Mechanical Vibrations Calculators
Free and forced vibration, isolation, critical speed, dynamic absorbers, FFT analysis, multi-DOF systems
Mechanical Vibrations studies the oscillatory motion of physical systems — from simple spring-mass-damper models to complex multi-degree-of-freedom structures. Understanding vibration is critical for preventing resonance failures, designing isolation systems, and diagnosing machinery health.
The course begins with free vibration of single-degree-of-freedom (SDOF) systems: natural frequency ω_n = √(k/m), damping ratio ζ, and the three response regimes (underdamped, critically damped, overdamped). Forced vibration under harmonic excitation introduces the concepts of resonance, frequency response, and transmissibility — the foundation of vibration isolation design. Multi-degree-of-freedom (MDOF) systems require eigenvalue analysis to find natural frequencies and mode shapes, and modal superposition to compute total response. Vibration isolation uses compliant mounts to reduce transmitted forces or motion at frequencies above √2 times the natural frequency. Dynamic vibration absorbers (tuned mass dampers) cancel vibration at specific frequencies. Critical speed analysis of rotating shafts prevents resonant whirl that damages bearings and seals. FFT (Fast Fourier Transform) spectrum analysis is the primary diagnostic tool for rotating machinery — converting time-domain vibration signals into frequency-domain spectra that reveal imbalance, misalignment, bearing faults, and gear mesh problems.
Vibration analysis is essential in automotive suspension design, aircraft flutter prevention, earthquake-resistant building design, turbomachinery monitoring, precision manufacturing, and any application where unwanted oscillation must be controlled or eliminated.
Key Concepts
- •Core theory and principles of vibrations
- •Applied problem-solving using industry-standard methods
- •Quantitative analysis with real engineering units and magnitudes
- •Connections to other engineering disciplines
Prerequisites
Calculus
Most engineering analysis courses require differential and integral calculus.
Introductory Physics
Familiarity with basic mechanics and energy concepts provides context for engineering-level analysis.
Vibrations Calculators
Free Vibration SDOF Calculator
Natural frequency, damping ratio, and free response of a single-DOF spring-mass-damper system with decay envelope plot
Forced Vibration SDOF Calculator
Steady-state amplitude ratio, phase angle, and frequency response for harmonically forced SDOF systems
Vibration Isolation Calculator
Transmissibility, isolation efficiency, and required mount stiffness for vibration isolation systems
Critical Speed Calculator
First critical speed of a rotating shaft with disk masses using Dunkerley's and Rayleigh's methods
Dynamic Vibration Absorber Calculator
Design a tuned mass damper: optimal absorber tuning, anti-resonance frequency, and primary system response
2-DOF Natural Frequencies Calculator
Natural frequencies, mode shapes, and frequency response for a 2-degree-of-freedom spring-mass system
FFT Analyzer Calculator
FFT magnitude spectrum, dominant frequencies, and THD from generated or custom time-domain signals
Whirling Shaft Critical Speed Calculator
Critical whirling speed of a shaft with mounted disks using Rayleigh's energy method, with deflection shape plot
Vibration Measurement Calculator
Convert between acceleration, velocity, and displacement; peak/RMS conversions; ISO 10816 severity classification
Seismic Instrument Calculator
Instrument response ratio, phase error, and operating range recommendations for seismometers and accelerometers