Standards and theory
The standards and the theory behind the results: what each method assumes and where it stops.
- Units and number entry The base units the engine works in, the metric and US customary display, the units you can type into a field, what always stays metric, and the unit rules of the axm command line.
- Rating life (ISO 281) Basic and modified rating life of rolling bearings after ISO 281:2007: load ratings, the reliability factor a1, the life modification factor aISO with κ, eC and Cu, the system life, and how the app applies them.
- Static load rating and static safety The basic static load rating C0 and the static safety s0 of rolling bearings after ISO 76:2006, and how the app derives both from Hertz contact at the actual groove radii.
- Equivalent bearing load The dynamic equivalent load P of ISO 281 with X, Y and e, why the app uses the ISO/TS 16281 reference load from the element loads instead, and how load cases combine into one life by the Palmgren–Miner rule.
- Hertz contact and subsurface stress Point and line contact after Hertz, the contact ellipse, curvature sum and maximum pressure, the shear stresses below the surface, the case depth rule, and the app's maxShearStress, maxShearDepth and suggestedCaseDepth.
- Internal load distribution (ISO/TS 16281) How the app shares a bearing's load among its rolling elements after ISO/TS 16281: load–deflection laws, clearance and load zone, contact angle change, tilt, roller laminae and crowning, the reference load and life, and why the groove radii matter.
- Lubrication and viscosity Viscosity at operating temperature (Walther, ASTM D341), the rated viscosity ν1 and κ of ISO 281, elastohydrodynamic film thickness with inlet heating and starvation, the film parameter λ, and the grease relubrication interval as the app computes them.
- Bearing friction and thermal speeds Bearing friction torque by Palmgren (M0 + M1) and by the four-component model, seal torque and power loss, the heat balance, the thermal reference speed of DIN ISO 15312, the thermally permissible speed of DIN 732, and the minimum load rules.
- Shaft strength: DIN 743 and FKM How the fatigue and static safety of a shaft is assessed at shoulders, notches and plain sections after DIN 743:2012 or the FKM guideline (7th edition), and how the app applies both methods.
- Deflection, critical speeds and whirl The Timoshenko beam model behind the shaft solution, deflection and tilt limits, bending critical speeds, gyroscopic forward and backward whirl, the Campbell diagram, unbalance response, torsional and axial modes and the negative stiffness of magnetic pull.
- Fits: ISO 286 and press fits (DIN 7190) ISO 286 tolerance grades and fundamental deviations, clearance, transition and interference fits, the elastic press fit of DIN 7190-1 by thick-walled cylinder theory, and how bearing seat fits change the operating clearance.
- Gear rating (ISO 6336) The load factors, the contact stress and tooth root stress of ISO 6336 method B, their permissible values and safeties, the 2019 and 2006 editions, load spectra by ISO 6336-6, and what the rating does not cover.
- Gear scuffing (flash and integral temperature) Why gear flanks scuff, the flash temperature method of ISO/TS 6336-20:2022 and the integral temperature method of ISO/TR 13989-2:2000, the bulk temperature, the safeties SB and SintS and the minima the app uses.
- Bolted joints (VDI 2230) The systematic calculation of a highly stressed single-bolt joint after VDI 2230 Part 1 (2015): the steps R0 to R13, resiliences and load factor, preload losses, tightening, the stress checks, slip, thread engagement, temperature and eccentric loading.