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Sound in engineering

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Sound in engineering

  1. 1.   Dr. ir. Eva Lantsoght 3/31/2015 Sound Applications in Engineering 1
  2. 2.  General applications  Applications in bridge engineering o NDT techniques o Acoustic emission o => Proofloading  Summary 3/31/2015 Sound Applications in Engineering 2
  3. 3.  Sound in Engineering? Acoustic Engineering o Design, analysis and control of sound  Applications o Noise control: reduce unwanted noise o Ultrasound o Programming digital sound of synthesizers 3/31/2015 Sound Applications in Engineering 3
  4. 4.  Design of building ~ sound experience  Depends on the use of the building o Theatre: good speech intelligibility o Concert hall: quality of sound of music o Offices: pleasant space, not too noisy 3/31/2015 Sound Applications in Engineering 4
  5. 5.  Noise pollution = disturbances caused by unwanted sounds o Transport o Industry o Recreation  Civil Engineering o Development of better material mixes to reduce noise levels of traffic o Open graded asphalt 3/31/2015 Sound Applications in Engineering 5
  6. 6.  Used in The Netherlands (ZOAB)  “Whisper asphalt”  Very porous mix o More coarse material o Less fine material  Advantages o Noise reduction: 4dB at 120km/h o Drainage of water – no aquaplanning o No rutting  Disadvantages o Less friction => longer distance when breaking o Raveling problems o Shorter lifetime than regular asphalt 3/31/2015 Sound Applications in Engineering 6
  7. 7.  Extending the service life of existing bridges o Improved calculation methods o Improved inspection methods o Improved rehabilitation methods  Inspection: o Visual inspection o Non-destructive inspection o Destructive inspection o Proofloading 3/31/2015 Sound Applications in Engineering 7
  8. 8.  Non-destructive testing method  Evaluation of material properties (e.g. E-modulus)  For near surface zone  Surface wave dispersion o Velocity of propagation as function of frequency and wavelength o In layered system o To obtain information about layer thickness and E 3/31/2015 Sound Applications in Engineering 8
  9. 9. 3/31/2015 Sound Applications in Engineering 9
  10. 10.  More commonly used – with electro-magnetic waves (not sound waves)  Objects inside depth of concrete o Reinforcement o Wire meshes  Produces contour maps of subsurface features 3/31/2015 Sound Applications in Engineering 10
  11. 11.  Fast methods: o Where sound changes from clear ringing to mute and hollow  Finds delaminations in concrete 3/31/2015 Sound Applications in Engineering 11
  12. 12.  Stress-wave based method  Detection of defects in concrete o Delamination  Detect wave reflectors  Frequency range 3 - 40 kHz 3/31/2015 Sound Applications in Engineering 12
  13. 13.  Dynamic response characteristics to a given impulse excitation  Lower range than impact echo o 0 – 1kHz 3/31/2015 Sound Applications in Engineering 13
  14. 14.  Combine methods to get overview of condition of bridge  More info: NDToolbox o www.ndtoolbox.org
  15. 15.  Acoustic waves emitted by material  Caused by irreversible change in internal structure o Crack formation o Plastic deformation  Transient elastic waves  < 1kHz – 100MHz o For applications: 100 kHz – 100 MHz  Event => measurement “hit” 3/31/2015 Sound Applications in Engineering 15
  16. 16.  Use acoustic emission during proofloading  Information about cracks before we can see them  Combine with other measurement techniques 3/31/2015 Sound Applications in Engineering 16
  17. 17.  Levels of assessment of bridges o Hand calculation o Linear finite element calculation o Non-linear finite element calculation o Probabilistic analysis o Coupling probabilistic + NLFEA  Still uncertainties? o Proofloading until different load levels • No permanent damage • Unfit for use level • Repair level 3/31/2015 Sound Applications in Engineering 17
  18. 18.  Extend service life of existing infrastructure  Effect of deterioration of materials on structural performance  Test 1 bridge o But information valid for subset of bridge stock 3/31/2015 Sound Applications in Engineering 18
  19. 19.  Proofloading to assess capacity of existing bridge  Study cracks and deformations for applied loads  Crack formation: acoustic emissions measurements  Ruytenschildtbrug: testing to failure
  20. 20.  Sound in Engineering – many applications  General applications: think about effects of sound for buildings, pavements, ..  Application to bridges o NDT techniques for better inspection o Acoustic emission as measurement technique o Acoustic emission used in proofloading 3/31/2015 Sound Applications in Engineering 21
  21. 21. Contact: Eva Lantsoght E.O.L.Lantsoght@tudelft.nl elantsoght@usfq.edu.ec

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