Experimental Modal Analysis: Efficient Geometry Model Creation Using Optical Techniques

Abstract

Experimental modal analysis (EMA) is widely used to characterize the dynamic properties of structures. Recently EMA is being used on more complex structures often involving hundreds of measurement points. Modal analysis results are frequently used in combination with numerical models, imposing higher standards on the quality of the modal parameter estimation and the accuracy of the geometry models. These requirements are often contradictory to the availability of test cells and prototypes. In order to solve this challenge, innovative solutions using optical techniques have been developed that simplify and accelerate the creation of a geometrical model of a test object, while at the same time increase the accuracy of measured coordinates. Industrial applicability of these techniques is proven by a number of benchmarks on real-life structures.

Smart Localization of Microphones inside an Automotive Cabin

“…The achieved accuracy depends on the proper setup of the panels (i.e. requiring a skilled test operator), but is 0.4 mm or smaller for a typical setup (2,14) . Although such a method is an appealing solution for applications where sensors are instrumented on car exteriors (e.g.…”

“…Automatic methods, which reduce this setup time and which yield more accurate results, are therefore highly sought for. Currently available solutions include photogrammetry (2) and geometry scanning systems (3) . Although these solutions are effective, they often require expensive devices, which moreover can only be used by highly specialized technicians or may be impractical to use in complex environment such as an automotive cabin.…”

Optical measurements of multi-megawatt wind turbine dynamic response

“…Thus, a broad range of photogrammetric and interferometric techniques have been used both in laboratories with small measurement volumes and for large volumes in the field (Ozbeck and Rixen, 2013). Examples of these applications include 3D shape modeling, reverse engineering (Meyer et al, 2005;Pauwels et al, 2006;Armesto et al, 2009), dynamic or static deformation measurements (Schmidt et al, 2003a;Haritos et al, 2006;Pappa et al, 2003a;Grytten et al, 2007;Chang and Ji, 2007;Chang, 2007;Simpson et al, 2007), system identification and modal analysis (Ji and Chang, 2006;Black and Pappa, 2004;Pappa et al, 2003b;Helfrick et al, 2008;2009;Warren et al, 2009). Photogrammetric and interferometric techniques have also been used on wind turbines (Corten and Sabel, 1995;Corten, 1996;Ozbek and Rixen, 2013;Ozbek et al, 2009;Ozbek et al, 2010;Grosse-S et al, 2014;Zendehbad et al, 2017b).…”