Modal analyses, ground vibration testing

Activities:

  • Performing ground vibration tests (GVT)
  • Modal tests of entire structures, aero-elastic scaled models and aircraft structures (e.g. whole aircraft and their components, power plants, propellers, control systems, hydraulic actuators, skin fields and other structures)
  • Definition of modal parameters (frequency, mode shape, damping, generalized mass and stiffness)
  • Excitation of isolated vibration modes by accommodated sinus excitation
  • Sweep harmonic excitation, pulse excitation, white noise excitation
  • Operational modal analyses
  • Graphic display of deformations and nodal lines
  • Animation of mode shapes
  • Modal parameters corrections for the extra mass and stiffness of the tester
  • Orthogonality verification and calculation of vibration mode correlation criteria
  • Transfer function definition for aeroelastic calculations
  • Determining the frequency response function

 

Equipment:

  • Mobile facility for modal tests, GVT (Ground Vibration Tests) using PRODERA tester with circuits to excite constructions by 16-channel system; response measurement at 256 points
  • 32-channel LMS TestLab dynamic signal analyser
  • Software: P-WIN-MODAL to control modal tests
  • Software: LMS TestLab polyMax Modal Analysis
  • Software: MOPAR for modal data processing

 

Research projects:

  • 3AS – “Active Aeroelastic Aircraft Structures“, 2002 – 2005, 5FP EU
  • Research on Strength with Special Regard to Aircraft Structures“, (2004 – 2010, MYES - Research Plan)
  • CESAR – “Cost Effective Small Aircraft“, 2005 – 2009, 6. RP EU
  • W-WING – “Development of aeroelastic demonstrator for whirl flutter research“, 2011 – 2015, MIT – institutional funding)
  • ESPOSA -  ”Efficient Systems and Propulsion for Small Aircraft“, WP2.3 Whirl Flutter  (2011-2015, EC, 7th Framework program of EU, project No. 284859)

 

Contact person:

Ing. Václav Horák, Ph.D., Head of Structural Tests, VZLU
tel: +420 225 115 225, e-mail: horak@vzlu.cz

 

REFERENCES:

  • Hlavatý, V.: Recalculation of Experimental Modal Parameters and Determination of Control Surfaces Inertia Parameters for Subsequent Flutter Analyses Using Experimental Data, Czech Aerospace Proceedings, Issue 1, 2015
  • Čečrdle, J. – Hlavatý, V. : Aeroelastic Analysis of Light Sport Aircraft Using Ground Vibration Test Data, Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering, Vol. 229, Issue 12, pp.2282-2296, 2015, ISSN 0954-4100
  • Hlavatý, V.: Mobile Modal Test Laboratory at VZLU, Czech Aerospace Proceedings, Issue 4, 2010
  • Černý, O. – Hlavatý, V.: Optimization of Exciter Locations for Modal Testing of Aircraft Structures. Czech Aerospace Proceedings, Issue 1, 2009