1. What is Hoop Stress?

Hoop stress (or circumferential stress) is the stress exerted circumferentially in both the wall of a cylinder subjected to internal or external pressure. It's a crucial parameter in pipe and pressure vessel design.

2. How Does the Calculator Work?

The calculator uses the hoop stress equation:

Where:

• \( \sigma_h \) — Hoop stress (Pa)
• \( P \) — Internal pressure (Pa)
• \( r \) — Pipe radius (m)
• \( t \) — Wall thickness (m)

Explanation: The equation shows that hoop stress increases with higher pressure or larger radius, and decreases with thicker walls.

3. Importance of Hoop Stress Calculation

Details: Calculating hoop stress is essential for ensuring structural integrity of pipes and pressure vessels. It helps determine if the wall thickness is sufficient to withstand internal pressures without failure.

4. Using the Calculator

Tips: Enter pressure in Pascals, radius and thickness in meters. All values must be positive numbers. The calculator will compute the hoop stress in Pascals.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between hoop stress and longitudinal stress?
A: Hoop stress acts circumferentially, while longitudinal stress acts along the length of the pipe. Hoop stress is typically twice as large as longitudinal stress in thin-walled pipes.

Q2: Is this formula valid for all pipe materials?
A: The formula is valid for calculating stress, but the allowable stress depends on material properties like yield strength and safety factors.

Q3: What's the thin-wall assumption?
A: This formula assumes the wall thickness is less than 1/10 of the radius. For thick-walled pipes, a more complex formula is needed.

Q4: How does temperature affect hoop stress?
A: Temperature changes can cause thermal expansion, affecting both dimensions and material properties, which may increase or decrease hoop stress.

Q5: What safety factor should be used?
A: Safety factors depend on application and standards, but typically range from 1.5 to 4 for pressure vessels.