NF EN ISO 178

<p>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.</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> <ul> <li>thermoplastic moulding, extrusion and casting materials, including filled and reinforced compounds in addition to unfilled types; rigid thermoplastics sheets;</li> <li>thermosetting moulding materials, including filled and reinforced compounds; thermosetting sheets.</li> </ul> <p>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.</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 and/or ISO 1209‑2 can be used.</p> <p>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.</p>