1. What is True Stress?

True stress is the actual stress experienced by a material during deformation, accounting for the changing cross-sectional area. Unlike engineering stress which uses the original area, true stress uses the instantaneous area during deformation.

2. How Does the Calculator Work?

The calculator uses the true stress formula:

Where:

• \( \sigma_{true} \) — True stress (Pa)
• \( \sigma_{eng} \) — Engineering stress (Pa)
• \( \varepsilon_{eng} \) — Engineering strain (dimensionless)

Explanation: The formula accounts for the increasing stress due to the reduction in cross-sectional area as the material elongates.

3. Importance of True Stress Calculation

Details: True stress provides a more accurate representation of material behavior during plastic deformation, especially important for finite element analysis and material modeling.

4. Using the Calculator

Tips: Enter engineering stress in Pascals (Pa) and engineering strain (dimensionless). Engineering strain should be ≥ 0.

5. Frequently Asked Questions (FAQ)

Q1: When should I use true stress instead of engineering stress?
A: True stress should be used when analyzing material behavior beyond the yield point, especially during plastic deformation.

Q2: What's the difference between engineering and true strain?
A: Engineering strain uses original length, while true strain uses instantaneous length. For small deformations (<5%), they are nearly identical.

Q3: Can I use this for compressive stresses?
A: Yes, but the strain should be negative for compression, and the formula remains the same.

Q4: What are typical values for engineering strain?
A: For metals, elastic strains are typically <0.005, while plastic strains can range up to 0.5 or more before fracture.

Q5: How does this relate to stress-strain curves?
A: Engineering stress-strain curves peak at ultimate tensile strength, while true stress-strain curves continue rising until fracture.