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: Quadrangle
• Plate Corner 1 Coordinates:  0, 0, 0 m
  
• Plate Corner 2 Coordinates:  1, 1, 0 m
• Plate Corner 3 Coordinates:  1, 1.5, 0 m
• Plate Corner 4 Coordinates:  0, 1, 0 m
• Plate Thickness: 5 mm
• Left-Edge Supports: FFFFFF (Fixed)
• Point Load: 1 kN +Y vertical at Plate Corner 2
  

Results – 5×5 Structured Mesh

Result	Location	SkyCiv	Third-Party 1	Difference 1	Third-Party 2	Difference 2
Min Displacement X (mm)	Node 3	-0.01557	-0.01389	12.10%	-0.01557	0.00%
Max Displacement Y (mm)	Node 3	0.01844	0.01541	19.66%	0.01844	0.00%
Max Von Mises Stress – Element (MPa)	Element 5 Top	1.68643	1.91644	-12.00%	1.67746	0.53%
Max Membrane Force XY – Element (kN/m)	Element 21	3.01272	2.70639	11.32%	2.91848	3.23%
Reaction Y	Node 15	-0.33642	-0.29053	15.80%	-0.33642	0.00%
Reaction X	Node 15	-0.63959	-0.61917	3.30%	-0.63959	0.00%

Results – 20×20 Structured Mesh

Result	Location	SkyCiv	Third-Party 1	Difference 1	Third-Party 2	Difference 2
Min Displacement X (mm)	Node 3	-0.01564	-0.01551	0.84%	-0.01564	0.00%
Max Displacement Y (mm)	Node 2	0.02020	0.02010	0.50%	0.02020	0.00%
Max Von Mises Stress – Element (MPa)	Element 20 Top	5.52230	6.42078	-13.99%	5.49870	0.43%
Max Membrane Force XY – Element (kN/m)	Element 381	5.84653	5.65927	3.31%	5.79700	0.85%

Results – Unstructured Mesh

Result	Location	SkyCiv	Third-Party 1	Difference 1	Third-Party 2	Difference 2
Min Displacement X (mm)	Node 3	-0.01556	ERR	–	-0.01556	0.00%
Max Displacement Y (mm)	Node 3	0.01982	ERR	–	0.01982	0.00%
Max Von Mises Stress – Element (MPa)	Element 82 Top	3.68514	ERR	–	3.69233	-0.19%
Max Membrane Force XY – Element (kN/m)	Element 112	5.01036	ERR	–	4.59800	8.97%

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