To perform a similar type of viscoelastic analysis, consider the following hints and recommendations:
Save the thermal analysis results (OUTRES) at required time steps so that the temperatures can be read in for the structural analysis.
Specify the correct path for the thermal analysis results (.rth file) during the structural analysis (LDREAD).
The sum of the fictive-temperature relaxation coefficients (specified in the table data activated via the TB,SHIFT,,,,FICT command) should be 1.0.
For more information, see Viscoelasticity in the Material Reference and Shift Functions in the Mechanical APDL Theory Reference.