Assignment overview: Carbon fibre reinforced polymers (CFRP have been used extensively in aerospace applications due to their excellent strength to weight and stiffness to weight properties.

Recently there has been a sharp increase in the use of carbonFfibre reinforced polymers in non aerospace structural applications to replace metals. One example is the development of a one piece CFRP wheel for use in automotive applications. An important aspect of introducing any new structural component is the confidence that there are no internal (non visible on the surface manufacturing defects that could affect its useable life. Defects could lead to a reduction in properties such as stiffness or strength, as well as being a precursor for failure modes such as fatigue. Since some of these automotive structures are more complex and a thicker geometry structure than most aerospace CFRP components, manufacturers may be unsure as to whether they can use similar NDT techniques as the aerospace industry.

You are required to review and understand nonFdestructive testing (NDT technique (or techniques that would be practical for ensuring  that the CFRP components made for automotive applications did not contain any of the three internal defect types listed below. Assignment submissions only need address the 4 questions stated.

Defect 1 - pores greater than 4 mm in diameter

Defect 2 - Resin rich areas greater than 5 mm in diameter

Defect 3 - Fibre waviness

Part 1 

For each question, ensure that you use peer-reviewed references to support your statements.

1. In your own words, briefly explain what the three defect types listed above are. How might each of them affect the structural performance or usage life of a component if present?

2. Identify one commonly used NDT technique used for damage examination of CFRP components in the aerospace industry. Explain how the NDT technique works, what type of damage or defects that it is used to identify, and how it identifies the damage or defect.

Part 2

For each question, ensure that you use peer - reviewed references to support your statements.

Resubmit questions 1 and 2 taking into account feedback

3. For each of the three defect types, identify at least 2 possible NDT techniques that could be used to locate them in a CFRP wheels. Briefly explain how each technique works, and how it identifies the defect. For each NDT technique you identify, find evidence from an experimentally@based peer@reviewed journal publication that a defect of the specified size/type can be reliably identified using that specific NDT technique.

4. It is probable during the service life of an automobile that a minor impact could cause internal damage (cracks or delamination's within a carbonFfibre composite component, and that as a result the stiffness or loadFcarrying capacity is reduced. Identify what you believe would be the cheapest and easiest method that could be used to assess whether the component was still usable. To answer this question properly, you will most likely need to briefly explain possible methods that could be used, and then adequately justify why the one you have chosen is the best choice. You can assume the component can be detached from the vehicle for assessment if you need too (any other assumptions necessary to answer the questions should be clearly stated.