BS ISO 27727:2008 Rubber, vulcanized. Measurement of fatigue crack growth rate
BS ISO 27727 specifies a method for the determination of the fatigue crack growth rate of vulcanized rubber under repeated loading over an extended period of time. The crack starts from the tip of a cut made in the test piece before the test, and grows progressively until it finally becomes large enough for complete fracture to occur.
Using a pure-shear test piece, measurements are made to monitor the crack growth under the cyclic loading in order to obtain the crack growth rate, i.e. the increase in crack length per cycle. Tests are carried out at various tearing energies by varying the strain energy density in the test piece.
This is done by changing the strain amplitude.
Contents of BS ISO 27727:
Foreword
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Apparatus
5.1 Fatigue crack growth rate test machine
5.2 Image-processing device
5.3 Temperature-controlled chamber
5.4 Thickness- and width-measurement instruments
6 Test pieces
6.1 Dimensions
6.2 Number of test pieces
6.3 Time interval between moulding and testing
6.4 Conditioning
6.5 Preparation of test pieces for testing
7 Test conditions
7.1 Temperature
7.2 Cycle frequency
7.3 Strain amplitude
7.4 Testing under non-relaxed conditions
8 Procedure
8.1 Determination of strain energy density
8.2 Determination of tearing energy
8.3 Measurement of crack growth
9 Expression of results
10 Precision
11 Test report
Bibliography
ISO 27727:2008