Writing an abstract is one of the hardest skills to master in formal lab report writing. An abstract is normally placed at the beginning of a formal lab report, so that the reader can quickly see what is in the document (including what, how and why the experiments were undertaken, and what were the key findings and conclusions, all in a very limited number of words). The abstract/summary is often the last part to be written. For more information refer to the Technical Writing Guidelines document in the Information and Resources section of the Year 1 Labs and Tutorials VITAL module.
Write an abstract for the Tensile Test lab. The proforma box should limit you to 1400 characters (around 280 words) as the purpose of an abstract is to be concise.
The technical note demonstrates the mechanical properties of metal, specifically mild steel, aluminium alloy, and brass. It shows those properties by using the internationally known testing technique, which is Tensile Testing. The three types of metal were tested with a special mechanism device called the Hounsfield, which contains a special type of electrical transducer called LVDT (Linear Variable Differential Transducer). The proportional limit, young’s modulus, and tensile strength, 0.1% proof stress thus calculating the elongation. In order to calculate the stress and strain the measurements had to be taken for all of the materials such as guage length and cross-sectional areas to observe the extension of the metal. Furthermore, the extension of the guage length was measured in mm with a regular ruler as for the cross-sectional area a micrometre was used. Subsequently, after examining the materials percentage of the elongation from the graph was compared to the one from the metals, which was measured, by comparing the guage length change from before and after the testing of the materials. Also, safety provisions were taken during the experiment for example by wearing the safety goggles and the lab coat. Moreover, keeping a safe distance from the Hounsfield device was keen during the procedure of the testing as the breakage of metals could lead to injuries.
2.1 Sample Calculations
Explain (in less than 20 words) how you obtained the following three quantities in Table 5 (lab script) from the data recorded in this experiment.
Calculation 1: Young’s modulus (Elastic modulus)
|Gradient of the elastic ration of the graph, which is the stress, and strain. Moreover, exploiting the smallest square fit technique, or the alteration in stress that is alienated because of the change in strain for the relative elastic area.
Calculation 2: Yield stress
Monitor the point where the elastic stage ends on the figure and at that point the stress is not proportional anymore with the strain.
Calculation 3: Ultimate tensile stress
It the maximum documented tensile stress for the material.
2.2 Tables and Figures
Table 1: Initial Test Sample Measurements
|Mild Steel||Aluminium alloy||Brass|
|Original Gauge Length of test sample (mm)||91.95||99.11||92.94|
|Original Cross-section Area (mm²)||18.2||24.46||21.15|
|Did the sample fail during testing?||Yes||Yes||Yes|
Table 2: Enter name of the sample material here
Only enter data for ONE of the two samples (i.e. either steel or aluminium) that your group tested in this table:
|Load, F (kgf) from PC display||Load (N) with zero off-set removed||Extension, δ (mm) from PC display||
Extension , δ (mm) with zero off-set removed (if required)
|Engineering Stress, σ (MPa)||Engineering Strain, ε (%)|
Table 3: Mechanical Properties Measured from Stress-Strain Plots (and the Direct Measurements of % Elongation)
Only enter data where appropriate
|Modulus of Elasticity (GPa)||Yield stress (MPa)||0.1% Proof Stress (MPa)||Ultimate Tensile Strength (MPa)||% Elongation at end of test||% Elongation from measuring final length of a 50mm gauge length directly from test specimen|
|Mild Steel||224.78 GPa||234||60||291.8||31.65 %||40.76 %|
|Aluminium alloy||319.74 MPa||88.3||26||100.9||4.46 %||18.26 %|
|Brass||100.27 MPa||336.07||108||444.7||39.10 %||40.02 %|