Schenck Machine testing at TARRC
Schenck Machine testing at TARRC

The POZ Schenck with its Instron controller is the largest servo hydraulic machine in regular use in the Engineering Department at TARRC. It was originally acquired for a successful development project for natural rubber laminated bearings for protecting structures from earthquakes. It is now also used to test large seismic bearings designed to support buildings in earthquake-prone regions, to test large isolation bearings designed to support structures affected by foundation transmitted disturbances at various frequency-dependent amplitudes and to test bridge bearings designed to accommodate horizontal expansion and contraction whilst supporting a vertical load.

Typical tests carried out in the vertical axis include quasi-static compressive stiffness tests and dynamic stiffness tests. The dynamic stiffness tests are conducted over a range of vertical pre-loads with superimposed low-amplitude dynamic loads at frequencies up to typically 25Hz. It is also possible to conduct combined vertical axis and horizontal shear axis tests to determine the shear stiffness of a bearing when under vertical load, using a fully biaxial servo-controller.

The machine vertical capacity is 2.5MN (250 tons compression and tension) with +/-50mm stroke. The machine horizontal capacity with one of its two side rams is 100kN (10 tons shear) with +/-150mm stroke) and with the other side ram is 400kN (40 tons unidirectional shear) with 440mm stroke or +/-250kN (25 tons bi-directional shear) with +/- 220mm stroke.

The POZ Schenck has recently been used to successfully test several of the largest resilient mounts ever attempted on this machine when considering the overall physical size of the resilient mounts and the combined vertical and horizontal loads and deflections that were required.

The resilient mounts that were designed and manufactured by the same customer who requested the tests at TARRC were to form part of a set of mounts capable of supporting a large marine vessel in a docking cradle. Each of the resilient mounts weighed around 250Kg (about one quarter of the weight of a family car) and the overall dimensions were 930 x 540 x 275mm. Each had to undergo vertical compressive stiffness tests up to 2000kN (something like the equivalent weight of 16 fully-laden double-decker buses) and it took 250kN (something like the equivalent weight of two fully-laden double-decker buses) to shear the top plate of the resilient mount 220mm with respect to the bottom plate whilst under a 1000kN vertical load.

The test set-up also incorporated a large roller bearing designed at TARRC and coupled to load-cells that measured the true shear load by eliminating the friction load component which arose as the resilient mount moved horizontally below the Schenck vertical hydraulic actuator.

It is believed that TARRC may be one of the few establishments remaining in this country with the capability to routinely undertake the type of tests outlined above within the range of the loads and deflections as described.

For more information about Schenck machine testing at TARRC please contact Roy Bowron.



© Tun Abdul Razak Research Centre 2005
January 2009