Standard 25 mm
Pneumatic Vice Action Grip
Pneumatic vice action grips clamp the full strip width at a constant, even pressure, which is what stops one side of the fabric slipping or tearing before the other.
SpecificationsTesting standard
ASTM D5035
Standard Test Method for Breaking Force and Elongation of Textile Fabrics (Strip Method)
Written and technically reviewed by Dak System Inc. engineeringLast reviewed
ASTM D5035 measures the breaking force and elongation of a textile fabric using the strip method. A strip of specified width is clamped across its whole width and pulled to break, so every yarn in the specimen carries load. It contrasts with the grab method, where a narrower jaw grips only part of a wider specimen.
At a glance
- Test type
- Tensile — the specimen is pulled apart
- Published by
- ASTM
- Edition
- D5035-11
- Runs on
- Series 7200 and Series 9000
What the test does
A strip of fabric is cut oversized and then ravelled down to the test width — commonly 25 or 50 mm — so that only whole yarns remain across it. For fabrics that cannot be ravelled, such as nonwovens, felts and coated goods, a cut strip is used instead. The strip is clamped across its entire width in flat-faced grips over a gauge length of about 75 mm, given a small pretension to remove slack, and pulled at a rate that breaks it in roughly twenty seconds. Force is recorded against grip separation. Warp and weft directions are tested separately and reported separately.
What it measures, and why it matters
The outputs are breaking force and elongation at break, for a stated strip width and direction. Because the grips hold the full width, every yarn carries its own share of the load, which makes this the more direct measure of a fabric's intrinsic tensile strength. It is used to specify and accept woven and nonwoven fabrics across apparel, technical textiles, geotextiles and industrial goods, and to verify that a fabric will survive making-up, installation and service. Elongation matters alongside force, because a fabric that reaches its breaking load with very little give behaves quite differently in use from one that stretches.
Specimen
The strip method's defining feature is that the grips hold the entire width. That makes edge preparation part of the measurement rather than tidying up.
- Ravelled strip
- Cut wider, then ravelled to the test widthRavelling removes the cut edge yarns that would otherwise be partly severed and carry no load.
- Cut strip
- Used for non-ravellable fabricsNonwovens, coated fabrics and felts, where there are no yarns to ravel.
- Test width
- 25 mm or 50 mm as specified
- Gauge length
- 75 mm typical
- Directions
- Warp and weft tested separatelyWoven fabric is anisotropic by construction, and the two directions are different products.
- Conditioning
- 21 ± 1 °C and 65 ± 2 % RH
- Count yarns rather than measuring the width
- On loose weavesDakA ravelled strip of a loose fabric can be measured at different widths depending on how it is laid; counting yarns gives the same answer every time.
Strip and grab results are not interchangeable. In the strip method every yarn carries load; in the grab method the yarns beside the jaw help their neighbours, which raises the recorded force. A grab result is normally higher and the two must not be compared.
Test speed
- Rate
- Set to break in 20 ± 3 sFabrics range from a few per cent to several hundred per cent elongation, so a fixed speed will not do.
- Elongation
- From grip separation
- Pretension
- Small, to remove slack without stretching
- Watch for progressive yarn breakage
- A stepped traceDakA fabric whose yarns break in ones and twos gives a saw-toothed curve; the peak is still the breaking force but the shape says something about yarn uniformity.
Calculations
Breaking forceF
The maximum force recorded, in N
Reported for the stated strip width. It is not normalised to a stress, because fabric thickness is not a meaningful denominator.
Elongation at breakε
ε = ΔL / L₀ × 100
- ΔL
- increase in grip separation, mm
- L₀
- gauge length, mm
How the test runs
- 01Cut strips oversized in both warp and weft directions.
- 02Ravel each strip to the test width, or cut to width for non-ravellable fabrics.
- 03Condition at 21 ± 1 °C and 65 ± 2 % RH.
- 04Fit grips at least as wide as the specimen, with faces suited to the fabric.
- 05Set the gauge length.
- 06Mount the strip square, clamping the full width evenly.
- 07Apply a small pretension to remove slack.
- 08Set the rate to break in about 20 s.
- 09Pull to break, recording force and grip separation.
- 10Reject jaw breaks and specimens that slipped.
- 11Report warp and weft results separately.
The fixture this method needs
What the report has to contain
- Reference to ASTM D5035 and the edition
- Fabric identification, construction and mass per unit area
- Whether ravelled or cut strips were used
- Strip width and gauge length
- Direction — warp or weft — for each result set
- Grip face type
- Conditioning atmosphere and duration
- Rate used and time to break achieved
- Breaking force and elongation for each specimen
- Number rejected for jaw breaks or slippage
- Mean, standard deviation and coefficient of variation
What the machine must be capable of
Force measurement to ASTM E4 across a range from tens of newtons for light apparel fabric to several kilonewtons for industrial textiles, and a crosshead offering enough rates to achieve a twenty-second break on fabrics ranging from a few per cent elongation to several hundred. Grips must be at least as wide as the specimen and clamp evenly across it, which in practice favours pneumatic jaws over screw-tightened ones. Face selection is a real variable: smooth faces slip on coated goods while aggressive serrations cut fine fabrics. The laboratory needs the textile standard atmosphere, which is not the same as the general one.
What goes wrong in practice
Grip problems dominate, and they come in two opposite forms — slippage on slick fabrics and jaw breaks on delicate ones — with the cure in both cases being the face material rather than more pressure. Testing in the wrong atmosphere is a systematic error that a laboratory handling both plastics and textiles makes easily. Comparing strip results with grab results is the most consequential reporting mistake, since the two give different numbers on the same fabric and no fixed factor converts between them. On loose weaves, measuring rather than counting the ravelled width introduces an avoidable spread.
Strip method or grab method
| Strip (D5035) | Grab (D5034) | |
|---|---|---|
| Specimen width | Equals the clamped width | Wider than the clamped width |
| Load carried by | Every yarn in the specimen | Clamped yarns, assisted by their neighbours |
| Typical result | Lower | Higher |
| Better represents | The fabric's intrinsic strength | Fabric in use, where surrounding material helps |
Neither is more correct; they answer different questions and give different numbers on the same fabric. A specification naming one is not satisfied by the other, and the difference between them is not a fixed factor that can be applied to convert.
Questions we are asked about this test
What is ASTM D5035?
It is the ASTM strip method for the breaking force and elongation of textile fabrics. A strip of specified width — ravelled to width for woven fabrics — is clamped across its entire width and pulled to break, so every yarn in the specimen carries load. Warp and weft are tested and reported separately.
What is the difference between the strip and grab methods?
In the strip method the grips hold the whole specimen width, so each yarn carries its own load. In the grab method, ASTM D5034, a narrower jaw grips the middle of a wider specimen, and the yarns beside the jaw help carry load through the fabric structure. That assistance makes grab results higher on the same fabric. Neither is more correct — they answer different questions, and the difference is not a fixed factor you can convert with.
Why ravel the strip instead of just cutting it to width?
Because cutting through a woven fabric leaves partly severed yarns along both edges that cannot carry their full share of load. Ravelling removes those edge yarns entirely, so the strip that remains consists only of whole yarns. For nonwovens, felts and coated fabrics there are no yarns to ravel, and a cut strip is used instead — which is noted in the report.
Why is breaking force not converted into a stress?
Because fabric thickness is not a meaningful denominator. A woven fabric is mostly air, its measured thickness depends on the pressure used to measure it, and dividing by it would produce a number that varies with the gauge rather than the material. Breaking force for a stated strip width is unambiguous, and it is what fabric specifications are written in.
Why the 21 °C and 65 % RH atmosphere?
It is the textile standard atmosphere, and it differs from the 23 °C and 50 % RH used for plastics and most other materials. Natural and regenerated fibres change strength appreciably with moisture regain — cotton gets stronger as it takes up moisture, viscose weaker — so testing in the wrong atmosphere produces a consistent bias. It is one of the easiest mistakes for a general-purpose laboratory to make.
My specimens keep slipping in the grips. What should I change?
The grip faces before the pressure. Smooth faces slip on coated and slick fabrics, while aggressive serrated faces cut fine ones and cause jaw breaks instead. Matching the face to the fabric solves most cases — rubber-faced or lightly textured jaws for slippery goods, softer faces for delicate ones. Raising the pressure on a smooth face usually just crushes the fabric at the jaw line.
What does a saw-toothed force curve mean?
That the yarns are breaking progressively rather than together — a few give way, load redistributes, then a few more. It is common in fabrics with variable yarn strength or uneven tension in the weave. The peak force is still the breaking force, but the shape carries information the number does not: a fabric that fails in one clean drop has more uniform yarns than one that steps its way down.
Running ASTM D5035 on the Series 7200 and Series 9000
Dak verifies against whichever standard the method names, and where a class applies our frames sit a class tighter than it asks.
| The method asks for | Dak supplies | |
|---|---|---|
| Capacity | Low to moderate — from tens of newtons on light apparel fabric to several kilonewtons on industrial textiles | Load cells from 1 kg to 60 ton on the Series 7200, and 0.5 to 100 kN on the Series 9000 |
| Force accuracy | ASTM E4 | Verified to ASTM E4, and to ISO 7500-1 Class 0.5 |
| Gripping | Flat-faced grips at least as wide as the specimen, with faces chosen to hold without cutting the fabric | Wedge, vice-action, pneumatic and hydraulic grips, built to the specimen |
| Environment | 21 ± 1 °C and 65 ± 2 % RH — the textile standard atmosphere | 3009 series chambers, −150 °C to +400 °C — temperature only |
This page describes the method as practised. The governing text is the current edition from the issuing body. Tell us what you are testing and we will answer with the machine, the fixture and a quotation.