Normal stress
Also: mechanical stress, σ
Internal force distributed over a cross-sectional area.
Average axial stress is F/A; local stress varies near holes, notches, contacts, and bending.
- Units
- pascal (Pa = N/m²)
- Formula
σ = F/A
Example 900 N over 30 mm² gives 30 MPa average stress.
Common misconception Low average stress does not rule out a local stress concentration or another failure mode.