Crack growth in a rubber material can be detrimental to the performance of the end product. Flexing, punctures, or tearing in service can worsen the issue even in materials that are extremely resistant to cracking.
Crack growth testing—also referred to as crack propagation, DeMattia flexing, MRPRA, and Ross flex—indicates how resistant a rubber material is to cracking while flexing. When looking at synthetic compounds (i.e. SBR type), it’s also important to better understand the effect of cuts or tears that could occur while in service.
In order to evaluate the additional variable of puncturing or tearing the material, the compound is pierced with a standardized tool in order to create a cut or tear of a specific size. The material is then flexed in order to measure crack growth in the material over a given period of time.
- ASTM D813— Standard Test Method for Rubber Deterioration—Crack Growth
- ASTM D1052— Standard Test Method for Measuring Rubber Deterioration—Cut Growth Using Ross Flexing Apparatus