Structural Dynamics and Aeroelastic System Identification



The department of Structural Dynamics and Aeroelastic System Identification works in the field of the dynamics and vibrations of structures in aeronautics and space technology. Included are, for example, the primary structures (load-carrying structures) of fixed wing aircraft, rotorcraft, and satellites. This involves the experimental and

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numerical analysis of structural vibrations as well as the development and assessment of efficient means of vibration reduction.

In experimental mechanics, the department of Structural Dynamics and Aeroelastic System Identification has been working for many years in the field of ground vibration testing of large aircraft and the modal survey testing of aircraft components and wind tunnel models. The aim of a ground vibration test is the identification of the modal parameters of structures, i.e. eigenfrequencies, damping ratios, mode shapes, and generalized masses. The Institute of Aeroelasticity is outstandingly equipped with hardware and software to efficiently perform ground vibration tests contracted by industry partners.

The Institute of Aeroelasticity operates a multi-axis shaking table for the experimental analysis of spacecraft structures. This test facility is used to investigate the dynamic behaviour of structures when exposed to base accelerations. This is typically required in spacecraft engineering for the acceptance or qualification of flight hardware. In addition to the spacecraft applications, the multi-axis shaking table is also used for comfort analysis and for identification of the inertia properties of the tested structures.

The field of analytical or numerical mechanics is essentially concerned with the combined usage of experimental modal data with finite element models. Application of commercial finite element software is the foundation upon which the different scientific topics are based. Most important is the development of interfaces between commercial finite element software and in-house analysis codes, which are available for different scientific applications in structural dynamics and aeroelasticity.

The following list is a summary of the scientific focal points of the department of Structural Dynamics and Aeroelastic System Identification at the Institute of Aeroelasticity:

  • Application and development of ground vibration test techniques (experimental modal analysis, phase resonance testing, efficient vibration excitation, etc.)
  • Development and examination of output-only modal analysis methods in aerospace engineering and for the aeroelastic certification of aircraft in particular
  • Significant methods for the correlation of experimental modal data with finite element predictions
  • Application and development of model updating techniques for the validation of finite element models, also in terms of non-linear structures and structures with stochastic properties
  • Vibro-acoustic simulations and experiments for improving the understanding of transfer paths for sound transmission in aerospace structures
  • Pre-test analysis methods for the optimization of sensor and exciter positions to streamline modal survey testing efforts in terms of data acquisition and data analysis
  • Dynamic analysis (experimental and analytical) of non-linear structures in the time domain and in the frequency domain
  • Efficient interfaces between structural dynamics and aeroelastic analysis to support the generation of aerodynamic models to be used for flutter analysis
  • Uncertainty propagation in flutter analysis to assess flutter stability for structures with scattered experimental modal data
  • Structural modification and modal coupling techniques for the dynamic analysis of assembled structures or, respectively, for the assessment of structural modifications in the absence of analytical models

Contact
Dr.-Ing. Marc Böswald
German Aerospace Center

Institute of Aeroelasticity
, Structural Dynamics and Aeroelastic System Identification
Tel: +49 551 709-2857

Fax: +49 551 709-2862

E-Mail: Marc.Boeswald@dlr.de
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