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