Rock On-Specimen Measurement
GCTS offers advanced solutions for on-specimen measurement of various properties.
The Rock Deformation Devices measure axial and average radial strain directly on specimens using axial LVDT holder rings (DEF-AXC-R) and a circumferential chain device (DEF-RCP). Suitable for specimens Ø25 mm to Ø150 mm, these devices work within high-pressure (210 MPa) and high temperature (200 °C) triaxial cells temperatures. They determine elastic constants like Young’s modulus and Poisson’s ratio and can analyze post-failure inelastic strains. When integrated with GCTS servo control units and load frames, they enable direct control of axial or radial strain.
The DEF-CAN Diametral Deformation Device replaces the circumferential chain with a cantilever bridge, measuring radial strain in two planes. It features a single ring with four sensor arms, each equipped with strain gauges, to measure diametral deformations. This setup is easily adjustable for various specimen diameters and is compatible with high pressure (210 MPa), high temperature (200 °C) triaxial cells or unconfined settings.
The DEF-UNC is a complete, purpose-built kit designed exclusively for unconfined compression (UNC) testing of rock specimens. It combines precision axial strain measurement rings, a radial strain fixture, and the dedicated DEF-TWR deformation tower for rapid, repeatable assembly. Available in lightweight composite or durable aluminum, the axial and radial components deliver accurate on-specimen strain data while the tower ensures consistent gauge length and 180-degree sensor alignment every time. Ideal for laboratories that demand speed, repeatability, and reliable results in unconfined environments.
- Axial Strain (DEF-AXC-R)
- Radial Strain (DEF-RCP)
- Cantilever (DEF-CAN)
- Unconfined Compression (DEF-UNC)
Axial Strain (DEF-AXC-R)
HIGHLIGHTS
- Measures axial strain directly on the test specimen
- Available for specimens from Ø25 mm to Ø150 mm
- Two axial sensor supports
- Can be used for unconfined or confined testing
- Uses two LVDTs for ease of operation. LVDTs can be provided for high pressure (210 MPa), high temperature (200 °C)
- Very easy to set up and use
Radial Strain (DEF-RCP)
HIGHLIGHTS
- Measures radial strain directly on the test specimen
- Available for specimens from Ø25 mm to Ø150 mm
- One circumferential chain device
- Can be used for unconfined or confined testing
- Uses one LVDT for ease of operation. LVDTs can be provided for high pressure (210 MPa), high temperature (200 °C)
- Very easy to set up and use
Cantilever (DEF-CAN)
HIGHLIGHTS
- Direct measurement of specimen diametral deformation using paired strain-gauge sensor arms
- Measurement of diametral changes at two mutually perpendicular locations
- Suitable for use in confined (triaxial) or unconfined conditions
- Adjustable mounting via long screws (with optional springs) for rapid adaptation to the specimen diameter range
- Sturdy construction that minimizes risk of device damage during installation and testing
- Compatible with GCTS Reusable Membranes and electrical feedthrough connectors for high-pressure applications
- Enables integration of accessories for concurrent cross-diametral permeability or ultrasonic velocity measurements
Unconfined Compression (DEF-UNC)
HIGHLIGHTS
- Complete kit: DEF-AXC axial strain rings + DEF-RAD radial fixture + DEF-TWR assembly tower
- Choice of composite or aluminum construction for the axial and radial setups
- Designed exclusively for unconfined (UNC) testing
- Fast, precise mounting with consistent gauge length and 180° sensor alignment
- Compatible with Ø25 mm (1″) to Ø63.5 mm (2.5″) specimens
- Dramatically reduces setup time and operator variability
- Stable, purpose-built tower minimizes alignment errors for high-quality axial and radial strain data
