Creep: Theta Projection Creep

Description

Defines creep data parameters according to the theta projection creep law.

The theta-projection concept provides an alternative approach for describing the uniaxial creep response that implies any secondary region is simply an inflection on the curve where the strain hardening (primary) effects are balanced by strain softening (tertiary) processes.

Toolbar Functions

See LAYOUTS: Creep.

COEFFICIENTS

A_i are material constants.

B_i are material constants.

C_i are material constants.

D_i are material constants.

i = 1, ... , 4

PARAMETERS

Time Unit (t)

The unit of time in which the coefficients are specified.

Hardening

The creep hardening rule determines whether the creep strain rate is a function of the elapsed time or the amount of creep strain.

See Metal Creep: Hardening.

Time

With this rule, the creep strain rate is calculated based on the elapsed time.
Strain

With this rule, the creep strain rate is calculated based on the amount of creep strain in the model. Experimental evidence suggests that the strain hardening rule is to be favoured over the time hardening rule.

If Cyclic is set, extra auxiliary rules are used in conjunction with the strain hardening rule in order to better model stress reversal situations. Such modified strain hardening rule should be used for cyclic loading situations only.

Temperature

Not applicable to this creep law.