Keyword type: step
This option is used to define an increase of initial strains. The values are added to the initial strains already present in the model. The use of this option requires the previous use of *INITIAL CONDITIONS, TYPE=PLASTIC STRAIN or *MODEL CHANGE, TYPE=ELEMENT, ADD or *MODEL CHANGE, TYPE=ELEMENT, ADD=STRAIN FREE.
The resulting initial strain components are subtracted from the strain components computed from the displacement field. If thermal strains are relevant they are additionally subtracted. The resulting strain is used to compute the stress and tangent stiffness matrix using the appropriate constitutive equations.
Please note that the strains have to be provided in the GLOBAL (rectangular) coordinate system, no matter whether an *ORIENTATION card or *TRANSFORM card applies to the corresponding element.
Examples: *INITIAL STRAIN INCREASE 20,5,0.01,0.,0.01,0.,0.,0.
increases the initial strain at integration point 5 of element 20 by a normal global x and normal global z component of 0.01, the other strains remain unchanged.
Example files: inistrain2.