How do you extract strain energy from a nonlinear analysis?
You can use the following commands to extract strain energy due to nonlinear plastic strain. This same approach will also work for extracting strain energy for nonlinear creep as well. Refer to the ETABLE command and also refer to the list of element output data available as documented in your elements reference manual.
ETABLE,density,SEND,plastic ! retreive nonlinear strain energy density
ETABLE,volume,VOLU ! retrieve volume per element
SMULT,Energy,DENSITY,VOLUME,1,1 ! multiple density times volume