Estimate the exact maximum stress in example 9.7 using the last three data. Compare the convergence rate and estimated exact stress with those of example 9.7.

Data From Example 9.7:

Calculating the maximum stress in a finite element model, we used a \(3 \times 2,6 \times 4,12 \times 8\), and \(24 \times 16\) elements. The results are given in the table. Estimate the exact maximum stress. For convenience, you can assume that the largest element size \(h_{1}\) is 1 .

Mesh size Max. stress (MPa) 32 71.53 6x4 75.63 12 x 8 77.35 24 x 16 77.92