The SWR software uses an automated system to determine the number of terms in the Legendre polynomial series that are needed to achieve a desired solution accuracy. The solution is computed with an initial number of terms in each direction (x and y). At each iteration, two addtional terms are added to the solution. The terms are distributed between x and y based on an heuristic formula that considers the plate aspect ratio. The solution is then recomputed. If the relative difference in results between the solutions is less than a specified tolerance, then the second solution is returned. If not, two additional terms are added.
The system requires less than a 1% change for the pressure solution, or a 2% change for buckling or vibration.