OS-E: 0130 Plate with Central Hole using NLOUT

A uniform, homogeneous plate which is symmetric about horizontal axes in both geometry and loading, to find the maximum axial stress in the plate with a hole.

This means that the state of stress and deformation below a horizontal centerline is a mirror image of that above the centerline, and likewise for a vertical centerline. You can take advantage of the symmetry and, by applying the correct boundary conditions, use only a quarter of the plate for the finite element model to test for non-convergence solution results in OptiStruct.
Figure 1. FE Model

Model Files

Before you begin, copy the file(s) used in this example to your working directory.

Model Description

Place the origin of X-Y coordinates at the center of the hole. If you pull on both ends of the plate, points on the centerlines will move along the centerlines but not perpendicular to them. This indicates the appropriate displacement conditions to use, as shown in Figure 1.
FE Model
Element Types
The linear material properties are:
MAT1 and MATS1
Young’s Modulus
1.5E5 MPa
Poisson's Ratio
Initial Yield Point
60.5 MPa


Nonlinear iterations do not converge and OptiStruct saves the last converged solution by default with NLOUT.

To save non-converged solution, NLOUT is specified in the model. The SVNONCNV parameter on NLOUT entry is set to YES by default:
Saves the last non-converged iteration
In H3D, it is labeled as NON-CONVERGENT at the final load factor, shown in Figure 2.
Figure 2. Stress Contour