Hertz initial point contact — load from prescribed contact pressure
For a ball on a flat, computes the effective modulus, effective radius, initial contact diameter, indentation and contact load corresponding to a prescribed mean contact pressure (e.g. the onset of yield, pmc = Rp0.2).
Initial contact diameter, d = 2r607.9 µm
Indentation, δ18.48 µm
Contact load, Fc870.71 N
Effective Young’s modulus, E′232.6 GPa
Effective contact radius, R′2.5 mm
Method & references
- Hertz point-contact theory (ball on flat), solved for load given a target mean contact pressure.
- Legacy page also has a separate "Brinell Hardness / plastic deformation" section (solve1) — a distinct plasticity/indentation-hardness model, not part of the Hertz contact family, and not ported here.
The computation is a literal port of the original client-side JavaScript from /calculators/p4_5.htm. Results are verified equal to the original by an automated golden-master test. No formula has been re-derived or “improved”.