Laboratory for Dynamics of Machines and Structures 
Including directly measured rotations in the virtual point transformation
 T. Bregar, N. Holeček, G. Čepon, D. J. Rixen and M. Boltežar
Mechanical Systems and Signal Processing, p. 106440, October 2019

download pdf   https://doi.org/10.1016/j.ymssp.2019.106440
Abstract
Dynamic substructuring methods serve as a powerful tool in the analysis of modern complex systems. The coupling of substructures has been successful with analytically obtained results. However, substructuring with experimentally obtained data remains challenging. One of the main problems associated with experimental substructuring is the coupling of the rotational degrees of freedom (RDoFs). A promising method where RDoFs are included implicitly is the virtual point transformation. Even though the transformation has been successfully used in the substructuring process, it is still highly susceptible to inaccuracies in the sensor sensitivity and positioning. In this paper an expansion to the virtual point transformation is proposed, which enables the projection of a directly measured rotation response on the interface deformation modes. A novel formulation of the weighting matrix is introduced to consistently include the measured rotations in the transformation. The proposed expansion is demonstrated on a numerical model of a simple beam-like structure and compared with the standard transformation. The effects of inaccuracies in the sensor sensitivity and placement on the overall quality of both transformation are analysed with a global sensitivity analysis. Finally, an experimental validation of the proposed expansion is carried out on a steel beam.
Authors

Associate PhD student

Tomaž Bregar, PhD Student

  Gorenje d.d.
  
  +386 1 4771 230


,

  
  
  

Associate Professor

Gregor Čepon, PhD

  Ladisk, Faculty of Mechanical Engineering, University of Ljubljana
  gregor.cepon@fs.uni-lj.si
  +386 1 4771 229
Scholar Home Xs


,

  
  
  

Professor

Miha Boltežar, PhD

  Ladisk, Faculty of Mechanical Engineering, University of Ljubljana
  miha.boltezar@fs.uni-lj.si
  +386 1 4771 608
Scholar Home Xs