Patch test
StaticPASS · 0%Baseline element correctness on a coarse, irregular mesh
- Tolerance:
- 5%
Problem statement
- Geometry
- A small patch of 4–5 irregularly shaped (non-rectangular) elements assembled together. Exact dimensions aren't fixed — the test checks the method, not a specific geometry.
- Material
- Linear-elastic isotropic material, arbitrary E and ν (the test is invariant to the actual values).
- Boundary conditions
- Boundary nodes of the patch are given prescribed displacements matching an exact uniform strain field.
- Measured quantity
- Stress/strain at the interior nodes of the patch — must exactly reproduce the prescribed uniform field.
Results comparison
| Reference value | Exact affine field: σ_ii = 2000 Pa, σ_ij = 400 Pa, u is linear |
| Our result | Maximum deviation in σ and |u|: 8.53e-14% |
| Deviation | 0% |
| Tolerance | 5% |
| Status | PASS · 0% |
| Element family | Solid element |
| Mesh details | hex8 2×2×2 on a unit cube, all non-corner nodes distorted; affine field through constraint equations (26 nodes × 3 ) |
Updated: 2026-07-10 · WebCAE solver