Problem:
How are the c1 and c2 parameters calculated in the WRC 107 local stress analysis when a leg support includes a wear plate?
Solution:
When a wear plate is added to a leg support, AutoPIPE Vessel performs two separate WRC 107 stress evaluations. Understanding these evaluations is key to interpreting the resulting stresses and the calculated values of c1 and c2.
1. Stress Evaluation Considering the Wear Plate Thickness
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- The wear plate increases the local shell thickness.
- However, the loaded area is limited to the actual contact area between the leg and the wear plate.
For specific model:
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- Support Section: Pipe
- Pipe Diameter = 273 mm
- The length of contact (N = 150mm)
- Wear Plate Height = 370 mm
- Wear Plate Extension (E) = 180 mm
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Therefore, the program currently calculates:
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- c2 = min(150/2, (370 - 180) / 2) = 75 mm
- c1 = min(4 × c2, (273 + 2 × 180) / 2 - 180) = 136.5 mm
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The WRC methodology limits the height-to-width ratio to 4:1, which further restricts the calculated loaded area.
2. Stress Evaluation at the Edge of the Wear Plate
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- In this check, the loaded area is based on the wear plate dimensions (Half of the longitudinal and circumferential length).
- The thickness increase provided by the wear plate is not considered in this evaluation.