Custom specification under request:
SHIVA is capable of shearing ring-shaped samples at sliding velocities up to 9 m/s, accelerations of 40 m/s2 and normal stresses up to 50 MPa.
INGV performs experiments on rock samples of a variety of compositions using slip velocities and accelerations that simulate slip velocities function that occur during earthquakes.
In addition, TEES srl develop a pore fluid system and a pressure vessel in order to perform experiments that include the physical-chemical processes that occur during slow interseismic periods.
With this apparatus INGV is able to simulate the transient load variation expected during seismic failure on natural faults and measure the related dynamic weakening, frictional evolution and slip velocity on the sample.
TEES designed and manufactured for INGV the prototype rock deformation biaxial apparatus to examine the physical properties of brittle rocks.
The apparatus is installed in the HP-HT lab at the INGV in Rome.
The machine (about 6Tons weight) consists of a stainless steel pressure vessel with internal diameter of 40 cm, equipped with 2 hydraulic pistons, horizontal for normal stress and vertical for shear stress.
The vessel was designed to be and maintain an internal pressure up to 850bar.
Five holes on the pressure vessel allow to connect up to 100 sensors close the sample when the portholes are closed.
Pistons are driven by two very sensitive voltage control signals servo-valve and can work independently in load or displacement feedback control, obtaining a sliding velocity into the range 0.1 μm/s – 2 cm/s between the samples.
Two load cells with a dynamic load ranging up to 150 Tons and 30Kg of sensitivity are mounted onto each vertical and horizontal pistons.
The apparatus has other three hydraulic pistons positioned on the kart, that operate as fluid pressure intensifier and they are controlled by three proportional valves.
The apparatus has other three hydraulic pistons; two are dedicated for the pore fluid circulation into each sample rock. One piston intensifier is used to keep the confining pressure of oil around to the sample.