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Damping capacity of metallic materials

Damping capacity of metallic materials. Drd. Nicanor Cimpoesu Faculty S.I.M. Iasi. Damping capacity. High damping capacity has been one of the most important properties of materials used in engineering structures where undesirable noise and vibration are to be passively attenuated.

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Damping capacity of metallic materials

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  1. Damping capacity of metallic materials Drd. Nicanor Cimpoesu Faculty S.I.M. Iasi

  2. Damping capacity • High damping capacity has been one of the most important properties of materials used in engineering structures where undesirable noise and vibration are to be passively attenuated.

  3. Materials with damping capacity • Rubbery membrane type EPDM used as elastic ecologic sheets proofing for accumulation reservoirs of residual waters results from different technological fabrication processes, ornamental lakes, swimming pools, fishy pools, ecological garbage holes, roofs, canals, tunnels which on internal friction test have 0.8 value at 1 Hz testing frequency for -40 °C temperature and value of 0.85 at 100 Hz frequency and -25 °C. • A steel sample was analyzed as extreme value of internal friction which has a maximum value of 0.005 at 1 Hz but also an adhesive with low viscosity with a value 6 for internal friction at –20 °C. between this value tests reveal a value of 0.2 for internal friction at a quartz material at 580 °C and for an composite between a epoxy resin and carbon fibers with values 0.086 at 190 °C for first test and 0.082 still for 190 °C but second test.

  4. Shape memory materials • This unusual property for a metallic material author named “rubbery behavior” and after year 1951 scientific people study many different alloys most common being Ni-Ti (nitinol), Cu-Al-Zn and Cu-Al-Ni which have a lot of practical applications.

  5. Internal friction and shape memory alloys • A particularly interesting class of devices is linked to the application of particular kinds of ‘‘smart materials’’ to engineering structures. • Particularly interesting for their properties, linked to microcrystalline phase transition processes, are the shape memory alloys (SMA-s). • SMA-s exhibit a particular behaviour that makes them quite promising for civil engineering applications, especially for the realization of new semi-active control devices. • Internal friction is measured frequently with a system moved with certain amplitude and after that left free to vibrate so the amplitude will decrease.

  6. Shape memory alloy used in structures applications

  7. Internal friction versus temperature

  8. Chemical analysis of SMA-s

  9. Dilatometry tests

  10. Optical microscope micrographs

  11. Scanning electron microscopy's

  12. EDX study of investigated alloys

  13. EDX study of investigated alloys second part

  14. EDX study of investigated alloys third part

  15. Equipment for internal friction study type torsion pendulum

  16. Results obtained with torsion pendulum

  17. Equipment for internal friction study type DMA

  18. Internal friction measured with DMA of a SMA based CuZnAl

  19. Internal friction measured with DMA of a SMA based CuZnAl

  20. Application of a shape memory alloy memory effect + big internal friction

  21. Concluzions • Un aliaj cu memoriaformei, obtinut cu costuriredusesi care poseda un bun efect de memoriaformei, a fostrealizat din metale de puritateridicatacupru, zinc sialuminiu. • Aliajulobtinut Cu68,6 Zn13,2Al4,85prezintaefect de memoriaformeiceeacereprezinta un avantaj in utilizareaacestuia in diferiteaplicatii ca element de disipare a energieidatoritavalorilorridicatepe care le prezintafrecareasainterna. • Valoareafrecarii interne la temperaturacamereiesterelativscazutapentruaplicatii practice darmai mare decat a materialelormetalice in general. Valoarearidicata a frecarii interne (0.116) la temperatura de 89,73 °C face din acestaliaj o posibilasolutie a problemelor de seismicasivibratiiputandfiutilizat ca element de disipare a energieimentinand in acelasitimpproprietatile de material metalic. • Este prezentatasiinfluentatemperaturiiasupravalorilorfrecarii interne cu punerea in evidenta a domeniuluiundeintalnimceamai mare valoare a amortizariipunand in evidentapunctele de transformare ale aliajuluisidomeniulundefazamartensiticaesteimpreuna cu ceaaustenitica. • In investigatiile legate de frecareainterna se observasilegaturadintremodulul de elasticitate a unui material sicapacitateasa de amortizarefiindcoordonate de cauzesimilare.

  22. This paper was sustain by PCE-IDEI grant 616, project 83/01.10.2007 Thanks : • Prof. Dr. Ing. Hopulele Ion • Conf. Dr. Ing. Stanciu Sergiu THE END

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