Length: 240 mm;
Width: 180 mm;
Radius of central opening: 30 mm;
Thickness: 5 mm.

Due to mirror symmetry one quarter of the structure is presented, and internal boundaries are restrained
in X and Y directions respectively.

Given: Young's modulus E = 207000 N/mm^{2} Poisson's ratio ν = 0.3.

The uniform tensile loading (40 N/mm^{2}) is applied to the bottom edge of the structure.

Problem: Determine the concentration factor due to presence of the central opening.

Solution: The concentration factor may be obtained from the loading stress (40 N/mm^{2}) and the maximum computed stress (146 N/mm^{2}) as k = 146 / 40 = 3.65.