Determines small-strain shear modulus (Gmax) and material damping (D) of soils using torsional (and optional longitudinal) resonance under controlled confinement and drainage conditions.
Fixed-base architecture with electromagnetic drive and non-contact motion pickup enables clean frequency sweeps, automatic resonance tracking, and half-power bandwidth damping evaluation with high signal-to-noise.
Supports saturated and unsaturated testing workflows with cell and back-pressure control for drained/undrained states, including B-value verification during setup.
Wide dynamic range covers very small shear strains (~10⁻⁶–10⁻⁴) in resonant column mode; optional torsional shear mode extends characterization to higher strains for modulus/damping degradation curves.
Integrated software automates saturation and consolidation staging, frequency step/sweep, amplitude control, resonance identification, and generation of Gmax and D versus shear strain plots.
