NF EN ISO 178

NF EN ISO 178

February 2011
Standard Cancelled

Plastics - Determination of flexural properties

ISO 178:2010 specifies a method for determining the flexural properties of rigid and semi-rigid plastics under defined conditions. A standard test specimen is defined, but parameters are included for alternative specimen sizes for use where appropriate. A range of test speeds is included. The method is used to investigate the flexural behaviour of the test specimens and to determine the flexural strength, flexural modulus and other aspects of the flexural stress/strain relationship under the conditions defined. It applies to a freely supported beam, loaded at midspan (three-point loading test). The method is suitable for use with the following range of materials: thermoplastic moulding, extrusion and casting materials, including filled and reinforced compounds in addition to unfilled types; rigid thermoplastics sheets; thermosetting moulding materials, including filled and reinforced compounds; thermosetting sheets. ISO 178:2010 applies to fibre-reinforced compounds with fibre lengths less than or equal to 7,5 mm prior to processing. For long-fibre-reinforced materials (laminates) with fibre lengths greater than 7,5 mm, see ISO 14125. The method is not normally suitable for use with rigid cellular materials or sandwich structures containing cellular material. In such cases, ISO 1209‑1 and/or ISO 1209‑2 can be used. Contrary to the previous editions of this International Standard, this edition specifies two methods, method A and method B. Method A is identical to the method in previous editions of this International Standard, i.e. it uses a strain rate of 1 %/min throughout the test. Method B uses two different strain rates: 1 %/min for the determination of the flexural modulus and 5 %/min or 50 %/min, depending on the ductility of the material, for the determination of the remainder of the flexural stress-strain curve.

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Main informations

Collections

National standards and national normative documents

Publication date

February 2011

Number of pages

26 p.

Reference

NF EN ISO 178

ICS Codes

83.080.01   Plastics in general

Classification index

T51-001

Print number

1 - 03/02/2011

International kinship

European kinship

EN ISO 178:2010
Sumary
Plastics - Determination of flexural properties

ISO 178:2010 specifies a method for determining the flexural properties of rigid and semi-rigid plastics under defined conditions. A standard test specimen is defined, but parameters are included for alternative specimen sizes for use where appropriate. A range of test speeds is included.

The method is used to investigate the flexural behaviour of the test specimens and to determine the flexural strength, flexural modulus and other aspects of the flexural stress/strain relationship under the conditions defined. It applies to a freely supported beam, loaded at midspan (three-point loading test).

The method is suitable for use with the following range of materials:

  • thermoplastic moulding, extrusion and casting materials, including filled and reinforced compounds in addition to unfilled types; rigid thermoplastics sheets;
  • thermosetting moulding materials, including filled and reinforced compounds; thermosetting sheets.

ISO 178:2010 applies to fibre-reinforced compounds with fibre lengths less than or equal to 7,5 mm prior to processing. For long-fibre-reinforced materials (laminates) with fibre lengths greater than 7,5 mm, see ISO 14125.

The method is not normally suitable for use with rigid cellular materials or sandwich structures containing cellular material. In such cases, ISO 1209‑1 and/or ISO 1209‑2 can be used.

Contrary to the previous editions of this International Standard, this edition specifies two methods, method A and method B. Method A is identical to the method in previous editions of this International Standard, i.e. it uses a strain rate of 1 %/min throughout the test. Method B uses two different strain rates: 1 %/min for the determination of the flexural modulus and 5 %/min or 50 %/min, depending on the ductility of the material, for the determination of the remainder of the flexural stress-strain curve.

Replaced standards (2)
NF EN ISO 178
May 2003
Standard Cancelled
Plastics - Determination of flexural properties

Le présent document décrit une méthode pour déterminer des propriétés en flexion des plastiques rigides (voir 3.12) et semi-rigides dans des conditions définies.

NF EN ISO 178/A1
July 2005
Standard Cancelled
Plastics - Determination of flexural properties - Amendment 1 : precision statement

Le présent amendement précise la fidélité de la détermination de propriétés de flexion.

Standard replaced by (1)
NF EN ISO 178
May 2019
Standard Current
Plastics - Determination of flexural properties

<p>This document specifies a method for determining the flexural properties of rigid and semi-rigid plastics under defined conditions. A preferred test specimen is defined, but parameters are included for alternative specimen sizes for use where appropriate. A range of test speeds is included.</p> <p>The method is used to investigate the flexural behaviour of the test specimens and to determine the flexural strength, flexural modulus and other aspects of the flexural stress/strain relationship under the conditions defined. It applies to a freely supported beam, loaded at midspan (three-point loading test).</p> <p>The method is suitable for use with the following range of materials:</p> <p>— thermoplastic moulding, extrusion and casting materials, including filled and reinforced compounds in addition to unfilled types; rigid thermoplastics sheets;</p> <p>— thermosetting moulding materials, including filled and reinforced compounds; thermosetting sheets.</p> <p>In agreement with ISO 10350-1[5] and ISO 10350-2[6], this document applies to fibre-reinforced compounds with fibre lengths ≤7,5 mm prior to processing. For long-fibre-reinforced materials (laminates) with fibre lengths &gt;7,5 mm, see ISO 14125[7].</p> <p>The method is not normally suitable for use with rigid cellular materials or sandwich structures containing cellular material. In such cases, ISO 1209-1[3] and/or ISO 1209-2[4] can be used.</p> <p>NOTE 1 For certain types of textile-fibre-reinforced plastic, a four-point bending test is used. This is described in ISO 14125.</p> <p>The method is performed using specimens which can be either moulded to the specified dimensions, machined from the central section of a standard multipurpose test specimen (see ISO 20753) or machined from finished or semi-finished products, such as mouldings, laminates, or extruded or cast sheet.</p> <p>The method specifies the preferred dimensions for the test specimen. Tests which are carried out on specimens of different dimensions, or on specimens which are prepared under different conditions, can produce results which are not comparable. Other factors, such as the test speed and the conditioning of the specimens, can also influence the results.</p> <p>NOTE 2 Especially for injection moulded semi-crystalline polymers, the thickness of the oriented skin layer, which is dependent on the moulding conditions, also affects the flexural properties.</p> <p>The method is not suitable for the determination of design parameters but can be used in materials testing and as a quality control test.</p>

Table of contents
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  • Avant-propos
    iv
  • 1 Domaine d'application
    1
  • 2 Références normatives
    2
  • 3 Termes et définitions
    3
  • 4 Principe
    5
  • 5 Machine d'essai
    5
  • 5.1 Généralités
    5
  • 5.2 Vitesse d'essai
    5
  • 5.3 Supports et poinçon de charge
    6
  • 5.4 Indicateurs de charge et de flèche
    6
  • 5.5 Dispositifs de mesurage de la largeur et de l'épaisseur des éprouvettes
    8
  • 6 Éprouvettes
    8
  • 6.1 Forme et dimensions
    8
  • 6.2 Matériaux anisotropes
    9
  • 6.3 Préparation des éprouvettes
    10
  • 6.4 Contrôle des éprouvettes
    11
  • 6.5 Nombre d'éprouvettes
    11
  • 7 Atmosphère de conditionnement et d'essai
    11
  • 8 Mode opératoire
    11
  • 9 Calcul et expression des résultats
    14
  • 9.1 Contrainte en flexion
    14
  • 9.2 Déformation en flexion
    15
  • 9.3 Module en flexion
    15
  • 9.4 Paramètres statistiques
    16
  • 9.5 Chiffres significatifs
    16
  • 10 Fidélité
    16
  • 11 Rapport d'essai
    16
  • Annexe A (informative) Déclaration de fidélité
    17
  • Annexe B (informative) Influence d'un changement de la vitesse d'essai sur les valeurs mesurées des propriétés en flexion
    19
  • Bibliographie
    20
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