The region around the curved portion in the model is normally the region of higher stress concentration than the other region. For this reason, it is necessary to have better understanding of the model in this region.
One method to improve the solution field in these region is mesh refinement. Mesh refinement can be increasing the number of elements or increasing the order of the existing elements.
From the geometric point of view (for curved portion) it is better to increase the number of elements as it will lead to better convergence of the solution without increasing the computational time or the problem size.
Utilizing the St Vinant's principle, only a small portion of mesh around the curved portion can be refined for reducing the error in accuracy of the solution and also save a lot of computation time otherwise needed for the entire model.