Task (1)

You work as a material engineer at an aircraft development,manufacturing and maintenance company in the MENA region. Recently,the manufactured airplanes have been experiencing crashes after acouple of years in service. You have been assigned as a member inthe investigation team to identify the main cause of thecrashes.

                           

1. The shape of the designed windows of the manufactured planes issquare. The investigation team suggested that this design might bethe main cause of the crashes. You must provide a possibleexplanation of the investigation conclusion from an engineeringpoint of view.

1. Write the properties that should be considered whendesigning and manufacturing the coroners of thewindows from an engineering point of view.

1. You have been given a sample of a malfunctioned airplane wing,which is made of aluminium. The company offered you an access to atensile testing equipment and magnetic particles inspectionequipment to investigate the malfunctioning behaviour. The resultsof your experiment were as follows:

Load (KN)	Extension (mm)
13	0.2
29	0.4
56	0.7
70	0.9
95	1.5
110	2.5
132	5
147	8.5
145	10
130	12

Table 1: Tensile Testing Results (Load Extension)

1. Given that the length of the sample is 90 mm and the diameterof it is 7 mm.
   1. Draw the stress stain diagram.
   2. Find the yield stress (in KN/mm²).
   3. Find the ultimate tensile stress (in KN/mm²).
   4. At a point on the proportional section, calculate the modulusof Elasticity (Young’s modulus).

Hint: when calculating theElasticity, use the stress strain numbers, not the forcenumbers