Paper Title
Investigations On Mesh Discretization Error In Fem Based Structural Analysis Using Ansys

The current investigation focuses on error inherent in the FE model and mesh discretization error which creeps into the FE solution as a result of the interpolation of the field derivative values at the nodes. The error in stress at each node is integrated over the entire volume of the element and the error so calculated is energy error for the element. The corresponding error in energy norm reduces as we go on increasing the mesh density in the region having high stress concentration. Mesh convergence study was conducted on different features and loading conditions encountered in a typical commercial aircraft engine with increasing order of complexity. Accordingly simple model 3D turbine Disk rim is considered for the above studies. FE analysis considering multiple iterations by gradually increasing the mesh size was performed on each of the above models and the results were analyzed for observing a trend in the convergence along with the associated error in the solution. The effect of varying geometry was also studied. Results showed that the energy error norm was consistent with the peak stress values and was found to within certain percentage band for the typical features considered for our case studies. Thus shows that the methodology adopted helps in understanding the behavior of energy error corresponding to the peak stress values and the energy error norm can be incorporated as a criterion to test the convergence of the solution. Based on all the case studies carried out it was found that the normalized percentage error in energy was found to be within 6% to 8% for the converged solution.