Teilinstitut Dynamik/Mechatronik - Mitarbeiter
Institut für Technische Mechanik

M.Sc. Jens Burgert

  • Postanschrift:
    Karlsruher Institut für Technologie
    Institut für Technische Mechanik
    Teilinstitut Dynamik/Mechatronik
    Postfach 6980
    76049 Karlsruhe

    Haus- und Lieferanschrift:
    KIT-Campus Süd
    Institut für Technische Mechanik
    Teilinstitut Dynamik/Mechatronik
    Geb. 10.23, 2.OG
    Kaiserstraße 10
    76131 Karlsruhe

Optimized wave propagation based on the example of percussion drilling

Experimental results of an impact recorded with a high speed camera

Impacting rods are used in various devices in practical life but also for scientific experiments. Examples are rock drilling and piling machinery, while the Hopkinson split bar is used for testing materials. The typical arrangement is a primary rod with a tool at the end contacting the process material and a free tip, onto which a piston rod is hitting with a given kinetic energy. The hit is followed by a complicated sequence of phenomena. A stress wave, whose length is double the physical length of the piston rod, starts to propagate along the primary rod to finally reach the tool-process material interface. In case of rock drilling machine, a nonlinear penetration of the bit into the rock takes place and a reflecting wave component is generated. In the Hopkinson apparatus the test specimen experiences axial deformations and the stress wave is split into reflecting wave in the primary rod and into transmitted wave in the secondary rod beyond the test specimen. In the long history of rock drilling, fundamental mechanisms contributing to the effective drilling process are still unknown. To produce maximal tool penetration for each hit, rules have to be derived which specify the dimensioning of the piston and drill rod. Recent investigations, that cover the issue of optimization, are revealing that the efficiency of the drilling process strongly depends on the shape of the longitudinal wave transmitted through the drill rod to the drill bit. A well-known fact is that the cross-sectional profile of the piston is shaping the stress wave profile. Therefore, the main object of the research project is to adjust the geometrical form of the impacting piston for an optimized shape of the stress wave from which a maximal penetration follows.



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Pneumatic single hit test rig for analysis of the stress wave profile of non-uniform impacting rods.
Burgert, J.; Seemann, W.; Moilanen, C.; Montonen, J.; Miettinen, J.; Saarenrinne, P.
2018. Proceedings of ISMA2018, International Conference on Noise and Vibration Engineering/USD2018, International Conference on Uncertainty in Structural Dynamics : Leuven, Belgium, 17 - 19 September, 2018. Ed.: W. Desmet, 3535–3547, KU Leuven, Department of Mechanical Engineering, Heverlee
Measuring the wave shape and wave propagation speed of two impacting rods of arbitrary cross section and material.
Burgert, J.; Seemann, W.
2019. 26th International Congress on Sound and Vibration 2019 (ICSV26), Montreal, Canada, 7 - 11 July 2019, 199–206, Curran, Red Hook NY)
Comparison of a numerical versus an analytical approach to calculate 1D impact problems of non‐uniform cross sections.
Burgert, J.; Seemann, W.
2018. Proceedings in applied mathematics and mechanics, 18 (1), e201800250. doi:10.1002/pamm.201800250
Numerical method to determine the inverse solution of two impacting rods of non‐constant cross section.
Burgert, J.; Seemann, W.
2019. Proceedings in applied mathematics and mechanics, 19 (1), Articel: e201900007. doi:10.1002/pamm.201900007
Optimization of the piston geometry to generate a desired stress wave shape.
Burgert, J.; Seemann, W.; Hartenbach, F.
2017. Proceedings in applied mathematics and mechanics, 17 (1, SI), 675–676. doi:10.1002/pamm.201710306