Verificação de Olhal de Içamento
Verifique a geometria e a capacidade de tensão do olhal de içamento conforme DNV-ST-E273.
Documentação
About the Calculator
This tool verifies pad eye geometry and stress capacity according to DNV-ST-E273 Appendix A (Portable Offshore Units). It evaluates clearance, geometry, bearing pressure (Hertzian contact), and tear-out capacity.
Methodology
$$ P_{design} (RSF) = SWL \cdot DAF $$
1. Geometry Checks
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Pin/Hole Clearance: A maximum clearance of 6% is typically recommended.
$$ \text{Clearance} (\%) = \frac{d_{hole} - d_{pin}}{d_{pin}} \cdot 100 \le 6\% $$
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Radius Check:
$$ R_{pad} \ge d_{hole} $$
2. Bearing Pressure (Appendix A.3)
The bearing verify checks if the allowable stress $\sigma_e$ is sufficient to resist the contact pressure. Depending on pin fit, one of the following criteria applies:
If $d_{pin} \ge 0.94 \cdot d_{hole}$:
$$ \sigma_e \ge 0.045 \cdot \sqrt{\frac{RSF \cdot E}{d_{hole} \cdot t_{total}}} $$
If $d_{pin} < 0.94 \cdot d_{hole}$:
$$ \sigma_e \ge 0.18 \cdot \sqrt{RSF \cdot \left(\frac{1}{d_{pin}} - \frac{1}{d_{hole}}\right) \cdot \frac{E}{t_{total}}} $$
3. Tear out (Appendix A.4)
Checks the material capacity above the hole.
$$ \sigma_e \ge \frac{2 \cdot RSF}{(2 \cdot R_{pad} - d_{hole}) \cdot t_{total}} $$
References
- DNV. (2016). DNV-ST-E273 Portable Offshore Units. Appendix A. Det Norske Veritas.