sjohnstone,
Creo Simulate is based on the p-version of the finite element method, in which the fidelity of the finite element model is increased by raising the polynomial orders of the finite element basis functions. This approach is in contrast to traditional h-version finite element programs, in which the fidelity of the model is increased by adding additional elements. Also, Creo Simulate has convergence algorithms that automatically increase the polynomial orders so that accurate solutions are efficiently found without requiring manual intervention from the user. The efficacy of this approach is the reason why the same result was obtained for the two PTC problems attached. I've attached two Word documents to clarify these methods and to compare results with an h-element solver. Please look at the document where three different FEA programs were used, ANSYS, StressCheck and Mechanica (now Creo Simulate).
