Vibration Analysis in Production Testing

www.polytec.com The dynamic properties of structures can be described with the aid of eigenfrequencies, attenuation and eigenshapes. Suitably measured, analyzed and classified, these properties can quickly determine quality for pass/fail selection of manufactured components. For many production inspection applications, Laser-Doppler vibrometers offer significant advantages over conventional, structure-born noise sensors, such as contact accelerometers. Apart from the high dynamic range, wide bandwidth and small spatial measurement spot, it is the non-contact, nonreactive measurement of a laser vibrometer that plays a decisive role. There are many high performance methods available to analyze vibration signals (see table on page E24). In this tutorial, the basic principles of frequency analysis are introduced including two versions of frequency band analysis: short-term Fourier analysis and order analysis. F O R B E G I N N E R S A N D E X P E R I E N C E D U S E R S