• Uniaxial, compression-tension creep-fatigue tests on all types of materials under low (down to liquid helium temperature, -269°C) or high temperature (up to 1300° C).
  • Biaxial, compression - tension - internal pressurisation creep-fatigue tests (up to 1300°C) on tubular specimens (ceramic, metallic, composite, etc.).
    Use of the patented CTIP compression-tension-internal pressurisation machine.
  • Shear, cyclic through zero loading tests at low, room and high temperatures (1600 °C).Use of the patented shear machine.
  • Combined, shear-tension creep-fatigue tests.
    Use of an upgraded version of the shear machine.
  • Thermal shock tests on specimen subjected to simultaneous mechanical loading. Ascending (up to 1200 °C) or descending (down to 4K) thermal shock tests can be performed.
  • High-frequency resonant tests on piezoelectric actuators (stack actuators and piezopatches) using the Piezoelectric Testing Array.
  • Multiaxial tests on large specimens and structures using the Large-Scale Testing Machine. The use of an IMMG patented piezoelectric actuation servovalve allows high-speed testing of large and elongated structures.
  • Seismic tests on scale-down prototypes of buildings using the U-D shaking table. 

FATIGUE AND HIGH SPEED TESTING

Through years of experimentation in the field of mechanics of materials and structures, IMMG has developed a special piezoelectric servovalve that allows high frequencies to be attained (up to 400 Hz) in servo-hydraulic testing machines, in a reliable and perfectly controllable way. This product can substitute a solenoid servovalve and greatly enhance the dynamic response of the system.

The piezoelectric servovalve has been successfully incorporated in the CTIP and Shear machines and has expanded their fatigue testing capabilities which include :

  • Fatigue testing on many material categories at temperatures ranging from cryogenic (-269 C) to high (1200 C) temperatures.
  • Fatigue testing of GFRPs and CFRPs
  • Simulation of impact testing on steels and geomaterials
  • Simulation of seismic action on steel bars and reinforced concrete beams and columns.

HIGH FREQUENCY PZT TESTING AT RESONANCE

IMMG has developed a testing array dedicated to testing of PZT actuators at a selected resonance frequency. The time-depended performance and long-term reliability of stack-type or patch-type actuators is assessed using special high-frequency, high-power electronic equipment for controlling the input to the actuators, high-resolution laser or fiber optic displacement transducers for measuring the kinematical response and high accuracy miniature force transducers for measuring the dynamical response of these systems in real time.

MULTIAXIAL TESTING OF LARGE-SCALE STRUCTURES

This large facility (spanning in two floors of the IMMG laboratory) is able to generate and control high loads and displacements at high speeds up to impact on specimens or components or large structures. This is achieved by using a high capacity hydraulic pump in parallel with two large hydraulic actuators to provide the needed power and a combination of high-flow capacity servo-valves (standard and piezoelectric) to control the flow. Impact velocities up to 120 m/s and impact forces up to 10MN (~1000 ton) have been achieved at loading rates as high as 4GN/s. The facility has the ability to accommodate large structures up ?900 x 3500 mm (cylindrical) and 4000 x 2000 (height) x 900 mm (orthogonal). Local and overall load or strain control can be accurately attained, using motion controllers and highly improved software. Large GFRP and CFRP honeycomb sandwich panels for a number of applications including space structures for ESA have been tested in this facility in combined in-plane and out-of-plane bending and shear.

HIGH TEMPERATURE CRACK-GROWTH MONITORING

IMMG has developed a modified potential drop technique for conducting on-line crack growth (Mode II and combined Mode I and II) monitoring at high temperature. Electrodes and sensors are placed at specific locations on the surface of an electrically conductive shear specimen and the recorded results are processed on-line using numerical results from FEA simulation to obtain true on-line versus crack-growth graphs (Paris’ charts), without interrupting the test. The technique has been implemented for different material categories including measuring crack growth in nickel based superalloys at high temperature.

LARGE SCALE DYNAMIC TESTING, SEISMIC EXPERIMENTS

IMMG developed a shaking table for testing prototypes of civil-engineering structures under simulated uniaxial earthquake conditions. The platform of the shaking table was manufactured by IMMG, according to the patented DIRIS architecture. Its weight is only 210 kgr but its specific shear and tensile strength is the highest available. The shaking table measures 4 m x 3 m and it is able to accommodate either full-size or half-size prototypes of large structures having mass up to 10 Ton. Acceleration up to 7g, and and displacement up to ± 120 mm can be achieved. Seismic loading experiments on a numerically examined small masonry building are currently performed.