Clip-on, video, automatic or furnace extensometers – for all your mechanical tests

Extensometry – Strain and displacement measurement

What is extensometry?Extensometry enables the measurement of localized strain or displacement on a material subjected to tensile, compression, flexural or peel testing.
3R offers a wide range of mechanical, automatic or video extensometers, suited to each type of test and material.

Why use an extensometer?

An extensometer enables:

• Precise monitoring of strain over a targeted zone,
• Controlling a test at strain or opening rate (e.g. crack),
• Objectively comparing samples,
• Capturing the actual behavior of the material, independent of machine compliance,
• Working on fragile specimens, flexible materials, or over large displacement ranges

Types of tests achievable with extensometry

• Tensile testing on metals (modulus measurement, elongation at break)
• Tensile testing on polymers, composites (elastic and plastic behavior)
• Compression (instability, transverse strain)
• Flexural testing 3 and 4 point (central or average deflection)
• Behavior at temperature (hot metals, polymers)
• Measurement on long structures or rebar (elongation over large gauge length)

3R extensometer range: a solution for every need

The 3R extensometer range meets all standard requirements in terms of strain and displacement.

Models	Features	Learn more
Clip-on Extensometers	Quick mounting on flat or cylindrical specimensIdeal for standard tensile tests, modulus E, elongation, standards ISO 9513, SI6892, ISO15630, ASTME8 etc… Thermal versions from -273°C to +200°C	Clip-on extensometers
Automatic arm extensometers	Tests on elastomers, composites, flexible polymersUse in laboratory with high repeatability Suitable for flexible tensile or 3-point flexural tests	Automatic extensometers
Furnace extensometers	Temperature measurement up to 1000 °CIdeal for tests on metals, ceramics, superalloys Retraction system for protection during temperature rise	High-temperature extensometers
Video extensometers	Non-contact measurement (strain, cracking, peeling)Visual monitoring of multiple zones simultaneously Easy integration with control software	Video extensometers
Laser extensometers	Optical measurement at distance, by laser triangulation or interferometryIdeal for fragile materials, large strains or inaccessible surfaces: tensile tests on ropes, elastomers, polymers, adhesives Suitable for hot tests	Laser extensometers
Concrete and steel extensometers	For tests on rebar, couplers, anchorage failuresMeasurement over large gauge lengths from 95 to 975 mm Compatible with clamps or on-site clamping systems	Civil Engineering extensometers
Displacement sensors (LVDT / deflectometer)	High-resolution external measurement Ideal for rigid structures, beams or composite materials