Installation of Shake Table Facility


  Seismic Table:    
  The Seismic Table has a linear hydraulic actuator with a fatigue rating of 110 kip (500 kN). The actuator is attached to a 3 M x 3 M table which is guided by linear bearings. The stroke capability of the unit is 300 mm ( 12 inch) with a nominal peak velocity of 1 meter/sec (40 inches/sec) and average velocity of meter/sec (20 in/sec). The linear guide bearing are sized to test a 20 MT payload with a CG 3 M off the table surface, with 60 MT-M over turning moment at one g. The entire table assembly is attached to the mass via the post tensioned steel plates on the mass top surface. The actuator is attached to the moving table via a coupling flexure which is guided by linear bearings.

The table surface includes a mounting grid pattern to simplify specimen attachment. The assembly has a complete with a servo valve 900 lpm (240 gpm) and position transducer to allow displacement to be used as the feedback for loop closure. An accelerometer is used to control or monitor the table motion in an external loop as well. The control system accepts a signal from the control system. The hydraulic power is provided via a 156 gpm, 3000 psi HPS.

The Siesmic Table Assembly is attached to a reaction mass in order to develop full force performance. A mass to maximum load ratio is 20:1.

The systems include control software which all standard features. The System has four (4), 32 bit input A/D channels with 16 bit programmable attenuators, one, 64-bit output D/A channel with 16-bit D/A, one, high speed signal processing module, classical shock vibration and a 2.93 GHz PC based computer.

Hydraulic Linear Actuator, 500 kN (110 kip), is a double ended fatigue rated, with hydrostatic and replaceable non-metallic back up bearings, one-piece 133.4 mm (5.25 inch) heat treated alloy piston rod, and internal, concentrically mounted LVDT. Hydrostatic bearing provide a low friction high side load bearing to assure low harmonic distortion during high velocity tests.


Back To Department Website