Research Article
Free Vibration of Laminated Composite Hypar Shell Roofs with Cutouts
Table 5
Clamping options for +45/−45/+45/−45 hypar shells with central cutouts having a′/a ratio 0.2.
| Number of sides to be clamped | clamped edges | Improvement of frequencies with respect to simply supported shells | Marks indicating the efficiencies of clamping |
| 0 | Simply supported no edges clamped (SSSS) | — | 0 | 1 | (a) Along (CSSS) | Slight improvement | 9 | (b) along (SSCS) | Slight improvement | 9 | (c) along (SSSC) | Slight improvement | 10 | 2 | (a) Two alternate edges (CSCS, SCSC) | Good improvement | 22 | (b) Two adjacent edges (CSSC, CCSS) | Marked improvement | 52 | 3 | 3 edges excluding CSCC | Remarkable improvement | 72 | 3 edges excluding CCSC | Remarkable improvement | 72 | 3 edges excluding CCCS | Remarkable improvement | 72 | 4 | All sides (CCCC) | Frequency attains a maximum value | 100 |
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