ASTM D885
Tire Cord and Yarn Grip

Standard Test Methods for Tire Cords, Tire Cord Fabrics, and Industrial Filament Yarns Made from Manufactured Organic-Base Fibers - PDF

ASTM D885 specifies the test methods for measuring the tensile properties of tire cords, tire cord fabrics, and industrial filament yarns made from man-made, organic-base fibers such as polyester, nylon, aramid, and rayon.
These materials are critical for reinforcing tires, belts, hoses, and other industrial products requiring strength, flexibility, and durability.

The standard ensures consistent evaluation of breaking strength, elongation, modulus, and other key mechanical properties.

Purpose of ASTM D885

The main objectives of ASTM D885 testing are to:

• Determine breaking strength and elongation at break.

• Measure tensile modulus (initial slope of stress-strain curve).

• Evaluate force at specified elongations (e.g., 2%, 5%, 10%).

• Support quality assurance and lot-to-lot consistency for reinforcement materials.

• Provide comparable data for engineering design, especially in high-stress applications like tires and industrial belting.

Equipment Required for ASTM D885 Testing

The following equipment is needed to perform ASTM D885 testing properly:

• Universal Testing Machine (UTM):

  • Capable of applying tensile forces with controlled rates of loading and high-resolution data acquisition.

  • Load cells appropriate to the strength of the cords or fabrics being tested (ranging from a few hundred Newtons to tens of kilonewtons).

• Specialized Grips for Tire Cords and Fabrics:

  • Pneumatic bollard grips and fabric grips with serrated or rubberized faces to prevent slippage without damaging the specimen.

  • Capstan grips may be used for very high-strength yarns or cords.

• Specimen Cutting Tools:

  • Templated cutting dies to ensure standardized sample widths and lengths.

  • Hot knives may be used to seal synthetic fiber edges to prevent fraying.

• Environmental Chamber (Optional but Recommended):

  • To condition samples at specific temperature and humidity levels before and/or during testing.

• Extensometers (Optional):

  • Used for highly accurate strain measurements, especially when calculating modulus or stress-strain behavior.

Specimens

Specimens may include:

• Single cords or yarns extracted from fabric.

• Cord-reinforced fabrics cut to a specified size (typically with cords aligned longitudinally).

• Industrial filament yarns prepared with specified twist and tension.

Specimens should be conditioned in the standard laboratory atmosphere for textiles (typically 21°C and 65% relative humidity) for at least 24 hours before testing unless otherwise noted.

General Test Procedure for ASTM D885

1. Preparation:

   • Condition specimens if required.

   • Measure and record initial specimen dimensions (length, width, cross-sectional area).

2. Mounting:

   • Install the specimen into the grips carefully to avoid introducing stress concentrations or slippage.

   • Apply a light preload if necessary to eliminate slack.

3. Testing:

   • Stretch the specimen at a constant rate of extension or load (commonly specified in the procedure depending on material type).

   • Continue applying tensile force until the specimen ruptures.

4. Data Collection:

   • Record maximum force (breaking strength).

   • Record elongation at break (strain).

   • Determine tensile modulus (initial slope of the load-elongation or stress-strain curve).

   • Measure force at specific elongations if required.

Results and Reporting

A full ASTM D885 test report typically includes:

• Material identification (fiber type, construction, manufacturer, batch).

• Breaking strength (force or stress).

• Elongation at break (%).

• Modulus at specified strain levels (optional).

• Force values at specified elongations (2%, 5%, etc.).

• Type of failure observed (e.g., rupture at mid-span, slippage in grip).

• Number of specimens tested and any deviations from standard procedure.

• Test rate, temperature, humidity, and grip type.

Related ASTM and Similar Testing Standards

Several related standards are useful for similar or supporting tensile testing of yarns, cords, and fabrics:

• ASTM D7269 – Standard Test Methods for Tensile Testing of Aramid Yarns:
  Focused on tensile testing of aramid yarns specifically, similar to tire cord testing but limited to yarn stage.

• ASTM D2256 – Standard Test Method for Tensile Properties of Yarns by the Single-Strand Method:
  General tensile testing for textile yarns across different fiber types.

• ASTM D6775 – Standard Test Method for Breaking Strength and Elongation of Textile Webbing, Tape, and Braided Material:
  Applies to wider materials like seat belts, industrial tapes, and straps.

• ASTM D3936 – Standard Test Method for Resistance to Delamination of Secondary Backings of Pile Yarn Floor Coverings:
  Related to bond strength testing for fabrics but more specialized.

• ISO 3341 – Textile glass – Yarns – Determination of breaking force and breaking elongation:
  An international equivalent often referenced for filament yarns made from glass but conceptually similar for other high-performance fibers.

Applications of ASTM D885 Testing

Industries relying on ASTM D885 include:

• Tire Manufacturing: Cord and belt reinforcement layers in tires.

• Automotive: Drive belts, timing belts, hoses.

• Aerospace: Reinforced flexible composite materials.

• Industrial Products: Conveyor belts, lifting slings, safety equipment.

Accurate tensile property data ensures the structural integrity, performance, and safety of the final product, especially in dynamic and high-load environments.

Conclusion

ASTM D885 provides a comprehensive framework for tensile testing of tire cords, cord fabrics, and industrial filament yarns.
It supports consistent quality control, material specification, and engineering design across industries that demand high performance and reliability from textile-reinforced structures.