EN ISO 20337:2019 PDF

Overview

EN ISO 20337:2019 (identical to ISO 20337:2018) specifies a shear test method using a shear frame to determine the in‑plane shear stress / shear strain response, shear modulus and shear strength of fibre‑reinforced plastic composites. Published by CEN and adopted in 2019, the standard applies to continuous‑fibre laminates (thermoset and thermoplastic), unidirectional layers, fabrics and short/long fibre‑reinforced plastics with fibre orientations of 0° and 0°/90°, provided the lay‑up is symmetrical and balanced about the specimen mid‑plane.

Key topics and requirements

• Test principle: Uses a shear frame fixture to impose a near‑pure shear field across the specimen free area; specimen edges are uniformly clamped to avoid fibre rotation and load redistribution.
• Measured outputs: In‑plane shear stress–shear strain curve, in‑plane shear modulus (G12) and in‑plane shear strength (τ12M), including nonlinear behaviour at strains greater than 5%.
• Applicability: Thermoset/thermoplastic matrix laminates, unidirectional and fabric reinforcements, and short/long fibre composites with 0° or 0°/90° fibre orientations.
• Apparatus & instrumentation: Tensile test machine, shear frame fixture, strain measurement system, micrometer for thickness - plus calibration and verification requirements for force measurement.
• Specimen preparation & conditioning: Specifies specimen shape, inspection, number of specimens and conditioning (references ISO 291 for atmospheres). Normative references include ISO 1268, ISO 2818, ISO 2602, ISO 7500‑1 and ISO 12781‑1.
• Data handling: Procedures for test speed, data collection, failure mode identification, calculations and test reporting.

Practical applications and users

Who uses EN ISO 20337:2019:

• Composite material manufacturers and suppliers validating shear performance.