Analysis & loading · Sections & mechanics
Mohr circle explorer calculator
Principal stresses, maximum shear and the stresses on any plane. Change θ and watch the point move around the circle, with a Mohr–Coulomb envelope for comparison.
Standard: 2D stress transformation · principal stresses
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Inputs in the worked example
The live calculator starts with these values; change any of them and every result, check and diagram updates instantly.
| Input | Value | Unit |
|---|---|---|
| σx | 120 | kPa |
| σy | 40 | kPa |
| τxy | 35 | kPa |
| Plane angle θ | 30 | ° |
| Strength c′ | 20 | kPa |
| Strength φ′ | 32 | ° |
Worked example — results
| Result | Value | Unit |
|---|---|---|
| Centre (σx + σy)/2 | 80.00 | kPa |
| Radius | 53.15 | kPa |
| σ1 | 133.15 | kPa |
| σ3 | 26.85 | kPa |
| Principal angle θp | 20.59 | ° |
| σn on θ plane | 130.31 | kPa |
| τ on θ plane | -17.14 | kPa |
| Mobilised strength ratio | 0.895 |
- ✓ Circle below Mohr–Coulomb envelope — 0.90
Method, formulas and assumptions
- σn = (σx+σy)/2 + (σx−σy)/2·cos2θ + τxy sin2θ
- τ = −(σx−σy)/2·sin2θ + τxy cos2θ
- Mobilised ratio = R/(c′cosφ′ + s sinφ′); ≥ 1 means failure
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For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.