75 Questions
What is the main advantage of the pulse echo method?
It requires access to only one side of the structure
What is the main purpose of using radiographic inspection on composites?
To detect differences in thickness or physical density compared to the surrounding material
Which of the following can thermography be used to detect?
Temperature variations at the surface of a damaged part
What is the main difference between the pulse echo method and the through-transmission method?
The pulse echo method uses a single transducer, while the through-transmission method uses two transducers
Which inspection method can be used to detect entrapped water inside honeycomb core cells?
Radiographic inspection
Which inspection method is best suited for detecting surface cracks in a composite structure?
Radiographic inspection
What is the main purpose of using a reference standard in thermography?
To compare the temperature variations at the surface of the damaged part
Which inspection method is best suited for detecting foreign objects embedded in a composite structure?
Radiographic inspection
What is a core disbond?
Separation between the skin and core of a composite sandwich structure
What can cause a core disbond?
Both poor adhesion and service loading or impact damage
What is a kissing bond?
A type of core disbond that is difficult to detect using NDT methods
Why is it important to avoid disbonds in composite structures?
Both to prevent environmental ingress and maintain structural integrity
Which areas of composite structures are particularly important to avoid disbonds?
End connections and joins
How can cracks in composite structures be detected?
They can be detected using visual inspection and advanced NDI methods
What is the significance of cracks in composite structures?
They allow environmental ingress and can lead to further damage under service loading
When are cracks in composite structures most likely to occur?
Cracks can occur during manufacturing or under service conditions
What is the primary purpose of composite inspection techniques and non-destructive testing (NDT) methods?
To determine the structural integrity of the composite material
Why must a damaged composite structure be thoroughly inspected?
To ensure the damage does not extend beyond the immediately apparent defect
What is the primary method of inspecting aircraft components on a daily basis?
Visual inspection
What is the primary factor that determines whether a damaged composite part can be repaired or must be replaced?
The classification of the damage
What is the primary purpose of the manufacturer's structural repair manual for composite structures?
To outline inspection procedures and damage classification factors
What type of holes can be caused by a lightning strike?
Pinholes
Why are bolted and bonded surface patches usually not recommended for composite repairs?
They cause undesirable aerodynamic changes.
What is the consequence of allowing moisture to get into the core structure of a composite part?
Small delamination
Which repair method involves filling holes or voids by injecting resin into the damaged area?
Resin injections
What is the purpose of resin injections in composite repairs?
To fill holes or voids
Why are pinholes on the skin surface considered significant even though they are not easily detected?
They can expand and cause extensive damage
What determines the exact procedures for repairing various laminated composite structures?
The extent of the damage
What is the primary purpose of visual inspection for composite materials?
To detect surface irregularities and defects like resin-rich areas, delamination, and cracks
Which tools are useful for visual inspection of composite materials?
Strong light and magnifying glass
What is the purpose of tap testing in composite inspection?
To discover if the finished job or repair has a good bond line or has air pockets or inclusions
Which instrumental NDT method is most commonly used on composites for detecting internal damage?
Ultrasonic inspection
In the pulse echo method of ultrasonic inspection, what does the tester do?
Generates ultrasonic pulses, sends them through the part, and receives the return echo
What type of defects can be detected by ultrasonic inspection in composites?
Delaminations, core crush, and other subsurface defects
What is the purpose of a microscope in visual inspection of composites?
To determine if fibers in a cracked surface are broken or if the crack affects the resin only
What is the through-transmission method in ultrasonic inspection?
A method where ultrasonic waves are transmitted through the part and received on the other side
What type of defects can ultrasonic inspection detect in composites?
Internal damage like delaminations
Which tool is useful for tap testing in the inspection of composite structures?
Small tap testing tool
What is a primary application of visual inspection when inspecting composites?
Identifying surface cracks
What is the primary purpose of tap testing in composite inspection?
Finding air pockets or inclusions
What makes ultrasonic inspection particularly effective on composites?
Ability to detect internal damage like delaminations
Why is a small microscope sometimes used during visual inspection of composites?
To determine if fibres are broken in cracked surfaces
What is the main advantage of tap testing in composite inspection?
Effective discovery of bond line quality
What is a core disbond specifically referring to in composite structures?
Separation between the skin and core due to poor adhesion or damage
What is a kissing bond in composite structures?
A type of tight or weak bond that is difficult to detect
How does cracking impact the integrity of composite structures?
It allows for environmental ingress and damage under service loading
Why may cracks in composite structures require more advanced methods of non-destructive inspection (NDI)?
They are often invisible to the naked eye
What is the significance of avoiding disbonds in joins such as end connections in composite structures?
To maintain structural integrity and prevent potential failures
Why should cracks in composite structures be thoroughly inspected?
To determine their extent and impact on structural integrity
What role does non-destructive inspection (NDI) play in detecting defects in composite structures?
It helps identify defects without causing damage to the structure
When might cracks in composite structures be associated with the final stages of in-service failure?
When they propagate and weaken the structure
What is the potential consequence of pinholes on the skin surface of a composite structure?
Leading to extensive damage
Why are bolted and bonded surface patches typically not recommended for composite repairs?
They cause undesirable aerodynamic changes
Which method involves injecting resin into the hole of a damaged area using a needle and syringe for composite repair?
Resin injections
What is the main drawback of moisture intrusion into the core structure of a composite part?
Causing small delamination to grow into a larger one
Why are pinholes on the skin surface of a composite structure considered significant despite being hard to detect?
They could lead to extensive damage
What aspect determines the procedures for repairing various laminated composite structures?
The severity of the initial damage
In which scenario can resin injection repairs be commonly applied?
On parts with holes or voids
What type of patches do not restore the strength characteristics of the original composite structure?
Bolted metal patches
What is the most desirable type of permanent repair for a composite structure?
Lamination of new repair plies in the damaged area
What is the primary disadvantage of potted repairs?
They do not provide as much strength as a core material plug
Which step comes first in the composite damage assessment and repair process?
Find and clean the damaged area
What is a potential consequence of filling a hole in a composite structure with a resin-and-filler mixture?
It adds weight and decreases flexibility
Which step follows the fabrication of the composite repair?
Prepare the repair site
What is the purpose of cleaning up the repair site after installing a composite repair?
To prevent contamination during the inspection process
Which step in the composite repair process involves non-destructive inspection (NDI)?
Inspecting the repair for structural integrity
What is the final step in the composite damage assessment and repair process?
Document the repair
What type of damage to an aircraft structure is considered 'non-repairable' according to the text?
Damage that cannot be repaired and requires the component to be replaced
What does the presence of areas of condensation on an aircraft structure indicate according to the text?
Water ingress into the structure
What is a cosmetic defect in the context of aircraft structures as described in the text?
A defect on the outer surface skin without damage to the structural reinforcing fibers
When is tap testing commonly used in composite inspection according to the text?
Detecting surface cracks
Why are pinholes on the skin surface of composite structures significant according to the text?
They can cause stress concentrations
What does thermography primarily help detect in aircraft structures according to the text?
Areas of condensation indicating water ingress
Which type of damage would most likely require component replacement according to the text?
Damage to the structure or component that cannot be repaired
What type of defect does cosmetic defect refer to in aircraft structures as mentioned in the text?
A defect on the outer surface skin with no structural reinforcing fiber damage
Test your knowledge on composite inspection techniques and non-destructive testing (NDT) methods used to determine the airworthiness of structures. Learn about the transfer of metal inspection methods to composite applications and the importance of ongoing inspection intervals.
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