Non-Destructive Inspection Techniques for Composites

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What fundamental aspect of a composite material do the resin, its chemical composition, and physical properties affect?

Durability (correct)

Processing methods

Shape

Color options

Which type of resins are commonly used for low-cost applications due to their fast processing?

Vinyl Ester Resins

Thermoplastic resins

Polyester Resins (correct)

Epoxy Resins

What is a significant advantage of thermosetting resins in composite material applications?

They are biodegradable

They can cure readily into an insoluble solid (correct)

They are lightweight

They can be easily recycled

In what aircraft components are low smoke producing polyester resins commonly used?

Interior parts Signup and view all the answers

What methods can be used to process fiber-reinforced polyesters according to the text?

Injection molding Signup and view all the answers

What similarities exist between vinyl ester resins and conventional polyester resins according to the text?

Appearance, handling properties, and curing characteristics Signup and view all the answers

What type of defects can visual inspection not find in composites?

Delaminations Signup and view all the answers

Which NDI technique is commonly used to detect delaminations and disbands in composites?

Audible Sonic Testing (Coin Tapping) Signup and view all the answers

What is an indicative response of a well-bonded solid structure during tap testing?

Clear, sharp, ringing sound Signup and view all the answers

What is the frequency range used in Audible Sonic Testing (Coin Tapping)?

10 Hz to 20 Hz Signup and view all the answers

What can produce pitch changes during tap testing that might be interpreted as defects?

Internal structure changes Signup and view all the answers

On what types of structures is tap testing effective for defect detection?

Honeycomb sandwich with thin face sheets Signup and view all the answers

What is the purpose of using lead shields in radiography?

To prevent exposure to X-rays Signup and view all the answers

Why is maintaining a minimum safe distance from the X-ray source essential?

To prevent potential exposure to X-rays Signup and view all the answers

What do thermographic techniques rely on to detect defects?

Differences in thermal conductivity Signup and view all the answers

Why is a heat source used in thermal inspection?

To observe the surface heating effects Signup and view all the answers

Which type of defects can affect the thermal properties observed during thermography?

Water ingress into materials Signup and view all the answers

What can neutron radiography visualize?

Internal characteristics of a sample Signup and view all the answers

What is the main advantage of using radiography as an NDI method?

It allows visualization of internal component details Signup and view all the answers

Why is radiography not ideal for detecting defects like delaminations?

It records changes in total density through the thickness Signup and view all the answers

How does radiography allow inspectors to detect internal anomalies effectively?

By passing X-rays through the assembly and recording absorption onto film Signup and view all the answers

What kind of defects is radiography particularly effective at detecting?

Defects parallel to the X-ray beam's centerline Signup and view all the answers

Why are low-energy X-rays typically used in radiography for composites?

Because composites are nearly transparent to X-rays Signup and view all the answers

What safety concern limits the use of radiography around aircraft?

Risk of radiation exposure to personnel Signup and view all the answers

What are the specific advantages of amorphous thermoplastics noted for?

High temperature capability and good mechanical properties Signup and view all the answers

Which fibers are primarily used in combination with reinforcing fibers in thermoplastics?

Carbon, aramid, and glass Signup and view all the answers

What are the curing stages of thermosetting resins called?

A, B, and C Signup and view all the answers

What type of material is Polyether Ether Ketone (PEEK)?

High-temperature thermoplastic Signup and view all the answers

What is done to prevent further curing of resins in the B stage?

Placing the resin in a freezer at 0°F Signup and view all the answers

What characteristic does PEEK offer in terms of resistance to solvents and proprietary fluids?

Resistance to a wide range of solvents and proprietary fluids Signup and view all the answers