of the foundation. For any of the spring vibration-isolated foundation, using the method of model test to verify it’s dynamic performance can make up for the lack of theoretical analysis and numerical simulation. In addition, the influence on foundation’s anti-seismic performance from the introduction of spring vibration isolator also needs to be explored based on model test. Therefore, a 1:8 scale model was established based on the 2*1000 MW turbo-generator foundation with spring vibration isolation from Laiwu power plant in this article, and following studies were carried out:(1) Based on the LMS software, three point excitation and three directional response acquisition methods were used to measured and analyzed the natural vibration characteristics, included the natural frequencies, mode shapes and damping ratios.(2) Hammer hitting method was used to test the dynamic stiffness of bearing block where has disturbing point, and the test result was compared with the manufacturer’s standard to verified the bearing block’s deformation performance in resisting dynamic loading.(3) The response of the upper and lower surfaces of the spring vibration isolator were collected under vertical excitation in this model, the vibration isolation efficiency and the transfer coefficient were calculated.(4) The spring vibration isolated model and the rigid foundation model with the same size were established based on ANSYS finite element software, and the natural vibration characteristics of the structure were analyzed and compared, to verified the superiority of the spring vibration isolated foundation.(5) In the pseudo dynamic testing,7 degree frequently occurred and 7 degree rarely occurred artificial earthquake waves were loaded on the structure, and the seismic response of the structure was collected, including platen’s acceleration, speed, and restoring force, displacement of the main position, steel strain, story drift ratios, spring deformation and crack development. All of this were to explored the seismic performance of spring vibration -isolated foundation.The analysis proved that the spring vibration isolated foundation can give full play to the advantages of the dynamic characteristics and seismic performance of the structure. The Spring vibration isolator reduces the natural frequency of the structure, Separates the vibration between the plate and the column. The distribution of internal force of foundation column are optimized, the foundation has a good performance to resistance the vertical generator unit load and horizontal seismic effect.