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.