1. What is Poisson's Ratio?

Poisson's Ratio (ν) is a measure of the Poisson effect, which describes the expansion of a material in directions perpendicular to the direction of compression (or contraction when stretched). It's a fundamental material property used in engineering and material science.

2. How Does the Calculator Work?

The calculator uses the Poisson's Ratio formula:

Where:

• \( \nu \) — Poisson's Ratio (dimensionless)
• Lateral Strain — Strain perpendicular to applied force
• Axial Strain — Strain parallel to applied force

Explanation: The negative sign indicates that lateral strain is typically opposite in sign to axial strain (contraction vs. extension).

3. Importance of Poisson's Ratio

Details: Poisson's Ratio is crucial for understanding material behavior under stress, predicting deformation, and designing structures that account for multi-axial strain effects.

4. Using the Calculator

Tips: Enter both strain values as dimensionless quantities (change in length divided by original length). Ensure axial strain is not zero.

5. Frequently Asked Questions (FAQ)

Q1: What are typical values for Poisson's Ratio?
A: Most materials have ν between 0.0 and 0.5. Rubber is ~0.5, steel ~0.3, cork ~0.0. Auxetic materials have negative values.

Q2: Why is the ratio negative in the formula?
A: The negative sign accounts for the fact that materials typically contract laterally when stretched axially (and vice versa).

Q3: Can Poisson's Ratio be greater than 0.5?
A: For isotropic materials, ν > 0.5 would violate energy conservation. Some anisotropic materials may appear to exceed this in certain directions.

Q4: How is Poisson's Ratio measured experimentally?
A: Typically by simultaneously measuring axial and lateral strains during tensile or compression testing using strain gauges or extensometers.

Q5: What's special about materials with ν = 0.5?
A: These are perfectly incompressible materials (like rubber or water under small strains) that maintain constant volume when deformed.