Experiemnet on Properties of Materials

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Title of experiment: Structure properties of materials

Demonstrator: Tim Lee

Academic leader: Dr. Ballal

Name of student: Kwesi Nkrumah

Aim
To calculate a range of different properties (steel, aluminium alloy, pure aluminium .PMMA, timber and nylon) and measure deflection at failure, energy stored at failure and the young modulus for each of the respective materials.

Materials and methods
Materials used to conduct the experiment were deflection rig, two weight hangers ,material rods(steel aluminium alloy pure aluminium PMMA, timber ,nylon)varying weights ,ruler , electronic vernier calliper. Method

Before the experiment was conducted ,protective goggles was worn to ensure eyes are protected from fragments of flying materials that are likely to come about as a result of breaking the rods. After inspection of the apparatus the venier callipers was closed and turned to record in millimetres. The steel rod was placed into the nylon collect and tightened .measurement of 200 mm was taken from nylon collet and weight hanger is placed on the steel rod then locked afterwards. Venier is lowered until it comes into contact with the steel rod and the reset to read to read 0.00mm on the display. Weight of 1 kg was placed on the hanger and the venier lowered until it touches the top of rod. The deflection is then recorded, and placed in a table as in fig 1; theoretical deflection of just the steel rod, collet deflection and collet deflection per kilogram and average collet deflection is calculated for the steel rod The rest of the materials are tested in the order of aluminium alloy, pure aluminium, PMMA, timber and then nylon. In all instances force was calculated, measured deflection, collet deflection and material deflection, then put in a form of table as illustrated in fig For the aluminium a weight increment of 1 kg was used and 6 readings acquired. For the pure aluminium a weight increment of 1kg was used only three readings was recorded as a result of the calliper not being able to take readings when more than 3 kg is added. For PMMA a weight increment of 0.2 kg starting off with a weight of 0.2 With the timber rod the weight increment of 0.1 kg was used, material failed after it reaches a weight of 2.2kg For the nylon rod a weight increment of 0.1 kg was used, the calliper could not read anymore than 0.5 kg a force deflection graph was plotted based on the information from the measurements, with the force on y and deflection on the x axes.

Fig 1:
Steel| | | | |
Mass(kg)| Measured deflection s+Cδ(steel rod +collet)(mm)| Theoretical deflection of just steel rod ‘Tsδ(given that w=0.63δ)mm| Collet deflection‘cδ’(mm)| Collet deflection per kilogram(mm/kg)| 1| 2.06| 1.59| 0.47| 0.47|

2| 4.66| 3.17| 1.49| 0.75|
3| 7.14| 4.76| 2.38| 0.79|
4| 9.65| 6.35| 3.30| 0.83|
5| 12.38| 7.94| 4.44| 0.88|
6| 15.90| 9.52| 6.38| 1.06|

Fig 2
Aluminium alloy| | | | |
Mass(kg)| Force(N) (mass x gravity)| Measure deflection M+Cδ (material+ collet )(mm)| Collet deflection‘cδ’(mm)| Material deflection (measured deflection –collet deflection| 1| 9.81| 6.78| 0.80| 5.98|

2| 19.62| 11.97| 1.60| 10.37|
3| 29.43| 18.50| 2.40| 16.10|
4| 39.24| 24.14| 3.20| 20.94|
5| 49.05| 30.49| 4.00| 26.49|
6| 58.86| 36.40| 4.80| 31.60|

Fig 3
Pure aluminium| | | | |
Mass(kg)| Force(N) (mass x gravity)| Measure deflection M+Cδ (material+ collet )(mm)| Collet deflection‘cδ’(mm)| Material deflection (measured deflection –collet deflection| 1| 9.81| 7.83| 0.80| 7.03|

2| 19.62| 46.12| 1.60| 44.52|
3| 29.43| 107.64| 2.40| 105.24|

Fig 4
PMMA| | | | |
Mass(kg)| Force(N) (mass x gravity| Measure deflection M+Cδ (material+ collet )(mm)| Collet deflection‘cδ’(mm)| Material deflection (measured deflection –collet deflection| 0.2| 1.96| 28.77| 0.16| 28.61|

0.4| 3.92| 52.93| 0.32|...
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