Task: To observe simple tensile tests on steel reinforcing bars and compare/interrograte their mechanical & physical properties through the use of Load/Extension/Position graphs.
Health & safety:
The Denison Universal Machine will be operated by an experienced technician.
- Beware not to drop steel bars on toes.
- Stand a suitable distance away from the equipment during testing.
- be careful of sharp serrated edges of fractured samples.
Material Samples
- One mild steel plain bar
- One high tensile ribbed bar
Plain Bar:
1. Measure the diameter with the micrometer provided. Take 2 measurements of diameter (at 90° to each other), at four points along the length of the bar. Why??
2. Calculate the average cross-sectional area (CSA) of the bar and inform the technician of the value for input into the Testing Program.
3. Measure the overall length of the bar and weigh it. Calculate the average cross-sectional area based on the density for steel being 7850 kg/m3. Compare the results with 2 above.
Ribbed Bar:
Measure the overall length of the ribbed bar & record its weight. Again assuming the density of steel to be 7850 kg/m3, calculate the CSA of the bar.
Tensile Tests:
Secure the samples (in turn), into the jaws of the Denison Universal Testing Machine and load each bar (in tension), to fracture. Two graphs will be provided from the tensile testing software:
- Load v Position Graph (used for labeling & annotation purposes).
- Load v Extension Graph (used for calculation purposes).
Laboratory report:
Write a laboratory report on the Materials Laboratory. The report should follow the structure outlined below:
1. Front cover: Report title, name and number of candidate, submitted to Dr. M. Boulhibene
2. Aim: Clear sentence on the pussose of the research
3. Introduction. Background Information... manufacture, materiai aerties/behaviour unique to steel, any predictions on sssngth/Elastic modulus? Remember that you need to REFERENCE PUBLISHED TEXTS to back up what you are saying.
4. Apparatus.. List of the apparatus used. Also, a labelled sketch for photo) showing the experimental set up. Is there a standardised apparatus list we should use?
5. Procedure. Description of the experimental method used (should include references to apparatus). Written o tense (eg. The sample dimensions were msssiged...) is there a standardised method we should follow?
6. Results. Put results spreadsheets ill the appendss But, extract key results from these spreadsheets and put in this action. Also put sample dimensions in this section as well.
7. Analysis. Use the spreadsheets to create load-deflection (P-δ) plots. Convert each P-δ plot into a stress-strain (σ-ε) plot.
8. Discussion. The most important part. what can be concluded from the analysis results. Is this result we would expect? (find a reference with which we can compare the results). How does the 01,0 tested compare with onwr types of steed With other mateosis?
9. Conclusion. summarise what you have round out Be clear.
10. References: Any egemal sources of information ressired to In your report should included here.
11. Appendix. The P. δ spreadshssts shout) be included in this section.