Model Details and Parameters
The purpose of this test case is to validate the plate/shell element solver in SkyCiv Structural 3D (S3D). The results were compared against a third-party analysis software. In this test case the following model parameters were used:
- Analysis Type: Linear Static
- Material: Structural Steel
- Young’s Modulus: 200,000 MPa
- Poisson’s Ratio: 0.27
- Plate Type: Mindlin Plane Stress
- Plate Size: 2m x 1m
- Plate Thickness: 10 mm
- Corner Supports: FFFRRR (3D Pin)
- Pressure Load: 1 kPa normal to plate

Results – 8×4 Structured Mesh
| Result | Location | SkyCiv | Third-Party 1 | Difference 1 | Third-Party 2 | Difference 2 |
| Max Displacement Z (mm) | Node 8 (center of longer edge) | -13.004 | -13.111 | -0.82% | -13.004 | 0.00% |
| Max Von Mises Stress – Element (MPa) | Element 28 Top | 28.687 | 28.834 | -0.51% | 28.687 | 0.00% |
| Reaction Z (kN) | Node 1 | 0.500 | 0.500 | 0.00% | 0.500 | 0.00% |
| Max Moment X – Element (kN-m/m) | Element 24 | 0.167 | 0.167 | 0.00% | 0.167 | 0.00% |
Results – 16×8 Structured Mesh
| Result | Location | SkyCiv | Third-Party 1 | Difference 1 | Third-Party 2 | Difference 2 |
| Max Displacement Z (mm) | Node 12 (center of longer edge) | -13.171 | -13.220 | -0.37% | -13.171 | 0.00% |
| Max Von Mises Stress – Element (MPa) | Element 120 Top | 30.087 | 30.129 | -0.14% | 30.087 | 0.00% |
| Reaction Z (kN) | Node 1 | 0.500 | 0.500 | 0.00% | 0.500 | 0.00% |
| Max Moment Y – Element (kN-m/m) | Element 120 | 0.510 | 0.510 | 0.00% | 0.510 | 0.00% |
Results – Unstructured Mesh
| Result | Location | SkyCiv | Third-Party 1 | Difference 1 | Third-Party 2 | Difference 2 |
| Max Displacement Z (mm) | Node 14 (center of longer edge) | -13.20518 | -13.23577 | -0.23% | -13.20589 | -0.01% |
| Max Von Mises Stress – Element (MPa) | Element 99 Top | 30.48232 | 28.78667 | 5.89% | 30.33762 | 0.48% |
| Reaction Z (kN) | Node 1 | 0.50002 | 0.50000 | 0.00% | 0.50000 | 0.00% |
| Min Moment XY – Element (kN-m/m) | Element 198 | -0.19865 | -0.19126 | 3.86% | -0.20028 | -0.81% |

Extra Considerations
- This verification model was created and checked on 28 February 2020. Since this date, the plate solver and S3D software may have been further improved to achieved greater accuracy.
- Plates are not exact elements like beam and frame elements and therefore the mesh plays a huge role in the results. Always try to use a structured mesh when it is possible to do so.
- Results between software will never be exactly the same since different elements are used and the nature of plates are approximate

