Tools
Vibration calculators
Engineering calculators that run in your browser. No install, no sign-up, and nothing you type or load is sent anywhere. Every tool documents its method, assumptions and limits, how it was verified, and the sources behind it, linked to the Resources page.
Skipper Vibration Analysis Suite
A complete offline vibration analysis package for Windows: everything these calculators do one at a time, plus full 3D modelling, in one workflow from raw survey data to finished report. Your data never leaves your machine.
- ScreeningSpectral peaks and overall levels against Energy Institute main-line criteria, ISO 20816-3 zones and your own limits, with spectra shown exactly as measured. EI 2008 US 7,430,914 ISO 20816-3
- Spectrum processingWindow-corrected amplitudes for tones and broadband signals, and interpolated peak frequencies between bins. Harris Gade–Herlufsen Grandke
- Machine diagnosticsPeaks named from each machine's forcing frequencies, fault patterns at every bearing, and trends forecasting when zones C and D will be reached. Randall ISO 20816-3
- 3D models & FE modalPiping, steel and machine trains in 3D. Shear-deformable (Timoshenko) frame elements, B31J flexibility factors and CAESAR II-style restraints, solved by subspace iteration. Przemieniecki Cowper Bathe ASME B31J CAESAR II
- ODS & modal testOperating deflection shapes on the model, and roving-hammer test modes paired with FE modes through a MAC table. Randall
- RotordynamicsLateral critical speeds, unbalance response and stability to API 617, API 610 and API 684. Benchmarked against ROSS: frequencies agree to 1 part in a million. Friswell API 617 API 610 API RP 684 ROSS
- PulsationAPI 618-style acoustic analysis of compressor and pump systems; shaking forces passed straight into the FE model. API 618 Blevins
- FIV & AIVLikelihood-of-failure assessment to the Energy Institute method, verified against published worked examples. EI 2008 Carucci–Mueller Eisinger AFT example Bachoo 2021 GP&LNG 2020
- Stress & fatigueVibration stress against ASME OM-3; rainflow and spectral fatigue (Dirlik, Benasciutti–Tovo, Zhao–Baker) cross-checked against FLife; DNV, BS 7608 and IIW S-N curves. ASME OM-3 ASTM E1049 Dirlik Benasciutti–Tovo FLife DNV-RP-C203 BS 7608 IIW
- ReportsOne-click Word, PDF, PowerPoint and Excel reports, with the references behind every method used.
Validation: every calculation is checked against hand calculations, textbook cases or independent software, typically agreeing within 0.1%, and re-run by an automated test suite on every build.
Not released yet. Follow on LinkedIn for updates · Method sources on the Resources page →
Signal analysis
FFT spectrum analyser
Load a CSV time signal and get a windowed, averaged spectrum with peak list, overall RMS and CSV export.
New · PlanningFFT setup planner
Fmax, lines and averages to sample rate, resolution and acquisition time, with a separation check.
ConversionVibration unit converter
Acceleration, velocity and displacement at any frequency, in peak, RMS or peak-to-peak.
New · ConversionDamping converter
Damping ratio, Q, loss factor, log decrement and half-power bandwidth: enter one, get the rest.
Machinery diagnostics
Structural dynamics
SDOF natural frequency & transmissibility
Natural frequency from stiffness and mass, and the response to a forcing frequency, with a live plot.
Piping / beamsPipe span natural frequency
First four bending modes of a pipe or beam span, with contents and insulation, plus animated mode shapes.
New · PanelsPlate natural frequency
Modes of a rectangular panel (duct walls, enclosures) with mode-shape maps and an excitation check.
RandomMiles' equation
RMS response of an SDOF system to flat random base excitation.
Piping & flow
AIV sound power level
Carucci–Mueller sound power from a valve, PSV or orifice, with choked-flow check and sensitivity.
New · PulsationAcoustic resonance & dead legs
Speed of sound, pipe and side-branch acoustic modes, and the flow velocities that can excite them.
FIVVortex shedding frequency
Strouhal shedding frequency for a cylinder in flow, compared against a structure's natural frequency.
These are for quick checks and preliminary estimates. For design decisions, use your own verified methods and the applicable standards. Spotted a bug or want a calculator added? Message me on LinkedIn.