Acoustic Emission Basics by Boris Muravin

Acoustic Emission Method History. Fundamentals. Applications.

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Outline

Definition of Acoustic Emission Phenomenon ,[object Object]

Who was the First? ,[object Object],He was the First who used AE as a forecasting tool

Early History of AE ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

History of First AE Experiments ,[object Object],[object Object],[object Object],[object Object]

History of First AE Experiments ,[object Object],[object Object],[object Object]

Start of Industrial Application of AE ,[object Object],[object Object],[object Object],[object Object],[object Object]

Acoustic Emission Instrumentation ,[object Object],[object Object],[object Object],[object Object],[object Object],Sensors Main amplifiers with filters Measurement Circuitry Preamplifiers with filters Computer Acquisition software Data storage Data presentation

AE Sensors ,[object Object],[object Object],[object Object],[object Object],Regular piezoelectric sensor Integral piezoelectric sensor Preamplifier 60 dB

Sensors Characteristics ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],AE signal of lead break and corresponding Power spectrum.

Installation of Sensors on Structure ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Sensor attached with magnet Pb blanket in nuclear applications Waveguide Rolling sensor produces by PAC

Methods of AE Sensors Calibration ,[object Object],[object Object],[object Object],[object Object]

AE Data Acquisition Devices ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Principals of AE Data Measurement and Analysis

Threshold and Hit Definition Time (HDT) Threshold and HDT are parameters that used for detection AE signals in traditional AE devices. HDT: Enables the system to determine the end of a hit, close out the measurement process and store the measured attributes of the signal. Hit 1 Hit 1 Hit 2 Short HDT Long HDT Threshold Long HDT Short HDT

Burst and Continuous AE Signals Burst AE is a qualitative description of the discrete signal's related to individual emission events occurring within the material. Continuous AE is a qualitative description of the sustained signal produced by time-overlapping signals. “ AE Testing Fundamentals, Equipment, Applications” , H. Vallen

AE Parameters ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Background Noise ,[object Object],Time Amplitude Floating threshold

Attenuation, Dispersion, Diffraction and Scattering Phenomena ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Source Location Concepts ,[object Object],[object Object],[object Object]

Linear Location ,[object Object],[object Object],Material Effective velocity in a thin rod [m/s] Shear [m/s] Longitudinal [m/s] Brass 3480 2029 4280 Steel 347 5000 3089 5739 Aluminum 5000 3129 6319

Two Dimensional Source Location ,[object Object],Sensor 1 Sensor 2 Sensor 1 Z D R2 R1 R1 R2 R3 Sensor 2 Sensor 3 ,[object Object],R3

Cross-correlation based Location Ch 1 Ch 2 Cross-correlation method is typically applied for location of continuous AE signals. Δ t Normalized cross-correlation function Δ t Cross-correlation function

Zone Location ,[object Object],[object Object],[object Object],[object Object]

Sources of AE in Metals More then 80% of energy expended on fracture in common industrial metals goes to development of plastic deformation.

Plastic Deformation ,[object Object],[object Object],[object Object],Edge dislocation motion ,[object Object],(1) Materials Science and Engineering an Introduction, William D. Callister, Jr. Edge dislocation Screw dislocation Mixed dislocation 1 2 3 4 5 Physical Process Activation Energy (eV) Dislocation glide 1.2 Formation of dislocation 8-10

Plastic Zone at the Crack Tip ,[object Object],[object Object],[object Object],[object Object],Fracture Mechanics Fundamentals and Applications, Second Edition, T.L Anderson.

Factors that Tend to Increase or Decrease the Amplitude of AE Nondestructive Testing Handbook, volume 6 “Acoustic Emission Testing”, Third Edition, ASNT.

Relationship between AE and Fracture Mechanics Parameters and AE Effects

Models of AE in Metals ,[object Object],[object Object],[object Object],[object Object],(3) Strains at the crack tip vary at where r is the radial distance from the crack tip. (4) ,[object Object]

Fatigue Crack Model ,[object Object],[object Object]

AE Effects ,[object Object],[object Object],[object Object],Kaiser effect (BCB) Felicity effect (DEF)

AE Inspection of Pressure Vessels

AE Testing of Pressure Vessels (1) Nondestructive Testing Handbook, volume 6 “Acoustic Emission Testing”, Third Edition, ASNT. Pressure Policy for a New Vessel (1) Example of Transducers Distribution on Vessel's Surface (1) Typical Results Representation of Acoustic Emission Testing (1)

Example of Pressure Vessel Evaluation ,[object Object],(1) Nondestructive Testing Handbook, volume 6 “Acoustic Emission Testing”, Third Edition, ASNT. The numbers on plot correspond to sensors numbers. (1) N – number of hits, S 0i – the signal strength of the i-th event, J – specific number of events K=0.8J for J≤N≤1000 and K=N-200 for N>1000 ,[object Object]

AE Standards ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

AE Standards ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],AE Standards

More educational materials on Acoustic Emission available at www.muravin.com

Acoustic Emission Basics by Boris Muravin

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Acoustic Emission Basics by Boris Muravin