INT0067 Physics, Engineering and Applied Mathematics
Laboratory Exercise - Tensile Testing
The purpose of this laboratory exercise is to familiarise you with the typical tensile test method and its application to metals and polymers.
The materials tested in this experiment are steel, copper, acrylic (PMMA), and polypropylene. Each specimen used in the test is shaped as shown in Figure 1. The dimensions of each specimen will be carefully measured before testing so that the tensile stress (σ) and strain (ε) could be determined from the data recorded during the test.
Figure 1 Test specimen with dimensions l, w, and t.
For the test itself, each specimen will be secured into the INSTRON machine and loaded until failure.
While experimenting, you should take notes and record your observations. What happens to the test-piece during the test? What changes in shape can be observed? What is the nature of the final failure (how does the piece break)?
You can then use the data provided to produce a graph of tensile stress vs. strain for each material. From this graph, you can measure quantities such as the yield stress and ultimate tensile strength of the specimens supplied (and perhaps Young’s modulus, where possible). The data also contains final measurements for each specimen (where possible), which you can use to calculate the % elongation and % reduction in area of each material.
Think about what each of the above quantities tell you about the material properties of each specimen (remember your materials vocabulary!) and use your graphs and data to make comparisons and draw conclusions in your lab report. Think also about applications for the materials you have tested, based on your conclusions. For example, if you were to fashion a door handle out of one of the materials tested, which would be the most appropriate and why?
You must submit your own formal lab report including a brief description of the experimental procedure, your measurements and the graphical results, and an analysis/interpretation of the results. Detailed guidance on writing the report is given below.
You must also complete the laboratory worksheet during the lab session to evidence your work, and include an Excel spreadsheet with all analysis. Your report will consist of:
Laboratory Worksheet (scan or photograph and include as separate file or as an image in your report)
Written Report (.pdf, .doc, .docx, etc.)
Spreadsheet with all calculations (.xlsx or other format)
Late submissions will be subject to penalty.
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INTENDED LEARNING OUTCOMES (ILOs) (see assessment section below for how ILOs will be assessed)
On successful completion of this module you should be able to:
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Module Specific Skills and Knowledge:
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2
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apply basic concepts in the analysis of mechanical, electrical and thermal problems
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5
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recognise when particular techniques are used in a variety of mathematical or engineering situations
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Discipline Specific Skills and Knowledge:
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6
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interpret results of laboratory experiments
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7
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demonstrate understanding of theoretical principles through application to problems
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8
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interpret answers to problems with appropriate accuracy
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Personal and Key Transferable/ Employment Skills and Knowledge:
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9
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apply appropriate methods to address a well-defined engineering problem
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10
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communicate effectively in the written form
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Writing your Lab Report
Please use the guidance below to help you write your Tensile Testing lab report. The report should be word-processed using Arial Font, size 12, with 1.5 line spacing and standard margins and you should include your student numbers in the header of each page. You should write your report in the past tense and avoid the use of “we” or “I”.
Important Notice Regarding AI Use
This piece of work can be “AI-supported”. This means you may use generative AI e.g. ChatGPT ethically and responsibly e.g. to produce a suggested outline or to summarise a source. However, you must not copy directly from an AI-generated source (or any other source, including the work of other students) when writing your report – it must be written in your own words. Copying from an AI-generated source is treated the same as plagiarising any other source, and this is considered academic misconduct. This includes copying text, images, videos or any other material generated by the AI.
If you use AI, you must reference it in your report, and also keep a record of all prompts and output from the AI (e.g. copying text or taking screenshots). Your teachers can ask to see this information after you submit your work if they suspect AI misuse.
Please see the University of Exeter guidelines on AI use here: https://libguides.exeter.ac.uk/referencing/generativeai; this includes guidelines on how to reference AI use.
In addition, whether you have used AI or not, you must add the declaration on the next page at the start of your report. Please copy and paste it into your document, ticking the appropriate boxes.