Mean Diameter of Skirt in Vessel Calculator

Mean Diameter of Skirt Formula:

\[ D_{sk} = \sqrt{\frac{4 \times M_w}{\pi \times f_{wb} \times t_{sk}}} \]

Mean Diameter of Skirt (D_sk):

1. What is Mean Diameter of Skirt in Vessel?

Definition: The mean diameter of skirt in a vessel is a critical dimension that depends on the vessel's size and design, calculated based on wind loads and structural stresses.

Purpose: This calculation ensures the skirt (the supporting structure at the base of a vessel) can withstand wind-induced bending moments while maintaining structural integrity.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ D_{sk} = \sqrt{\frac{4 \times M_w}{\pi \times f_{wb} \times t_{sk}}} \]

Where:

\( D_{sk} \) — Mean diameter of skirt (meters)
\( M_w \) — Maximum wind moment (Newton-meters)
\( f_{wb} \) — Axial bending stress at base of vessel (Pascals)
\( t_{sk} \) — Thickness of skirt (meters)

Explanation: The formula calculates the required diameter to distribute wind-induced bending stresses evenly across the skirt's cross-sectional area.

3. Importance of Skirt Diameter Calculation

Details: Proper skirt diameter calculation ensures vessel stability under wind loads, prevents structural failure, and meets engineering design standards.

4. Using the Calculator

Tips: Enter the maximum wind moment, axial bending stress, and skirt thickness. All values must be positive numbers. Results include a ±5% tolerance margin.

5. Frequently Asked Questions (FAQ)

Q1: How is maximum wind moment determined?
A: It's calculated based on wind speed, vessel height, shape factor, and local wind load standards (typically ASCE 7 or equivalent).

Q2: What's a typical axial bending stress value?
A: This depends on the material, but common values range from 80-150 MPa for carbon steel, with appropriate safety factors applied.

Q3: Why is skirt thickness important in this calculation?
A: Thicker skirts can support larger diameters as they provide more material to resist bending stresses.

Q4: Does this calculation include safety factors?
A: The ±5% tolerance accounts for minor variations, but engineers should apply appropriate safety factors based on local codes.

Q5: How does vessel height affect this calculation?
A: Taller vessels experience greater wind moments, which directly increase the required skirt diameter.