experimental modal analysis

Modal Test Pump-Motor & Skid. Skid 1st Natural Frequency at 1X Run Speed.

Motor Driven Agitator Via Right Angle Gearbox. Modal Analysis to Measure Natural Frequencies.

KSC Consulting

Rotating Machinery Reliability

Download Agitator Gearbox Mode
at Gear Meshing Fequency (WMV)

Download Agitator Gearbox and Motor
Scoop Natural Frequency
2X Run Speed (WMV)

Download Agitator Gearbox
Motor Scoop Mount
1st Natural Frequency (WMV)

Download Motor-Pump
Skid Natural Frequency
1X Run Speed (WMV)

Vibration caused by natural frequencies can be very damaging to machines and structures. These natural frequencies and the associated mode shapes can be measured using experimental modal analysis. A force is input to the machine or structure typically using an instrumented hammer or shaker. The amount of force and the frequency span excited are controlled. The structure’s response to the force is measured at various locations typically using accelerometers.

The most commonly used data measurement is the Frequency Response Function (FRF) in units of g’s/lb_f. The FRF provides a very good way of characterizing the dynamic response of a machine or structure.

A 3D model of the test structure is developed in ME’scope. This allows animation of the mode shapes at each of the measured natural frequencies (also called modes).

Once the mode shape of the offending natural frequency is understood, solutions to correct it can be evaluated. ME'scope provides Finite Elements to allow modification of models to evaluate solutions such as adding mass, stiffeners, tuned dynamic absorbers, etc.