I am running a pipeline tie-in spool model with various expansions etc applied to the model. I initially had 4 loadcases, operating conditions with waves from 4 directions. I then added 8 more loadcases to assess two different potential pipeline expansion values (again for 4 different wave directions) giving me 12 loadcases. When I run the first four loadcases on their own the stresses are within allowable limits, however when I run all twelve I get a failure in the first four loadcases. Can anyone advise what may be occurring here? Thanks