ABSTRACT A vibration isolation system using spring units and visco ...

3.1.2 Cyclic horizontal loading test
(1) Loading
At first the spring unit is deformed vertically by - 20 mm, - 10 mm (tension), 5 mm, 15 mm, 40 mm
(compression). Then the unit is pushed in two horizontal directions in a right angle by a cyclic load
of a hydraulic jack.
(2) Displacements
The horizontal displacement is ± 10 mm in the first cycle, ± 20 mm in the second cycle, ± 30 mm in
the third cycle and ± 42 mm in the forth cycle.
(3) Results
Fig. 5 shows the relation between horizontal load and displacement.
Fig. 6 shows the relation between horizontal spring rate and vertical displacement.
According to Fig. 6, the horizontal spring rate increases with increasing vertical displacements. The
results are the same in both horizontal directions.
Fig. 5 Horizontal load-displacement line Fig. 6 Relation between horizontal spring rate
and vertical displacement
3.1.3 Cyclic vertical loading test
(1) Loading
At first the spring unit is deformed horizontally by 0 mm, 30 mm, 42 mm. Then the unit is
dynamically loaded in vertical direction cyclically by a hydraulic jack.
(2) Displacements
At first the spring unit is compressed statically by 40 mm. Then it is vertically loaded by ± 20 mm in
the first cycle, ± 30 mm in the second cycle, ± 40 mm in the third cycle and ± 50 mm in the fourth
cycle.