Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

M&M > Non-Destructive Techniques > Flashcards

Non-Destructive Techniques Flashcards

1
Q

Define infrastructure resilience

A

The capacity of infrastructure to mitigate, adapt, or positively respond to chronic and acute stresses, transforming in ways that restore, maintain and even improve their essential functions

Simplified: robustness of a structure to withstand hazards

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Give an example of resilient infrastructure

A

Tokyo Underground Floodwater Tunnels

Channels excess water to river

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Define Non-Destructive Techniques

A

Process of inspecting, testing, or evaluating materials, components or assemblies for discontinuities/differences in characteristics, without destroying the serviceability of the part/system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are NDT methods used for?

A

To locate the exact location and characteristics of damage.

Usually done after continuous monitoring detects the general location of damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Give an overview of visual inspection methods

A

Can be by direct viewing, using line-of-sight vision, or using optimal instruments.

Used to detect corrosion, misalignment of parts, physical damage and cracks.

Examples include underbridge units (image), elevating platforms and truck cranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the advantages of visual inspection methods?

A
  • Easy to apply
  • Quick
  • Low-cost
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Give an overview of the UAV (unmanned aerial vehicles) inspection method

A

UAVs are autonomously/semi-autonomously controlled aircrafts that can be equipped with cameras.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the advantages of UAV methods?

A
  • Only need an operator on the ground (safety)
  • Use low cost technologies whilst reaching high level of complexity
  • Capability of fast real time data acquisition and the storage of all relevant flight data
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the limitations of UAV methods?

A
  • Small payload; only small format/light cameras can be used for photos and videos
  • Low weight makes flight sensitive to harsh weather
  • Restrictions/permissions needed to be used in some areas (e.g. around electrified railway)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the principles behind acoustic inspection methods?

A

Materials ‘talk’ when they are in trouble.

Acoustic emission equipment can ‘listen’ to the sounds of cracks growing, fibres breaking, and more

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Name the different types of acoustic methods

A
  • Chain Drag (mechanical)
  • Impact Echo (mechanical)
  • Ultrasonic Pulse Velocity
  • Ultrasonic Pulse Echo
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the chain drag method used for?

A

Identifying cracks, delaminations and other surface defects, in combination with visual inspection

Effective in locating shallow delaminations on uncovered decks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the limitations of the chain drag method?

A
  • Requires lane closures
  • Labour intensive
  • Dependent on user and traffic volume (noise)
  • Can’t be used to locate delaminations in the concrete below bituminous material
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Give an overview of the Impact Echo method

What materials is it used to test?

A

Uses impact-generated stress (sound) waves, which propagate through the material and are reflected by internal flaws and external surfaces

Used to test concrete and masonry structures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Give example uses of the Impact Echo method

A
  • Measuring the thickness of new highway pavements and concrete slabs
  • Bridge deck delamination detection
  • Finding the location and extent of flaws, including cracks, delaminations, voids in plain, reinforced, and PT concrete structures
  • Determining thickness/locating cracks and other defects in masonry structures (where the brick or block units are bonded together with mortar)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the advantages of the Impact Echo Method?

A
  • Not user intensive
  • Provides data regarding top and bottom surface delamination
  • Cost-effective; saves lots of money on repair/retrofit costs on bridges, retaining walls, and other large structures
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the disadvantages of the Impact Echo Method?

A
  • Requires lane closures
  • Interpretation of results requires experience
18
Q

Give an overview of (general) ultrasonic testing

A
  • Ultra-high frequency sound introduced
  • If sound hits a material with a different acoustic impedance, some of it is reflected (and presented on display)
  • Distance to the reflector determined by knowing the speed of the sound and the time taken for it to return
19
Q

What are the most common sound frequencies used in UT?

How do lower frequencies perform with respect to sensitivity and penetrating power?

A

Between 1.0 and 10.0 MHz

Lower frequencies have greater penetrating power but less sensitivity (ability to ‘see’ small indications)

20
Q

Give an overview of the Ultrasonic Pulse Velocity Method

A
  • Ultrasonic pulse of 50 to 54kHz produced by electro-acoustical transducer
  • Measures travel time T of the pulse; with path length L, finds the pulse velocity (V = L/T)
  • The material is held in contact with one surface of the concrete member under test, and receives the same pulse by a similar transducer in contact at the other end
  • Ultrasonic pulse velocity depends on the density and elastic material properties
21
Q

What is the Ultrasonic Pulse Velocity method used for?

A
  • Qualitative assessment of strength of concrete/its gradation in different locations
  • Any discontinuity in the cross-section (cracks, cover concrete delamination etc)
  • Depth of surface cracks
22
Q

What pulse velocity gives an excellent concrete quality grade?

What is done if the results indicate the concrete quality is ‘doubtful’

A

Above 4.5 km/second

If doubtfoul (below 3.0), a core test is done

23
Q

What are the limitations of the Ultrasonic Pulse Velocity method?

A
  • High operator skill needed
  • Defects may be masked in certain materials (e.g. austenitic steel; large grain size found in welds can cause attenuation)
  • Misreading of signals can result in unnecessary repairs
24
Q

Give an overview of the Ultrasonic Pulse Echo method

What materials is it used on?

A
  • Very commonly used for inspecting steel structures
  • Mechanical waves (ultrasound) generated by a piezo-magnetically excited element at a frequency between 2 to 5 MHz
  • Can detect cracks and determine crack depth with a high degree of accuracy
25
Q

What are the uses of the Ultrasonic Pulse Echo method?

A
  • Determining cracks/crack depth
  • Identification of internal defects in welds, metal, plastics, ceramics, glass
  • Examination of plates, castings and forgings
26
Q

What are the limitations of the Ultrasonic Pulse Echo method?

A
  • UT testing has a dead zone; near surface cracks will be missed in thin steel plates
  • Highly skilled operators required
  • Surface must be accessible
  • Requires a coupling medium to promote the transfer of sound energy into specimen
  • Difficult to inspect rough/irregular/non-homogenous, and cast iron/other coarse grained materials
27
Q

List the different types of electromagnetic testing methods

A
  • Ground Penetrating Radar (GPR)
  • Magnetic Tomography Technology
  • Covermeter
28
Q

How does the GPR method work?

A
  • Polarised pulses of EM energy transmitted into ground
  • Energy that is reflected back to the surface, due to a contrast in dielectric properties between adjacent materials, is recorded
  • GPR signal responds to variations in electrical properties (dielectric constant, conductivity) of subsurface materials; function of material type, moisture content, pore fluid type
  • Subsurface structures mapped by measuring the amplitude and travel time of reflected energy
29
Q

In GPR testing, what does the reflection of a material with high relativity permittivity result in?

A

This causes a phase shift of reflected signal of 180 degrees.

30
Q

What are GPR methods used for?

A
  • Very effective for investigating the integrity of concrete structures
  • Used in masonry arches (difficult in general to find methods for masonry)
  • Detection of reinforcement and tendon ducts, dowels and anchors
  • Voids, cracks and delaminations in concrete and masonry
  • Thickness measurements of concrete structures (that are only accessible from one side)
  • Locating internal steelwork in concrete (e.g. rebars)
  • Can be used as part of a quality assurance system; reducing high maintenance costs
31
Q

What are the limitations of GPR methods?

A
  • Requires lane closures
  • Interpretation of results requires experience
  • Size limitations (e.g. max thickness that can be measured is 0.5m)
  • Can’t investigate fresh and setting concrete (high moisture content causes scattering effects due to absorption of EM waves)
32
Q

What is the name of the Magnetic Tomography Technology device that can be used on fresh concrete, and how does it work?

A
  • MIT Scan-2
  • Locates dowel bars placed for all jointed concrete pavements
  • In one scan, location and alignment of all dowels along the entire joint determined
  • Extremely accurate (multiple sensors and innovative data interpretation software)
33
Q

Give an overview of how Cover Meter devices work

A

The device emits an EM pulse and detects the magnetic field induced in metal objects

34
Q

What are the uses of Cover Meter devices?

A
  • Mainly used for locating reinforcement in concrete structures and determining the depth of concrete cover
  • Making drawings for old buildings
  • Drilling and core cutting
  • Corrosion analysis
35
Q

What are the limitations of Cover Meter (and MIT Scan-2) devices?

A
  • Older devices are only capable of detecting metals close to the concrete surface
  • Presence of other metal affects measurement results
  • MIT Scan-2 requires the diameter and length of the bars to be known, and that a calibration is performed using the specific dowel bar
36
Q

Name a thermal NDT method, and what is it used for?

A

Infrared Thermography (IRT)

Used for inspection of bridge decks with a vehicle based system

37
Q

Give an overview of the Infrared Thermography (IRT) method

A
  • Vehicle based system that utilises an advanced thermographic camera (and advanced data acquisition/image processing software) to give accurate detection rates in the location and size of deteriorated concrete areas
  • Natural cooling and heating of deck produces temperature differentials at delamination
38
Q

What are the advantages of the Infrared Thermography (IRT) method?

A
  • Cost effective
  • Penetradar has improved upon current methods (of IRT inspection) using advances in camera technology
  • Streamlined data collection and enhanced analysis
39
Q

What are the limitations of the Infrared Thermography (IRT) method?

A
  • The results are affected by sun exposure and time of day
  • Depth of delamination
  • Interpretation of results requires experience
40
Q

List three types of electrochemical inspection methods

A
  • Half Cell Potential
  • Electrical Resistivity
  • Polarisation Resistance
41
Q

Give an overview of the Half Cell Potential inspection methods

A
  • Used to determine the probability of corrosion within the rebar in RC structures
  • Measures the potential difference between reference half cell and reinforcing
  • Gives an indirect indication of delamination
42
Q

What are the limitations of the Half Cell Potential (and general electrochemical) inspection methods?

A
  • Requires lane closures
  • Somewhat labour intensive
  • Interpretation of results require experience
  • Requires drilling in deck to expose reinforcement
  • Doesn’t provide good data regarding the corrosion state of embedded reinforcement

M&M (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions