fatigue crack growth testing instrument

Fatigue crack growth testing module

Resistance to fatigue, ageing and crack growth are major issues for rubber like materials.

Current commercial methods for crack growth testing have been restricted to time to failure test. 

Since 1999, cooperation with leaders of the Tire industry led Metravib to propose various customized testing machines dedicated to crack growth testing. 

Based on this extensive experience, Metravib developed a Fatigue Crack Growth Testing Module to bring to rubber industry and research a quantitative and productive advanced testing instrument.


Fatigue crack growth assets

Fatigue crack growth testing module is a smart add-on dedicated to the Metravib DMA+ series.

Taking advantage of the DMA+series advanced performances, it extends dramatically their testing capabilities in combining DMA, fatigue and crack growth testing in one single instrument.

The test is performed on a pure shear specimen featuring 40, 60 or 80mm width.

The specimen is preferably molded and designed with beads, then clamped into stainless steel jaws.
Rubber strips can be as well tested by using dedicated jaws.

A CCD video camera is used to record periodic photos of the crack and to determine accurately the crack tip position.

The motorized video camera makes possible to scan the entire width of the specimen, and to follow up to 4 cracks in one single experiment with an extended unmatched accuracy inferior to +/- 2µm.

The crack growth test may be performed automatically without operator’s intervention and ends automatically according to various predefined criterions (cycles numbers, crack growth rate stabilization, crack deviation, crack max length, …).

crack growth rate measurement

Fatigue crack growth main specifications

  • Specimen width: 40, 60, 80 mm
  • Specimen height: 6 mm (advised between beads)
  • Specimen type: strip or molded with beads
  • Number of cracks: up to 4
  • Crack length resolution: better than 2 μm
  • Conditioning temperature: 0°C to 300°C
  • Frequency: 1Hz to 200Hz (main) / 1kHz (harmonics)