ISO 20932-2:2018

Overview

ISO 20932-2:2018 - Textiles - Determination of the elasticity of fabrics - Part 2: Multiaxial tests specifies laboratory test methods to measure fabric elasticity and related surface-deformation properties when a fabric is distended by a hemispherical probe. The standard defines two distinct test procedures: Method A (dynamic) and Method B (static). It applies to general fabrics (excluding narrow fabrics) and requires that the chosen method be agreed between parties and reported, since results from the two methods are not directly comparable.

Key topics and technical requirements

• Test methods:
  • Method A - Dynamic test: cycling a fabric specimen between original position and a fixed load (or distension) for repeated cycles.
  • Method B - Static test: static distension and measurement of residual deformation after recovery.
• Specimen preparation and sampling: minimum of five test specimens per laboratory sample; specimens must avoid selvedges, folds and be cut according to the patterns in the standard (Method A specimen diameter: 145 ± 2 mm).
• Conditioning: preconditioning and testing atmospheres follow ISO 139; samples conditioned in a tension-free state (minimum times specified).
• Apparatus and calibration: requirement for a constant-rate-of-extension (CRE) testing machine with metrological confirmation per ISO 10012, force-measuring accuracy class 1 per ISO 7500-1, and data acquisition at a minimum of 8 samples/second when using digital recording.
• Operating parameters (examples in the standard): distension rates such as 200 mm/min for woven/nonwoven and 500 mm/min for knitted fabrics; typical cycling forces (e.g., 10 N, 50 N, 100 N) used as agreed between parties.
• Results and reporting: detailed expressions, calculations, and the requirement that the chosen method be stated in the test report.

Practical applications and users

ISO 20932-2 is intended for:

• Textile laboratories performing fabric elasticity measurement and multiaxial deformation testing.
• Product developers and textile engineers evaluating performance of upholstery, apparel, technical textiles and nonwovens under multidirectional loading.
• Quality control teams needing reproducible methods to quantify residual deformation (bagging), maximum deformation, and modulus for comparative assessment within the same test method.

Benefits:

• Provides reproducible multiaxial test procedures to inform material selection, product design and durability assessments.
• Enables standardized reporting for supplier–buyer agreements when method choice is specified.

Related standards

• ISO 20932-1 - Strip tests for fabric elasticity (part of the same series)
• ISO 139 - Standard atmospheres for conditioning and testing
• ISO 7500-1 and ISO 10012 - Requirements for force measurement accuracy and measurement management systems

Keywords: ISO 20932-2, elasticity of fabrics, multiaxial tests, textile testing, dynamic and static methods, CRE testing machine, fabric elasticity measurement.