BS EN ISO 8256:2004

Foreword
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Apparatus
   5.1 Test machine
   5.2 Pendulum and striker
   5.3 Crosshead
   5.4 Clamping devices/jaws
   5.5 Micrometers and gauges
6 Test specimens
   6.1 Shape and dimensions
   6.2 Preparation
   6.3 Notching of specimens
   6.4 Number of test specimens
   6.5 Anisotropy
   6.6 Conditioning
7 Procedure
8 Determination of energy corrections
   8.1 Method A - Correction E[q] due to the plastic
       deformation and the kinetic energy of the
       crosshead
   8.2 Method B - Crosshead-bounce energy E[b]
9 Calculation and expression of results
   9.1 Calculation of corrected tensile-impact energy
   9.2 Calculation of tensile-impact strength
   9.3 Statistical parameters
   9.4 Number of significant figures
10 Precision
11 Test report
Annex A (normative) Determination of correction factor
                    for method A
Annex B (normative) Determination of bounce-correction
                    factor for method B
Bibliography

Provides two methods (method A and method B) for the determination of the tensile-impact strength of plastics under defined conditions. These methods are applicable both to specimens prepared from moulding materials and to specimens taken from finished or semi-finished products (for example mouldings, films, laminates, or extruded or cast sheets).

1.1 This International Standard specifies two methods (method A and method B) for the determination of the tensile-impact strength of plastics under defined conditions. The tests can be described as tensile tests at relatively high strain rates. These methods can be used for rigid materials (as defined in ISO472), but are especially useful for materials too flexible or too thin to be tested with impact tests conforming to ISO179 or ISO180.

1.2 These methods are used for investigating the behaviour of specified specimens under specified impact velocities, and for estimating the brittleness or the toughness of specimens within the limitations inherent in the test conditions.

1.3 These methods are applicable both to specimens prepared from moulding materials and to specimens taken from finished or semi-finished products (for example mouldings, laminates, or extruded or cast sheets).

1.4 Results obtained by testing moulded specimens of different dimensions may not necessarily be the same. Equally, specimens cut from moulded products may not give the same results as specimens of the same dimensions moulded directly from the material. Test results obtained from specimens prepared from moulding compounds cannot be applied directly to mouldings of any given shape, because values may depend on the design of the moulding and the moulding conditions. Results obtained by method A and method B may or may not be comparable.

1.5 These methods are not suitable for use as a source of data for design calculations on components. Information on the typical behaviour of a material can be obtained, however, by testing different types of test specimen prepared under different conditions, and by testing at different temperatures. The two different methods are suitable for production control as well as for quality control.