The construction of Formula One cars and the materials used are strictly controlled by regulations to maximise the safety of the cars - Leaving Cert Engineering - Question 2 - 2017

For tough materials:

• Expected behavior includes significant deformation and stretching at the fracture point. The specimen is likely to show a sizable necking region before failure.
• Sketch:

For brittle materials:

• Expected behavior includes sudden fracture with little to no deformation. The specimen typically breaks across the notch without prior elongation.
• Sketch:

To plot the load-extension diagram:

• X-axis: Extension (mm)
• Y-axis: Load (kN)
• Data Points:
  • (0.2 mm, 80 kN)
  • (0.5 mm, 126 kN)
  • (0.8 mm, 146 kN)
  • (1.5 mm, 153 kN)
  • (1.9 mm, 147 kN)
  • (2.0 mm, 152 kN)
  • (2.5 mm, 162 kN)
  • (3.0 mm, 181 kN)
  • (5.6 mm, 174 kN)

The resulting graph will show how the material behaves under loads, with a characteristic curve that can indicate properties such as elastic limit and fracture point.

On the graph:

• Elastic Limit: This point can be identified where the curve begins to deviate from linearity.
• Start of Necking: This occurs at the peak of the load, where the graph starts to level off despite an increase in extension.
• Fracture Point: Presented at the end of the curve, demonstrating the maximum extension reached before failure.

The Ultimate Tensile Strength (UTS) can be calculated using the formula: ext{UTS} = rac{ ext{Max Load}}{ ext{C.S.A}} In this case:

• Maximum Load = 181 kN
• Cross-sectional Area (C.S.A) can be calculated using the diameter of the specimen: ext{C.S.A} = rac{oldsymbol{ ext{π}} imes ( ext{diameter}/2)^2}{1} = rac{oldsymbol{ ext{π}} imes (12 ext{ mm}/2)^2}{1} Finally, we find UTS as follows:
• UTS = 181 kN / (π x (6 mm)^2) = 1.6 kN/mm².

X-ray testing employs x-ray radiation to penetrate materials, producing an internal photographic image of the test piece. This involves:

1. X-Ray Source: Electrons emitted from a heated cathode are aimed at an anode, producing X-rays.
2. Test Object: The X-rays pass through the object, with defects appearing as shades on a film.
3. Image Creation: An image is created on a film that captures any defects within the material.
4. Diagram:
5. Use: This technique is particularly beneficial for inspecting welds.

1. Radiation Exposure: Personnel are at risk of exposure to harmful radiation. Proper shielding and safety protocols must be maintained.
2. Distance Management: It’s crucial to maintain an adequate distance from radiation sources to minimize exposure.