Long Travel Extensometers for Universal Testing Machines

Products > Accessories > Extensometers > Long Travel

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High-Elongation Strain Measurement for Elastomers, Films & Textiles

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Long Travel Extensometers are compatible with ANY Universal Testing Machine

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Long-Travel Extensometers — Accurate strain measurement for highly extensible materials

Overview

Long-travel extensometers are strain and displacement measurement devices engineered for specimens that undergo large elongations — such as elastomers, flexible plastics, films, textiles and leather. They extend the range of standard extensometers by providing much longer travel so you can measure through break or large strains without losing resolution or accuracy. Leading applications include tensile testing, fatigue, flex/bend, fracture and shear testing of soft and highly elastic materials.

Key capabilities to expect

• Large travel ranges — long-travel units commonly measure hundreds of millimeters of displacement, so they’re suited to tests that reach high strain before break. Always compare the travel spec to your expected elongation percentage. 

• Adjustable gauge length — most designs allow gauge length settings from small values (10 mm or so) up to several hundred mm, enabling standards-compliant modulus or secant-modulus calculations at the specified initial gauge length.

• Contact and non-contact options — contact (clamp-on) long-travel extensometers remain common for reliable direct displacement measurement; high-precision video/non-contact systems are available when clamping is impractical or sample surfaces are delicate. 

• High resolution and robust mechanics — premium designs use low-friction carriages, impact-resistant measurement systems and over-travel protection to avoid damage during “whiplash” failures and ensure repeatability. 

Typical applications & specimen types

• Elastomers and rubber (tensile, tear, flex)

• Flexible plastics and films (puncture, elongation to break)

• Textiles and leather (elongation, fatigue)

• Composites and certain plastics when high elongation occurs
  Long-travel extensometers are particularly useful when tests must proceed to large strains or to specimen failure while maintaining continuous, accurate displacement measurement.

How they measure — contact vs non-contact

• Contact (clamp-on) long-travel extensometers clamp to the specimen at the gauge points and mechanically track elongation. They’re generally simple to mount, rugged and well suited to rubber and other materials where firm clamping is acceptable.

• Non-contact (video/digital) extensometers use image processing to compute gauge-length changes. They are ideal for delicate surfaces, specimens that twist, or setups where clamping alters the test result. Non-contact systems can provide high precision across wide ranges when properly set up. 

Important technical specifications to compare

When selecting a long-travel extensometer, compare the following specs to your test requirements:

• Maximum measurement travel (∆L + L₀) — choose a travel range comfortably larger than the maximum expected elongation.

• Initial gauge length range & adjustability — ensure the device supports the gauge length(s) needed for your standards or internal procedures.

• Resolution / accuracy class — look for stated resolution (µm) and accuracy class for modulus or secant-modulus calculations. Higher precision is essential for materials where small strain differences matter. 

• Maximum tracking speed — if you run fast tests, confirm the extensometer’s maximum tracking speed (mm/min) so the device can follow the specimen without lag. 

• Over-travel protection — devices that include mechanical or electronic over-travel protection reduce the risk of damage in high-elongation or break scenarios. 

• Mounting method & frame compatibility — confirm clamps, mounted arm design, zero-stop features and compatibility with single-column or dual-column frames — quick and repeatable mounting saves lab time and reduces variability. 

Durability & test reliability features

• Low-friction carriage and robust guides reduce transmission error and improve repeatability during large elongations. 

• Impact-resistant components and design choices that handle specimen whiplash at break ensure fewer service events and more consistent data. 

Choosing contact vs non-contact (quick guide)

• Choose contact if: specimen can be clamped securely, simple repeatable mounting is required, and ruggedness is a priority.

• Choose non-contact if: the specimen surface is delicate, twisting occurs, or you need to measure complex deformation without affecting the sample.

Installation & best practices

• Use the zero-stop or pre-set gauge length feature (if available) to simplify mounting and ensure consistent initial position. 

• Match the gauge length to the test standard or the portion of the specimen you intend to analyze.

• Verify maximum tracking speed and resolution for your test speeds; perform a verification test to confirm expected accuracy before production runs. 

Comparison checklist (what to ask your extensometer supplier)

• What is the maximum travel and how is it specified? (∆L + L₀ or travel beyond gauge length?)

• What gauge length settings are available and how repeatable is the setting?

• What resolution and accuracy class is guaranteed?

• Is there over-travel protection and what form does it take?

• How easy is mounting/removal? Are spare clamps/gauge rods available?

• Is the unit frame compatible with your test machine and control software?

• Are video/non-contact options available and what are the environmental/light requirements for reliable imaging?

FAQs

Q: Can a long-travel extensometer measure through specimen break?
A: Yes — long-travel designs are intended to measure up to and through break for highly extensible materials; verify travel and over-travel protection to avoid damage. 

Q: Are video extensometers accurate enough for modulus calculations?
A: Modern high-precision video extensometers can provide accuracy suitable for many modulus and elongation measurements — confirm the stated class/specs and test with calibration specimens. 

Q: Will the extensometer damage soft specimens?
A: Contact clamps can indent delicate samples; use appropriate clamp designs or non-contact methods when specimen integrity is critical. 

Conclusion & next steps --> See Products Below

Long-travel extensometers extend your measurement capability for high-elongation materials while preserving resolution and repeatability. When selecting a unit, match travel, gauge length, accuracy and mounting compatibility to your test standards and typical specimens. If you’d like, we can help you define the exact spec sheet for your applications (expected maximum elongation, typical gauge lengths, test speeds, and whether you need contact or non-contact measurement) and provide a tailored recommendation.​​​​