FP6 priority

1.1.4   Aeronautics and Space

1.4.1

Title of the proposal

MODELLING OF WAVES PROPAGATION IN IMPACTED BODIES BY USE OF FINITE ELEMENT METHOD

Institute

Slovak Academy of Sciences, Institute of Materials and Machine Mechanics
Branch Martin, Severna 14, SK-036 80 MARTIN, Slovak Republic

Contact

Research subject for a potential FP6 project

Our contribution for a potential FP6 project could be in modifications of our approaches for their applications in the FP6 priority thematic area. The part of our present capabilities (in the waves propagation modelling) is demonstrated below.

Table 1 Comparison of exact and numerical dimen-sionless natural frequencies of the thick hollow cylinder for H / Rm = 0.2, H / L = 0.2, n = 7 and μ = 0.3 .
Legend: H - thickness, Rm - middle radius, L - length,n - number of circumferential waves and μ - Poisson\'sratio. The exact solutions were executed by using complicated approach from the paper “D. C. Gazis, J. Acoust. Soc. Am. 30, (1959), 568-573“. The FEM model consists from 250 three-noded finite elements. The maximum relative error among 20 lowest values (solved in one task) was less than 0.00001% !

Figure 1 The inteferogram of thebending waves propagation at the 55 μs after the impact versus its finite elementapproximation.Bending waves in the thin steel opened cylindric shell were generated by ultra short impuls of duration about 30 ns.
Holointeferometry - J. Trnka Inst. of Therm. CAS, Prague
FEM - T. Mazuch IMMS SAS, Martin

For more informations see the personal web-page:

http://www.savmt.sk/STAFFS/mazuch.htm

Recent international cooperation of the research team

Institute of Thermomechanics, Czech Academy of Sciences, Prague, Czech Republic (Dr. Jaromir Horacek - analytical approaches, Dr. Jan Trnka - holointeferometry , Jan Vesely – experiments by the modal method and Dr. Jan Kozanek - other numerical approaches). The cooperation have resulted in 12 joint publications (J. Sound. Vibr., J. Comput. and Appl. Mathematics, Mechanical Engineering, Engineering mechanics, Proceedings ...) and 14 (12 ISI) citations.

Proposer´s relevant publications related to the research subject

[1] MAZUCH, T.: Waves dispersion modelling in anisotropic shell and rods by finite element method. Journal of Sound and Vibration. 198(4), 1996, p. 429-438.
[2] MAZUCH, T. – HORACEK, J. – TRNKA, J. – VESELY, J.: Natural modes and frequencies of thin clamped-free steel cylindrical storage tank partially filled with water: FEM and measurement. Journal of Sound and Vibration 193(3), 1996, p. 669-690.
[3] MAZUCH, T.: Variant finite element applications to axisymmetric wave dispersion analysis of cylinders. Journal of Composite Materials 33(15), 1999, p. 1390-1409.
[4] MAZUCH, T.: Influence of ideal fluid on dispersion of axisymmetric waves propagated in infinite hollow cylinder. Journal of Sound and Vibration 245(4), 2001, p. 611-631.
[5] MAZUCH, T. – TRNKA, J.: Stress waves in thin shells – numerical solution and experiment. In: Colloquium Dynamics of Machines 2000, IT AS CR, Prague, February 8-9, p. 129-132.