Heitmann method

In: local elastic-plastic strain methods->uniaxial methods

This method is referenced in [NHB86]. It is based on the total strain energy and includes the effect of potential energy.

The mean stress effect is modelled on the basis of the crack closure concept. Note that the values of R > 3 (cases of the whole cycle being in the compressive mode) generate error in the calculation of the equivalent stress range. The user is warned about this fact and the appropriate damage for such cycle is set to zero.

The conversion to an equivalent value allows a use of the common uniaxial rain-flow decomposition. The choice of the appropriate decomposition method is the point in Calculation Methods window, where the way of the tensor's reduction is chosen.

The exponent n' of the Ramberg-Osgood curve is replaced by the ratio b/c - this material parameter is not required by PragTic.

Note: Would not the crack closure concept was mentioned in [NHB86], I would try to replace the original R by R of fully reversed cycle R=-1. Because of I have not found any further reference describing the use of this this method, I have not tried anything else.

Nomenclature:

Decomposition

- Rain-flow with von Mises reduction

- Rain-flow with Tresca reduction

- Rain-flow with von Mises (signed) reduction

Elasto-plasticity

- No

- Neuber elastic-plastic accommodation

- Glinka elastic-plastic accommodation

Material parameters

© PragTic, 2007

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