Problem Description
In this example a twisted cantilever beam, modeled with shell elements, is subjected to unit forces at the tip in the in-plane and out-of-plane directions, that is, the Y and Z directions, respectively. The in-plane and out-of-plane loads are applied in different load cases. The tip displacements in the direction of the load are compared with independent hand calculated results.
The geometry, properties and loading are as suggested in MacNeal and Harder 1985. The cantilever beam is twisted 90° from the root (fixed end) to the tip. It is 12 inches long, 1.1 inches wide and 0.32 inches thick. For modeling in this model the twisted beam is meshed 2x12 (24 area objects total) as shown in the figure.
Tested Features
- Membrane analysis using shell elements
- Plate bending analysis using shell elements
- Joint force loading
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Object Link: https://openbrim.org/objidwtmdl47c1k9aki7m1t6t.libobj
Thin Plate Option
| Model and Mesh | Load Case and Type | Output Parameter | OpenBrIM | SAP2000 | Independent | Percent Difference (SAP2000 vs Independent) | Percent Difference (OpenBrIM vs Independent) |
|---|---|---|---|---|---|---|---|
12x2 mesh | Load case IN In-Plane | Uy, in Average of jts 13, 26, 39 | 0.003029 | 0.005415 | 0.005429 | -0.3% | -44.2% |
Load case OUT Out-of-Plane | Uz, in Average of jts 13, 26, 39 | 0.001478 | 0.001769 | 0.001749 | 1.1% | -15.5% |
Thick Plate Option
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Percent Difference
(SAP2000 vs Independent)
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Percent Difference
(OpenBrIM vs Independent)
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12x2 mesh
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Load case IN
In-Plane
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Uy, in
Average of
jts 13, 26, 39
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Load case OUT
Out-of-Plane
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Uz, in
Average of
jts 13, 26, 39
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