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GELOMBANG ULTRASONIK

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... aluminium, iron Magnesium, ... pipe, tubing, Forgings, extrusions, die block, casting Lamination, seams, inclusion, Bursts, flaking, porosity, ... – PowerPoint PPT presentation

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Title: GELOMBANG ULTRASONIK


1
GELOMBANG ULTRASONIK
  • PENGERTIAN ULTRASONIK
  • TRANSDUSER ULTRASONIK
  • BAHAN PIEZOELEKTRIK
  • SINYAL ULTRASONIK
  • MEDAN DEKAT DAN MEDAN JAUH
  • APLIKASI ULTRASONIK

2
PENGERTIAN ULTRASONIK
  • Frekuensi tinggi di atas 20 kHz
  • Tidak dapat didengar oleh telinga manusia
  • Panjang gelombang di udara maksimum 17,15 mm
  • Analog dengan sinar ultraviolet
  • Tidak dapat dilihat oleh mata manusia
  • Panjang gelombang di bawah 400 nm
  • Frekuensi minimum di udara 7,5x1014 Hz
  • Frekuensi sangat tinggi (GHz)
  • Microwave Ultrasonic (panjang gelombang ?m)
  • Berbeda dengan pengertian supersonik
  • Bergerak melebihi kecepatan suara (Mach gt 1)

3
TRANSDUSER ULTRASONIK
  • Mengubah energi listrik menjadi energi akustik
  • Bertindak seperti pengeras suara (loudspeaker)
  • Mengubah energi akustik menjadi energi listrik
  • Bertindak seperti mikropon
  • Mampu bertindak sebagai transceiver
  • Pemancar (transmitter) Penerima (receiver)
  • Terbuat dari bahan piezoelektrik
  • Bila mendapat tekanan (piezo)
  • Timbul muatan listrik (elektrik)

4
BAHAN PIEZOELEKTRIK
  • Efek piezoelektrik langsung
  • Bila pelat piezoelektrik diberi tekanan, maka
    akan timbul muatan listrik pada kedua
    permukaannya
  • Pelat juga merupakan kapasitor dengan konstanta
    dielektrik tertentu, timbul beda tegangan
  • Efek piezoelektrik balik
  • Bila pelat piezoelektrik diberi tegangan listrik,
    maka kedua permukaannya mendapat tekanan
  • Pelat juga merupakan bahan elastik dengan
    konstanta elastik tertentu, tebalnya akan berubah
  • Tegangan bolak-balik ? Pelat bergetar

5
  • Bahan Piezoelektrik Alam
  • Kuarsa, garam Rochelle, tourmaline
  • Sangat stabil
  • Sensitivitas rendah
  • Bahan Piezoelektrik Buatan
  • Barium titanate, lead circonate titanate, lead
    metaniobate
  • Sensitivitas tinggi
  • Kurang stabil

6
  • Pelat kuarsa potongan-x (x-cut)
  • Menghasilkan gelombang longitudinal

elektroda
L
7
  • SINYAL ULTRASONIK

8
  • FREKUENSI RESONANSI

9
MEDAN DEKAT MEDAN JAUH
10
N
?
D
Fraunhofer zone
Fresnel zone
11
(No Transcript)
12
  • Contoh 3.1

Sebuah transduser ultrasonik yang biasa digunakan
di bidang kedokteran berdiameter 1/2 inci (12,7
mm) dengan frekuensi resonansi sebesar 5 MHz.
Jaringan tubuh manusia mempunyai kecepatan
gelombang rata-rata sebesar 1500 m/s. Hitung
jarak medan dekat dan setengah sudut
penyebarannya.
Jawab
13
  • Contoh 3.2

Sebuah transduser ultrasonik yang biasa digunakan
pada uji tak rusak (UTR) berdiameter 1 inci (25,4
mm) dengan frekuensi resonansi sebesar 2 MHz.
Bahan baja mempunyai kecepatan sebesar 5850 m/s.
Hitung jarak medan dekat dan setengah sudut
penyebarannya.
Jawab
14
  • Contoh 3.3

Sebuah transduser ultrasonik yang biasa digunakan
pada pengukuran aliran gas berdiameter 1/2 inci
(12,7 mm) dengan frekuensi resonansi sebesar 100
kHz. Gas mempunyai kecepatan sekitar 400 m/s.
Hitung jarak medan dekat dan setengah sudut
penyebarannya.
Jawab
15
  • Contoh 3.4

Sebuah transduser ultrasonik yang biasa digunakan
pada pengukuran aliran gas berdiameter 1/2 inci
(12,7 mm) dengan frekuensi resonansi sebesar 100
kHz. Gas mempunyai kecepatan sekitar 400 m/s.
Transduser ini memancarkan gelombang ultrasonik
dengan intensitas sebesar Io. Hitung intensitas
pada suatu titik yang berjarak 200 mm di depan
transduser dan pada sudut 23o dari sumbu
transdsuser.
Jawab
16
APLIKASI ULTRASONIK
  • APLIKASI INTENSITAS TINGGI
  • Industri
  • Pemrosesan material gas, cairan dan padatan
  • APLIKASI INTENSITAS RENDAH
  • Uji Tak Rusak
  • Evaluasi kualitas bahan
  • Pemeriksaan cacat
  • Instrumentasi dan Kontrol
  • Pengukuran besaran-besaran fisis
  • Pengukuran besaran-besaran proses
  • Pengukuran besaran-besaran kimia

17
ULTRASONIC IN INDUSTRY
APPLICATION DESCRIPTION
Electroplating Agitation of electrolyte Distributing and agitating electrolyte For uniform plating
Implegnation of porous materials (textile, metal ) Increased density, absence of gas inclusion
Deggasing of melts metal, glass Improvement in material density, Refinement of grain structure
Mixing of slurr (pulp) Imrovement in consistency
Agitation of chemical solution (photographic developper Maintaining uniform concentration, Deaeration of liguids
Accelerating chemical reaction Aging of liguors, tanning of hides, extractions
Food treatment Derstroying molds,bacteria, Tenderization,removing loose starch
18
APPLICATION DESCRIPTION
Drying (platic, paper,textile webs ) Turbulence and pressure pattern Causes drying
Cleaning and degreasing Cavitated cleaning solution scrubs Parts immersed in solution
Defoaming and degassing Separation of foam and gas from Liguid,reducing gas and foam content
Foaming of beverages Displacing air by foam in bottles or Container prior to capping
Drilling and abrading Abrasive slurry interposed between Sonically vibrated tool and workpiece
Emulsification,dispersion and homogenization Mixing and homogenizing of liguid, Slurry, cream
Soldering and brazing Displacemen of oxide film to Accomplish bonding without flux
19
APPLICATION DESCRIPTION
Welding metals and plstics Welding similar and dissimilar Metal, soft and rigid plastics
Agglomeration and particle Separating solids from gases or Producing larger particles
Atomization and vaporization Atomizing liguids to provide aerosol, Vaporizing fuel oil
Accelerating chemical reaction Aging of liguors,tanning of hides, extractions
Food treatment Destroying molds, bacteria, Tenderization, removing loose starch
Drying (plastic,paper,textile webs) Turbulence and pressure patten Causes drying
Metal insertion into solid plastic material Application of ultrasonic vibrations to metal insert producing localized softening as insert is pressed into plastic
Metal working Vibrated die or rolling reduces Friction during drawing or rolling, Greater reduction in fewer passes, Reduces grain size
20
ULTRASONIC IN NON DESTRUCTIVE TESTING
INDUSTRY MATERIALS/ EQUIPMENTS DEFECTS
Basic metal Steel, aluminium, iron Magnesium, etc Porosity,inclusions, Center pipe
Metal Fabricators Plate, shett, pipe, tubing, Forgings, extrusions, die block, casting Lamination, seams, inclusion, Bursts, flaking, porosity, concentricity
Aircarft Aircraft engine components, propeller, airframe Components, landing gears Fatique cracks, internal Flaws in materials receved
Automotive Body panel sheets, engine and Transmission parts Lamination, cracks
21
INDUSTRY MATERIALS/ EQUIPMENTS DEFECTS
Automotive Body panel sheets, engine and Transmission part Lamination, cracks
Rubber Tires Ply separation, ply thickness
Plastics Plastics and ceramics Fiberglass-reinforced Porosity, inclusions, cracks Delamination
Railroads Rails, axels and crankshafts in Engine and rolling stock Fatique cracks
Metal stamping Track and wheels Sheet stock Crankshafts, punch press Cracks Laminations, inclusions Fatique cracks
22
INDUSTRY MATERIALS/ EQUIPMENTS DEFECTS
Electric power Turbines and generators Piping Pressure vesselt, penstocks Internal cracks and flaws Seams Weld defects
Chemical and refineries Compressors Vessels and piping Connecting rods Seams, lamination, weld defects
Mining and quarryng Hoist and crusher shafts Fatique crasks
Marine Hull plate Propellers shafts Laminations, weld flaw Cracks, porosity cracks
Metallurgy All metals Physycal constants, Grain size
23
ULTRASONICS IN NON DESTRUCTIVE TESTING
24
ULTRASONIC IN INSTRUMENTATION AND CONTROL
Position Thermometry
Composition Density ,porosity
Anisotropy, texture Pressure
Grain size in metal Elastic properties
Stress and strain Viscosity in fluids
Acoustic emission Level
Imaging , holography Flowmetry
Dynamic force, Vibration, acceleration Location of low- reflectivity interfaces
25
ULTRASONICS IN INSTRUMENTATION AND CONTROL
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