Detection of Weld Defects in Rails using Phased Array Ultrasonic Analysis Software

chemistoddΤεχνίτη Νοημοσύνη και Ρομποτική

6 Νοε 2013 (πριν από 3 χρόνια και 10 μήνες)

52 εμφανίσεις

Detection of Weld Defects in Rails by Ultrasonic
Software

Statistical

and

algorithmic

ultrasonic

software

techniques

are

used

in

the

analysis

of

ultrasonic

images

in

order

to

automatically

detect

potential

weld

defects

using

techniques

such

as

spectral

filtering

and

feature

identification
.

The

analysis

concentrates

on

weld

defects

that

are

internal

and

volumetric

in

rail

welds

because

it

is

highly

relevant

to

the

transport

industry
.

Failure

in

rail

welds

is

an

on
-
going

concern

for

rail

safety
.

A

means

to

detect

flaws

using

phased

array

ultrasonic

techniques

promises

to

minimise

catastrophic

failure

and

provide

paths

to

preventative

maintenance
.

The

use

of

phased

array

analysis

software

to

automatically

detect

defects

in

phased

array

ultrasonic

inspections

provides

a

valuable

preventative

tool

that

will

serve

to

help

maintenance

engineers

to

locate

rail

welds

that

contain

defects,

and

to

provide

a

quantitative

analysis

of

the

severity

of

the

defects,

including

sizing

and

classification

of

the

defect

so

as

to

support

a

decision

to

accept

a

newly

welded

rail

or

to

repair

a

defect

as

past

of

a

maintenance

schedule
.

Keywords: phased array ultrasonic processing software, rail welds, defect detection, phased array, spectral filtering, golden

im
age




Aim of Ultrasonic Software in the Detection of Weld
Defects in Rails

The

purpose

of

Kingston

Computer

Consultancy
’s

(KCC)

involvement

is

to

support

development

of

software

that

is

intuitive

for

inspection

engineers

to

use,

can

profile

different

defect

types

and

can

automatically

detect,

and

ideally

characterise,

potential

defects

in

inspected

rail

welds
.

In

particular,

this

case

study

relates

to

the

extension

of

requirements

to

include

quantitative

analysis

of

the

ultrasonic

based

image

data

of

aluminothermic

rail

welds

through

spectral

filtering

and

golden

image

thresholding
.





Ultrasonic Software Image Processing Challenges: Spectral Analysis, Filtering in Detection of Rail Weld Defects




Conclusions

The

KCC

phased

array

ultrasonic

processing

software

has

developed

statistical

and

algorithmic

methods

to

process

phased

array

data

images

so

that

indications

of

defects

within

rail

welds

may

be

detected

and

effectively

sentenced
.

The

images

have

been

processed

to

reject

background

noise

and

to

enhance

the

regions

where

flaws

may

be

present
.

Engineer

controlled

defect

inspection

assists

in

identifying

the

type

and

severity

of

present

defects,

using

filtering

and

golden

image

background

subtraction

methods

to

detect

weld

defects

in

rails

using

phased

array

ultrasonic

processing

software
.



Acknowledgements

The

material

highlighted

within

this

case

study

pertains

to

work

as

part

of

the

Railect

project

(
http
:
//www
.
railect
.
com/)
.

T h e

R a i l e c t

p r o j e c t

is

funded

by

the

European

Commission

in

order

to

improve

European

transport

and

advance

its

competitiveness

whilst

supporting

research

for

the

benefits

of

Small

and

Medium

Enterprises
.










Detection of Weld Defects in
Rails using Phased Array
Ultrasonic Analysis
Software

For more information on defect detection in rail welds by ultrasonic software see the following websites:


www.kccltd.com


www.railect.com


www.twi.co.uk

Shrinkage defect S11 is shown on the left as an
azimuthal intensity plot. The shrinkage is simulated
using a ceramic insert.

Phased Array Ultrasonic Software
Development

Ultrasonic Software Defect
Analysis of Image

The

first

stage

of

image

analysis

focused

on

separating

areas

of

potential

defect

from

the

image

background

where

there

is

no

anomaly
.


As

the

rail

weld

is

precisely

located

within

the

scan,

the

region

of

interest

(ROI)

can

be

precisely

defined,

and

further

analysis

can

be

tailored

to

process

just

this

region
.

The

phased

array

ultrasonic

instrument

generates

data

using

a

phased

array

probe,

and

this

data

can

be

used

to

produce

linear

or

azimuthal

plots
.

The

requirement

for

further

analysis

of

data

surpassed

that

provided

by

the

phased

array

ultrasonic

instrument,

and

dictated

that

a

custom

designed

software

solution

be

created

for

the

Railect

project
.

Kingston

Computer

Consultancy

Ltd,

as

advisors

to

TWI,

has

assisted

in

creating

a

software

solution

that

allows

for

the

import

of

phased

array

ultrasonic

instrument

data

files,

and

the

generation

of

azimuthal

plots
.

After

the

initial

requirement

of

import

and

display,

the

next

step

was

to

provide

additional

analysis
.

With

the

aim

to

identify

and

locate

two

types

of

defects,

Kingston

Computer

Consultancy

Ltd

researched

methods

used

to

identify

porosity

and

shrinkage

defects,

and

developed

an

averaging

filter

and

a

golden

image

subtraction

filter

to

assist

with

this

t a s k
.

T h e

K C C

s o f t w a r e

h a s

s u c c e s s f u l l y

i d e n t i f i e d

b o t h

d e f e c t

t y p e s

a n d

a u t o m a t i c a l l y

s e n t e n c e d

d e f e c t s

c o r r e c t l y
.

S h r i n k a g e d e f e c t S 1 1 i s s h o w n b e l o w l e f t, t h i s i m a g e
i l l u s t r a t e s t h e u s e o f t h e a v e r a g i n g f i l t e r. B e l o w i s
r e p r e s e n t e d t h e g o l d e n i m a g e s u b t r a c t i o n
o f a p o r o s i t y
d e f e c t.
B o t h f i l t e r s s e p a r a t e b a c k g r o u n d n o i s e f r o m
d e f e c t s a l l o w i n g f o r s u c c e s s f u l d e f e c t r e c o g n i t i o n.


R e a l

s i g n a l s

f r o m

f i e l d

m e a s u r e m e n t s

o f t e n

p r e s e n t

b a c k g r o u n d

n o i s e

t h a t

s i g n i f i c a n t l y

l o w e r s

the

signal
-
to
-
noise

ratio

of

the

received

signal

response

used

in

software

analysis

of

ultrasonic

signals
.

In

such

cases

it

is

advantageous

to

employ

signal

filtering

and

conditioning

so

that

the

maximum

possible

signal

is

recovered

from

the

data

to

detect

defects

in

rail

welds
.

Spectral

representation

of

a

signal

allows

for

noise

statistics

to

be

gathered

and

filtered

from

the

signal

frequency

profile,

thus

reducing

the

noise

component
.

Wave l e t s,

F as t

F our i e r

T r a ns f or m,

and

Wi ene r

f i l t er s

a r e

pr oven

to

be

successful

in

filtering

backscatter

noise

and

electronic

noise

from

A
-
Scans,

and

can

be

included

in

the

analysis

using

KCC

software
.

Below right, the schematic representation of a phased
array probe as it is positioned to perform a scan at the
location of a rail weld, the beam profile is indicated.
The modelling was performed using the
ESBeamTool

software.


Real A
-
Scan results shown in the original form and a post
-
filtered result, using a fast Fourier transform to
gather noise statistics and remove this component from the signal