大家好我是剛開始學(xué)習(xí)ansys的小白，遇到了這個(gè)問(wèn)題該怎么解決呢？Preconditioned conjugate gradient solver error level 1.  Please check  for an insufficiently constrained model.  Switching to the sparse         direct solver may allow this nonlinear analysis to continue beyond  this point.