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Nonlinear Highlights


Time Reversal Acoustics Experimental Facilities & Resources

Time Reversal Acoustics experiments are performed in our Nonlinear Elasticity Lab fully equipped for both quasi-static (measurements of stress-strain equation-of-state curves) and dynamic (wave propagation) experiments. The lab is equipped also for ultrasound imaging with different laser vibrometers and the experimental apparatus for resonant ultrasound spectroscopy.

Main Experimental Facilities

  • Polytec Scanning Laser Vibrometer (0-1.5 MHz)
  • Polytec Single Point Laser Vibrometer (0-1.5 MHz)
  • Polytec In-Plane Laser Vibrometer (0-1.5 MHz)
  • Motion Controlled X and Y Translational Stage Systems
  • HP 4192 LF Impedance Analyzer
  • Gage Data Acquisition Systems (3 - 8 Channel Generator Cards, 1 - 8 Channel Receiver Card, 8 - 2 Channel High Quality Receiver Cards)
  • Krohn-Hite Power Amplifiers (Single Channel)
  • ENI Power Amplifiers (Single Channel)
  • Artann RF Power Amplifiers (Ten Channel)
  • ADG Ultrasonic Welder
  • Ultraprobe 9000 Ultrasound Inspection Tool
  • Various Contact and Non-Contact Piezoelectric Transducers
  • Lock-In Amplifiers
  • Function Generators
  • Oscilloscopes
  • Press Instron 5569 (0-5kN and 0-30kN compression)

Computational Facilities and Resources

The group is equipped with High Performance Computing (HPC) resources for the modeling/simulation of elastic wave propagation in complex heterogeneous linear/nonlinear materials and in the earth. Numerical simulations are at the basis of the Time Reversal Computational Imaging technique used in our work: the Time Reversal backward propagation stage is simulated through a model of the propagation medium using as source signals the time reversed forward propagation signals measured during a forward propagation experiment with a lab specimen or the seismological signals measured by international seismological networks of stations around the world or in a specific region of the earth.

  Our High Performance Computing Resources

  • Beowulf Linux cluster, 31 nodes; each node is a Symmetric Multi Processor (SMP) unit made of 2 AMD dual-core processors and 8 Gbytes of memory/node; 800 GBytes of scratch disk space and 2 TBytes of storage disk space; MPICH libraries, Pathscale and GCC compilers for C/Fortran 90 programs;
  • 2 Dell Precision 690 workstations each of which is a 4 dual-core Intel Xeon 3.73 GHz Symmetric Multi Processor, used for data post processing and imaging analysis and processing.

  Our Simulation Software

  • MPI-enabled parallel spectral elements (SE) method computational codes for seismic wave propagation in the Earth;
  • MPI-enabled parallel finite difference (FD) method computational codes for elastic wave propagation in solid specimen;
  • Multi-threaded finite element (FE) software platform for MultiPhysics simulations (Comsol MultiPhysics 3.4);
  • Matlab, GMT (General Mapping Tools), SAC (Seismic Analysis Code), Octave, Scilab computing platforms for data analysis and post processing.


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