ISO 14130:1997

Overview

ISO 14130:1997 specifies the short-beam method for measuring the apparent interlaminar shear strength of fibre-reinforced plastic composites. Intended for composites with thermoset or thermoplastic matrices, the standard defines specimen geometry, test setup, loading conditions and result calculation for screening materials and quality-control testing. It explicitly states the result is an apparent shear strength (not an absolute design parameter) and is valid only when interlaminar shear failure is obtained.

Key topics and technical requirements

• Specimen geometry
  • Standard specimen: rectangular bar, h = 2 mm, l = 20 mm, b = 10 mm (with tolerances).
  • Alternative sizing allowed using scaling rules: l = 10h and b = 5h.
• Test-fixture & machine
  • Three-point short-span flexure with loading mid-span.
  • Loading member radius: 5.0 mm ±0.2 mm; support radius: 2.0 mm ±0.2 mm.
  • Span: L = 5h ±0.3 mm (h = mean thickness).
  • Test machine and speed must meet ISO 5893; default speed 1.0 mm/min ±0.2 mm/min if not otherwise specified.
• Measurements & calculation
  • Measure width and thickness at mid-point; at least five specimens tested.
  • Apparent interlaminar shear strength tM calculated as:
    • tM = 3F / (4 b h) (F = maximum load, b = width, h = thickness)
• Failure modes
  • Acceptable: single or multiple interlaminar shear (near neutral plane).
  • Unacceptable: mixed shear/tension, pure tension/compression, plastic shear - results are not valid as interlaminar shear strength.
• Conditioning & reporting
  • Condition specimens per ISO 291 or agreed conditions.
  • Test report must include specimen details, machine accuracy (ISO 5893), loading/support radii, span, failure mode, individual and mean values, and any deviations.

Applications and users

• Useful for material screening, production quality control, and comparative evaluation of fibre-reinforced plastics.
• Typical users:
  • Composite materials engineers, R&D teams, and QA laboratories
  • Testing labs performing mechanical characterization of laminates
  • Manufacturers verifying batch-to-batch consistency
• Not recommended as a sole source for structural design values because results are size- and condition-dependent.

Related standards

• ISO 14125 - flexural properties of fibre-reinforced plastics (related three-point bending method)
• ISO 5893 - test machine requirements
• ISO 291 - conditioning atmospheres
• ISO 1268, ISO 2818 - specimen preparation
• ISO 2602 - statistical analysis of results

Keywords: ISO 14130:1997, short-beam method, apparent interlaminar shear strength, fibre-reinforced plastic composites, interlaminar shear test, test specimens, quality control.