SPATIAL TRUNCATION IN MODELS OF NON-LINEAR VIBRATING SYSTEMS

Vibrating systems usually have an infinite number of degrees of freedom (d.o.f.). Since a finite number of measurement d.o.f. can only capture certain deformation patterns, the spatial characteristics of vibrating systems are only partially observed experimentally. This research examines the effects of spatial truncation on non-linear system identification. It is demonstrated that truncation produces frequency correlated noise, which cannot be extracted completely with traditional techniques. The goal of this article is to provide insight and practical recommendations for diagnosing and/or compensating for errors due to spatial truncation in multiple-d.o.f systems. The article demonstrates that non-linear dynamic systems should be instrumented with sufficient sensors; model properties should be used in addition to the input–output data; and additional temporal data should be collected to help diagnose errors due to spatial truncation.