Elastic and damping properties

Omer Van Der Biest, Gert Roebben, Ren-Guan Duan

Research supported by the 'Impulsprogramma Nieuwe Materialen' of IWT (Flemish Government) and FWO (Belgian Government)

 
Problem statement
 

The elastic properties of a material depend on the bonding type, crystallinity and composition of its components. Damping refers to the capacity of the material to dissipate energy, and is often linked to the mobility of microstructural defects. Our laboratory is equipped with modern Impulse Excitation Technique (IET)-facilities, allowing to solve the evolution of elastic and damping properties as a function of temperature.

The impulse excitation technique (IET)
 

IET is based on the analysis of the vibration of a test sample or component after it was 'impulse excited' (= gently tapped). The resonance frequencies are characteristic for the test object, as they are related to its stiffness, mass and geometry. The relation is accurately known for isotropic objects of simple shape such as bars or disks, thus making IET a standard method to determine elastic moduli of isotropic materials (ref. ASTM E 1876-99, ENV 843-2). Also, small geometrical distortions, density fluctuations, cracks etc. influence the value of the resonance frequencies. Therefore, IET is also used for quality control in materials processing.
High-performance IET-devices
 

  1. GrindoSonic, J. W. Lemmens nv.
    Apparatus to determine fundamental resonance frequencies, equipped with a fully automated impulse excitation furnace allowing to reach temperatures up to 1100°C in air and inert gases.
     
  2. RFDA, IMCE nv
    A digital vibration analysis system, which in addition to determining the resonance frequencies, also considers the rate at which the vibration damps out (= decrease of amplitude with time). Thus the specific damping capacity or internal friction can be evaluated (Rev. Sci. Instr., 68, 4511-4515 (1997)).
     
  3. HTVP-1750-C, IMCE nv
    Graphite furnace for IET-measurements in inert atmosphere up to 1750°C.

Sample suspension system for test in air furnace (Tmax = 1100°C)
 
Application examples
 

Examples of succesfull applications of the IET in our laboratory include:

  1. Detection of residual glass phases in sintered silicon nitride.
  2. Calculation of elastic modulus plasma-sprayed coatings.
  3. Phase transformations in partially stabilised zirconia polycrystals.

References to articles in International Journals in which IET is specifically used:

  • G. ROEBBEN, B. BOLLEN, A. BREBELS, J. VAN HUMBEECK, O. VAN DER BIEST, "Impulse excitation apparatus to measure resonant frequencies, elastic moduli and internal friction at room and high temperature", Review of Scientific Instruments, Vol. 68, pp. 4511-4515 (1997).
     
  • G. ROEBBEN, L. DONZEL, S. STEMMER, M. STEEN, R. SCHALLER, O. VAN DER BIEST, "Viscous energy dissipation at high temperatures in silicon nitride", Acta Materialia, Vol. 46, p. 4711-4723 (1998).
     
  • J. SCHROOTEN, G. ROEBBEN, J. HELSEN, "Young's modulus of bioactive glass coated oral implants by resonance frequency analysis", Scripta Materialia, Vol. 41, p. 1047-1053 (1999).
     
  • G. ROEBBEN, B. BASU, J. VLEUGELS, J. VAN HUMBEECK, O. VAN DER BIEST, "The innovative impulse excitation technique for high temperature mechanical spectroscopy", J. Alloys and Compounds, Vol. 310, p. 284-287 (2000).
     
  • R. G. DUAN, G. ROEBBEN, O. VAN DER BIEST, K. M. LIANG, S. R. GU, "Microstructure research of glasses by impulse excitation tecnique (IET)", J. Non-Crystalline Solids, in press (2000).
     
  • Fatigue resistant silicon nitride ceramics due to anelastic deformation and energy dissipation, G. Roebben, L. Donzel, M. Steen, R. Schaller, O. Van der Biest, J. Alloys and Compounds (0.845), Vol. 310, p. 39-43 (2000)
     
  • The impulse excitation technique for rapid assessment of the temperature dependence of structural properties of silicon nitride and zirconium oxide ceramics, G. Roebben, R. G. Duan, B. Basu, J. Vleugels, O. Van der Biest, Proc. 7th Intl Symp. on Ceramic Materials and Components for Engines, Goslar, Germany, June 2000, ed. by J. Heinrich, F. Aldinger, Wiley-VCH, pp. 217-222 (2001)
     
  • Microstructure research of glasses by impulse excitation tecnique (IET), R. G. Duan, G. Roebben, O. Van der Biest, K. M. Liang, S. R. Gu, J. Non-Crystalline Solids (1.269), Vol. 281, p. 213-220 (2001)
     
  • Stability of intergranular phases in hot pressed Si3N4 studied with mechanical spectroscopy and in-situ high-temperature XRD, R.G. Duan, G. Roebben, J. Vleugels and O. Van der Biest., J. Europ. Ceram. Soc. (0.952), Vol.22, p. 1897-1904 (2002).
     
  • Assessment of the high temperature elastic and damping properties of silicon nitrides and carbides with the impulse excitation technique (IET), G. Roebben, R.G. Duan, D. Sciti, O. Van der Biest, J. Europ. Ceram. Soc., (accepted 2002).
     
  • Transformation-induced damping behaviour of Y-TZP zirconia ceramics, G. Roebben, B. Basu, J. Vleugels, O. Van der Biest, J. Europ. Ceram. Soc., (accepted 2002).
     
  • Thermal stability of in-situ formed Si3N4-Si2N2O-TiN composites, R.G. Duan, G. Roebben, J. Vleugels and O. Van der Biest, J. Europ. Ceram. Soc., (accepted 2002).
     
Detailed information about IET and IET-sample preparation
 

Further details about the Impulse Excitation Technique, on the suitability of specific sample shapes and dimensions, you can find here (in MS Word 97 format)

 

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Last modified: September, the 11th, 2003