The Free On-line Dictionary of Computing (30 December 2018):

STRUDL

   STRUctured Design Language.

   Dynamic and finite-element analysis, steel and concrete
   structures.  Subsystem of ICES.  ["ICES STRUDL-II
   Engineering User's Manual", R68-91, CE Dept MIT (Nov 1968)
   Sammet 1969, p.613].