history_hsv-manager_LS-Dyna

A manager for LS-Dyna Fortran to store and retrieve data easily in the list of history variables hsv.

This enables you to centrally organise which history variable is stored at which location and easily reorganise your history. For instance, if you want to retrieve your damage variable in the user-material from the history, you usually write damage_n = hsv(9), if the damage is stored at the 9th entry of the list of history variables hsv. Now imagine, you clean or extend your material model and now the damage should be stored in position 8. You would need to go through every line of code, where you retrieve or save the damage into hsv(9) and change this. Sounds error-prone, like a waste of time and very cumbersome. With this hsv-manager you just write damage_n = hsv_get_scalar('damage', hsv) to retrieve the damage and call hsv_set_scaler(damage_n,'damage',hsv) to store the damage back into hsv and only in a single central (!) place change the ordering of your history variables.

If you now wonder about efficiency. Of course it is faster to use for instance hsv(9) and calling the hsv-manager. Regard the hsv-manager as a good tool for code development. Once your material model is perfect/verified/validated/tested, it is very easy to replace the hsv-manager calls by 'hsv(9)' etc. to get the last millisecond in efficiency. (Just note that a code is never perfect, always requires support/debugging/bug fixes/extensions/changes/optimisations/etc.)

Usage and setup

Open the file 'hsv_get_sth.F' and change the names, indices and lengths of the variables you want to store in the history list 'hsv'. As shown, you can introduce multiple hsv-variants. For instance, if one of your material models only considers plasticity, you do not have to store the damage variable and related values. This simply saves memory.

Set

To set a value call the according subroutine

  call hsv_set_X(X,'X',hsv) ! put the value of X as 'X' into the history

Currently, you need to specify hsv_set_X as hsv_set_scalar or hsv_set_symTen2 etc., so that the hsv-manager knows what and how to save it. For instance, a second order tensor (3x3 entries) can be reduced to 6 independent components if it is defined as symmetric.

GET

To get a value from the history call the function

  X = hsv_get_X('X', hsv) ! get me the value of 'X' from the history

hsv_get_X needs to be again specified as _scalar or _symTen2, etc.

INIT

To use the different hsv-variants, you need to initialise the hsv. This must be done before any value can be extracted or saved into hsv. For this call,

  call hsv_init(hsv, cm_all)

Here, cm_all is a bit special (see cm-maanager), but basically you store the hsv-variant (1,2,3,...) into the first entry of hsv, so e. g. hsv(1)=3 to use the third hsv-variant.

Example

@todo automatically detect the data type of the input argument

@todo add an example on the usage to get and set e.g. the hardening variable for elasto-plasticity