1. A computer implemented and user assisted process for prescribing second-order tetrahedral elements during simulation for assisting in the design analysis of a structure by a user, comprising the steps of: (a) defining, by the user, a finite element model for an element of the structure including at least one tetrahedral element; (b) defining, by the user, at least one node of the at least one tetrahedral element; (c) defining, by at least one of the computer and the user, the at least one tetrahedral element as a combination of first order hexahedral sub-elements and defining at least one sub-element node of at least one of the hexahedral sub-elements using the at least one node; (d) executing, by the computer, the simulation using the combination of first order hexahedral sub-elements; (e) evaluating, by at least one of the computer and the user, and redesigning by the user the structure responsive to said executing step (d) for structural integrity.