A modified cyclic crack propagation description

• A multiplicative crack propagation law is proposed including R-effects.
• The Walker law was extended to take HCF-cycles into account.
• More than 1000 tests were evaluated to check the new law.
• The law was applied to steel, Nickel and Titanium alloys.

A new form of the crack propagation law is presented for cyclic crack propagation calculations. It is characterized by a multiplicative juxtaposition of the Paris range, the threshold and critical limit and the R-dependence. The latter is covered by a modified Walker approach, in which the influence of small cycles at high R-ratios is appropriately adjusted. The concrete form of the R-dependence was validated by application to a wide range of materials.