Standard

NS-EN ISO 178:1996

Withdrawn

Note: This standard has a new edition: NS-EN ISO 178:2019

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Abstract

1.1 This International Standard specifies a method for determining the flexural properties of 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 testing speeds is included. 1.2 The method is used to investigate the flexural behaviour of the test specimens and for determining 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). 1.3 The method is suitable for use with the following range of materials: - thermoplastics moulding and extrusion materials, including filled and reinforced compounds in addition to unfilled types; rigid thermoplastics sheets; - thermosetting moulding materials, including filled and reinforced compounds; thermosetting sheets, including laminates; - fibre-reinforced thermoset and thermoplastics composites, incorporating unidirectional or non-unidirectional reinforcements such as mat, woven fabrics, woven rovings, chopped strands, combination and hybrid reinforcements, rovings and milled fibres; sheets made from pre-impregnated materials (prepregs); - thermotropic liquid-crystal polymers. The method is not normally suitable for use with rigid cellular materials and sandwich structures containing cellular material. 1.4 The method is performed using specimens which may be either moulded to the chosen dimensions, machined from the central portion of a standard multi-purpose test specimen (see ISO 3167) or machined from finished and semi-finished products such as mouldings, laminates and extruded or cast sheet. 1.5 The method specifies 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, may produce results which are not comparable. Other factors, such as the speed of testing and the conditioning of the specimens, can also influence the results. Consequently, when comparative data are required, these factors must be carefully controlled and recorded. 1.6 Flexural properties can only be used for engineering design purposes for materials with linear stress/strain behaviour. For non-linear material behaviour the flexural properties are only nominal. The bending test should preferentially be used with brittle materials, for which tensile tests are difficult.

Document information

  • Standard from SN
  • Published:
  • Withdrawn:
  • Edition: 1
  • Version: 1
  • Document type: NAT
  • ICS 83.080
  • ICS 83.080.01
  • National Committee SN/K 138/ NS 416

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