ADVANCED NDT METHODS

THERMOGRAPHY

Infrared thermography is equipment or method, which detects infrared energy emitted from object, converts it to temperature, and displays image of temperature distribution

CHARACTERISTICS OF INFRARED THERMOGRAPHY EQUIPMENT

It captures as a temperature distribution on a surface,and it can display as a visible information.

Temperature can be measured from a distance without contacting an object.

Temperature can be measured in real time.

ADVANTAGES OF IR SYSTM

• Relative comparison of distribution of surface temperature can be made over a wide area.

• Temperature can be measured easily for a moving object or an object which is dangerous to get close to.

• Temperature of small object can be measured without confusing the temperature.

• Temperature of food, medicine or chemicals can be measured in a sanitary fashion.

• Temperature of an object with drastic temperature change or a phenomenon during a short period of time can be measured.

CHARACTERISTICS OF INFRARED SYSTEM

• It is invisible since its wavelength is longer than visible light. Not connected with brightness or darkness of visible light

• It is emitted naturally from any object of which temperature is absolute zero(0K) or higher. 　 Hence can be applied to any field

• It is a kind of light (electromagnetic wave) 　 It can be transmitted through vacuum. There is a correlation between infrared energy and temperature of an object. 　 　 Therefore, it can be used to measure the temperature of an object

PRINCIPLE

Camera Element

The　sensitivity　of　camera:

240　x　120

320　x240,

640x320　pixels

THERMOGRAPHY IMAGE

Principle of AET

Acoustic Emission Technology

powerful method for examining the behavior of materials deforming under stress. Acoustic Emission may be defined as a transient elastic wave generated by the rapid release of energy within a material. Small-scale damage is detectable long before failure, so AE can be used as a non-destructive technique to find defects during structural proof tests and plant operation.

FAILURE MODE

Crack propagation

Yielding

Fatigue

Corrosion, Stress corrosion

Creep

Fiber fracture, delamination

Continuous monitoring (metallic structures, mines, etc.) Periodic testing (pressure vessels, pipelines, bridges, cables) Loose Part Detection

Leak Detection

Application of AEMonitoring structures:

Application of AE Special applications

Petrochemical and chemical: storage tanks, reactor vessels, offshore platforms, drill pipe, pipelines, valves, hydro-treaters Electric utilities: nuclear reactor vessels, piping, steam generators, ceramic insulators, transformers, aerial devices Aircraft and aerospace: fatigue cracks, corrosion, composite structures, etc. Electronics: loose particles in electronic components, bonding, substrate cracking.

SensorsPiezo electric type AE sensors sense motion in the low ultrasonic frequency range (10 kHz - 2000 kHz).  Motions as small as 10-12 inches can be detected.  Can hear the breaking of a single grain in a metal, a single fiber in a fiber-reinforced composite, and a tiny gas bubble from a pinhole leak as it arrives at the liquid surface.  By detecting sources as small as above or as large as brittle crack advance, the structural health is monitored

AE Signal

AE Equipment

Location of Acoustic Emission Sources

Real　time　analysis　Can　be　located　at　the　surface　at　a　distance　from　the　sourve　of　soundExact　location　can　be　detected　by　traingulation　method　by　calculating　the　time　taken　for　individual　wave　to　arrival　at　each　sensor　　　For　location　in　one　dimension　–　two　sendors　are　requiredFor　location　in　two　dimension　three　sesnors　are　requiredFor　location　in　three　dimension,　four　sensors　are　requiredRelatively　large　sructures　can　be　analysed　by　multiple　sensorsInsulation　need　not　be　removed　in　vessels　　

Application of AE PULP AND PAPER INDUSTRY

cracks　in　rotating　pressure　vessels,　such　as　steam-heated　Yankee　and　paper　machine　dryers

in　rotating　equipment,　such　as　felt　rolls,　reel　spools,　calendar　rolls,　and　suction　rolls

　machine　structural　components,　such　as　swing　arms　

delamination　of　bonded　materials,　including　thermal　spray　metal　coatings　and　rubber　roll　covers　

hydrostatic　testing　of　pressure　vessels　in　fitness　for　service　examinations

Application of AE LEAK DETECTION

Acoustic　energy　is　transmitted　through　the　fluid,　through　air　or　the　structure　to　a　piezo　electric　sensor.　detects　the　AE　signal　that　is　generated　from　the　turbulent　or　cavitational　flow　through　a　crack,　valve,　seal　or　orificemonitoring　of　pipelines　in　utility　and　petrochemical　plants　

leak　detection　in　boilers,　vessels,　and　through　valves.　

Multiple　sensors　controlled　in　one　machine

Can　operate　as　a　stand　alone　mode

Application of AE VESSEL INSPECTION

Vessel　inspection　for　metal　and　FRP　vessels　and　spheresSensors　are　placed　on　the　vessels　in　arrays　to　monitor　the　entire　pressure　boundary.　The　vessel　is　then　subjected　to　pressures　typically　10　percent　above　previous　operating　levels　(well　below　the　vessel　pressure　rating)　with　the　test　pressures　being　subjected　in　a　pressure　rise-hold-rise-hold　fashion　to　peak　stress,　while　monitoring　the　AE　activity　during　each　of　these　pressurization　segmentsAE　examination　of　vessels　is　the　most　sensitive　and　cost-effective　method　for　vessel　inspection　in　the　world　today　and　adheres　to　standards　set　by　ASTM　and　the　American　Society　of　Mechanical　Engineers　

Application of AE Weld Analysis

Weld　Quality　Analysis　and　Weld　Control,　 resistance　spot　welding　(alternating　current　and　direct　current),　 metal-inert　gas/tungsten-inert　gas　welding,　 electron　beam　welding,　 laser　welding,　 friction　welding.Able　to　detect　 oxidation　burn-off,　 nugget　formation,　 hot　cracking,　 expulsion　　 post　weld　cracking.　

Application of AE Crack Detection

One　of　the　oldest　and　most　successful　applications　of　acoustic　emission　has　been　in　manufacturing,

with　the　detection　of　cracking　in　various　materials　during　 bonding, forming　　 pressing　operations.　

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Pre-amplifier

AE　Sensor

Amplifier

Controller

AE Sensor

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