Press fit calculation — fixed 23mm interface diameter
Contact pressure, friction force/torque and stresses for an interference fit (Lame equations), with the interface diameter fixed at 23mm as in the original locked demo page.
Stresses
The legacy "please login" demo lock froze the interface diameter d to 23 mm (also the page's own default). Every other input (bore/outer diameters, length, interference, friction, moduli, Poisson ratios) was already free to vary under the lock and remains free here — the formula itself is identical to the unlocked e3_8 model (press-fit.ts). Interference δ is typically δ/d ≈ 0.001 and should be corrected for surface roughness; assumes stresses stay below the elastic limit. Independently of the diameter lock, if the entered bore/outer diameters are physically invalid relative to the fixed interface diameter (outer diameter smaller than the bore, or a negative bore), the legacy source silently discards both and substitutes its own defaults (dᵢ=20 mm, dₒ=80 mm) rather than rejecting the input — preserved exactly, with no separate output showing the diameters actually used. Separately, entering dₒ=0 is a supported special case (unlike the reset above) — the legacy source treats it as an effectively infinite outer diameter (a very thick outer part with no defined outer boundary), substituting a large finite stand-in value rather than 0 itself; this is not indicated in the field label.
Method & references
- Lame’s equations for thick-walled cylinders (elastic regime).
- Default values represent a bronze bush in a steel flange.
- FIXED GEOMETRY: interface diameter d = 23 mm — the original login gate forces this value regardless of input; see notes.
The computation is a literal port of the original client-side JavaScript from /calculators/c5_14.htm. Results are verified equal to the original by an automated golden-master test. No formula has been re-derived or “improved”.