NDE Karakterizacija Materijala FSB

8/9/2019 NDE Karakterizacija Materijala FSB

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non-destructive testing NDT

non-destructive examination NDE

non-destructive evaluation NDE

non-destructive inspection NDI

zerstrungs-freie prfung ZfP

...strani nazivi:

nerazorna ispitivanja (HZN, TO 135)

kontrola bez razaranja

ispitivanja bez razaranja

defektoskopija

...HR nazivi:

NDE karakterizacija materijala

ZAVOD ZA KVALITETU

KATEDRA ZA

NERAZORNA ISPITIVANJA

Prof.dr.sc. Damir Markui

Nerazorna ispitivanja

U svrhu pronalaenja nepravilnosti

su vrlo znaajna za praenje kvalitete

u proizvodnjizavarivanje, odljevci, otkivci,

strojne i toplinske obradbe, ...

i posebno tijekom

eksploatacijepetrokemijska i energetskapostrojenja, nuklearna

postrojenja, pomorski objekti,

transport,

posude pod tlakom, ...

volumnih i

planarnih,

. nastalih uslijed tehnolokih ili eksploatacijskih uvjeta.


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Metode i tehnike nerazornih ispitivanja

a obzirom na specifinosti naina provedbe ispitivanja na

TEHNIKE nerazornih ispitivanja

Obzirom na fizikalne principe/naela, nerazornaispitivanja dijelimo na

METODE nerazornih ispitivanja,

PRINCIP ispitna struktura METODA TEHNIKE

elektromagnet-

ski valoviX i zraenje

RT

radiografska

(radijacijska)

radiografija,

radioskopija,

gamagrafija, XRD, XRF

vidljivi dio

spektra

VT

vizualnadirektna, RVI

IR valoviIR

termografska

termovizija,

lock-in termografija

mikrovaloviGPR

radarska

niskofrekventna

polja

ET

(EC, vrtlone struje)RFEC, ACPD, ACFM, ..

magnetsko poljeMT

magnetska

magnetskim esticama,

MFL, Barkhausen

elastini valovi ultrazvuni valoviUT

ultrazvuna

tehnike odjeka (PE),

difrakcije (TOFD), ...

akustiki valoviAC, AE

akustika

akustika emisija,

Impact Echo (IE)

kontaktpenetrant

(kapilarni efekt)

PT

penetrantska

ovisno o vrsti

penetranta...

inertni plin

(propusnost)

LT

ispitivanje propusnostivacuum, helij


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Metode i tehnike nerazornih ispitivanja

Ovisno o primijenjenom fizikalnom principu i ispitnim

parametrima (npr. osjetljivost, razluivost) moe se govoriti

Stoga se nerazorna ispitivanja primjenjuju u cilju

i o odzivu materijala (strukture).

pronalaenja nepravilnosti (pogreaka) i

karakterizacije materijala

Detekcija nepravilnosti temelji se na

odreenom odzivu od nepravilnosti.

Pobuda odzivi

ispitivana

cjelina

izvorprobe analizatorprobe

proba

okolina

PRINCIP

Razina odziva od nepravilnosti i

od materijala.


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Ispitivanje ultrazvukom (UT) - osnove

Propagacija impulsa kroz medij - interakcija

brzina propagacije

ultrazvunog impulsa

relevantna (akustika) svojstva medija

akustika impedancija Z = v

pojave na granici dva (akustiki razliita) sredstva

Snellov zakon loma

konverzija

koeficijentirefleksije i transmisije

(Ri T)

Ispitivanje ultrazvukom (UT) - osnove

Propagacija impulsa kroz medij - interakcija

konvencionalna granica detekcije u ispitnom materijalu proizlazi

iz frekvencije odabrane sonde i brzine propagacije UZ impulsa:

v = * f

detektibilnost: /2 = d npr. d = 0,3 mm

f: od 2 do 10 MHz (1-20 MHz) v: od 2000 do 6500 m/s

slabljenje energije impulsa guenje

koef. priguenja

gubici uslijed: apsorpcije, rasprenja,

geometrije UZ polja

iznos ovisi o odabranoj frekv.,

odnosno o odnosu

veliine zrna d i (valne duljine)


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UT - frekvencijske karakteristike

UT - frekvencijska analiza


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UT - primjeri karakterizacije

Karakterizacija amplitudnih odziva - priguenje


Karakterizacija materijala u kontaktu


9/12

UT - primjeri karakterizacijehttp://www.olympus-ims.com/en/ndt-application/183-id.209715263.html

Measuring Nodularity in Cast Iron

Application: Measuring degree of nodularity

in cast iron, or distinguishing nodular iron from

gray iron.

Problem: Carbon in the form of graphite is

often used as an additive in the production of

cast iron, amounting to 2 to 4 percent by

weight or 6 to 10 percent by volume in typical

castings. The microstructure of graphite within

cast iron has major effects on the casting's

mechanical properties. When graphite

arranges itself as thin flakes the result is grayiron, which is hard and brittle. When graphite

takes the form of spherical nodules the result

is nodular iron, which is soft and malleable.

UT - primjeri karakterizacijehttp://www.olympus-ims.com/en/ndt-application/183-id.209715270.html

Elastic Modulus Measurement

Application: Measurement on Young's

Modulus and Shear Modulus of Elasticity, and

Poisson's ratio, in nondispersive isotropicengineering materials.

Problem: Young's Modulus of Elasticity is

defined as the ratio of stress (force per unit

area) to corresponding strain (deformation) in

a material under tension or compression.

Shear Modulus of Elasticity is similar to the

ratio of stress to strain in a material subjected

to shear stress.

Poisson's Ratio is the ratio of transverse strain

to corresponding axial strain on a materialstressed along one axis.


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UT - primjeri karakterizacijehttp://www.mendeley.com/research/dependence-ultrasonic-velocity-

porosity-pore-shape-sintered-materials/#

Dependence of ultrasonic velocity on porosity

and pore shape in sintered materials Abstract:A new approach to predict the longitudinal and

transverse ultrasonic velocities in porous materials is presented. The

model is based on a previously derived Young's modulus-porosity

correlation assuming spheroidal geometry of the pores. It is also

assumed that the Poisson's ratio of porous materials does not change

significantly with porosity. The longitudinal and transverse ultrasonic

velocities are given as functions of the Young's modulus, Poisson's

ratio, density of the pore-free material and of the porosity and axial

ratio (z/x) of the spheroidal pores. Experimental data drawn from the

literature on different porous sintered materials including SiC, Al2O3,

YBa2Cu3O7-x, porcelain, sintered iron, Si3N4, and sintered tungsten,

were used to verify the model. A strong relationship between pore

shape and the slope of the ultrasonic velocity-porosity curve was

confirmed. In general, the calculated values are in fairly goodagreement with the experimental data. When the actual shape (axial

ratio) of the pores was known, the approach was shown to predict the

experimental data better than a similar model derived by Phani. It is

suggested that the present approach, coupled with the measurement

of the ultrasonic velocity, may constitute a simple nondestructive

technique to gain knowledge of the morphology of the porosity in

sintered materials.


11/12


Mjerenje tvrdoe

http://www.ndt.net/ndtaz/content.php?id=178

Ultrasound is used for the measuring of hardness

or elastic material properties under loads by

the ultrasonic contact-impedance (UCI)method, in which a rod-shaped resonator , one

end holding an indentation body, is pressed

against a test specimen with a given test force,

so that the indentation body penetrates the

specimen, and the resulting change of df in the

frequency f of the resonator is measured. The

probe usually contains a Vickers diamond

(136 pyramid) and due to conversion scales

the reading can be performed in HV, HB, HRC,

HRB and HS.


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Scanning Acoustic Microscope (SAM)

http://www.sv.vt.edu/comp_sim/sam/sam.html

Our goal in this study is to investigate how a SAM can be used to evaluate elasticproperty gradients that exist near a fiber-matrix interface. Unlike images from

a reflecting microscope, a SAM image can highlight differences in elastic

properties. For example look at this SAM image of a [0/90] glass/epoxy fiber-

reinforced composite laminate [Briggs, 85]..


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NDE Karakterizacija Materijala FSB