Posted: September 13th, 2017

Data Acquisition and Analysis

Data Acquisition and Analysis

Learning outcomes
The assignment should produce sucient evidence for partial fulllment of the following module learning outcomes:
a. Develop a program utilizing object oriented programming
b. Apply computer based techniques engineering problems
e. Write eective formal written reports.
Additional information
It is recommended that candidates use the LYX template as demonstrated to you in the workshop sessions for the nal
presentation of this assignment. As per the module specication, this second assessment for learning activity accounts for
30% of the module.
Resources: SciLab and MAXIMA all being available on the university networks.
Special requirements: provided on a one-to-one basis for candidates requiring these in specically arranged surg-
eries.
Release date: 19 February 2015
Submission date: 20 April 2015
Figure T1: Typical plotted test data
1 Background
As candidates will be aware from their classes in mechanics, components are designed in order to withstand particular
design loads and/or displacements which are usually decimated by the specic design code as well as the so called ‘failure
mode’ of the material . In order to compare the strengths of various materials it is necessary to carry out some standard
form of test to establish their relative properties.
One such test is the standard tensile test in which a test specimen of uniform cross-section is subjected to a gradually
increasing tensile load until failure occurs. Measurements of the change in length of a selected gauge length of the bar
are recorded throughout the loading operation by means of extensometer. One machine which is used to carry out such
experiments is the INSTRON 3367 which consists of an electromechanical load frame designed to apply a load to a test
specimen via the moving cross-head. The drive system moves the cross-head up to apply a tensile load on the specimen,
or down to apply a compressive load. A load transducer (load cell), mounted in series with the specimen, measures the
applied load. The load cell converts the load into an electrical signal that the control system measures and displays. Strain
transducers (extensometers) can also be used on these systems to measure strain. It is usual to obtain vast amount of
data from these devices which requires some degree of post-processing. It is this post-processing that is subject of this
assignment. From the data resulting from such a test machine candidates will be expected to evaluate properties such as
strength, elastic modulus and stiness.
The assignment therefore has obvious links with the Engineering Analysis modules (MS1060/3) as well as Engineering
Mechanics. Candidates will be expected to research information using a variety of library resources within the introductory
mechanics of materials concepts and principles. The rst task of the assignment has been designed to test the candidates
computational statistical and data-analysis skills developed throughWorkshops. The nal task will demonstrate document
preparation (including referencing) and report writing abilities.
Task 1:
The raw force(kN) and displacement (mm) data from ve test samples of extruded polypropylene (PE) pipe using an
INSTRON 3367 will be emailed to you separately in the form of a single text (:txt) le. Note that these data are unique
to you and will be very similar to that shown in Figure T1 . Clearly justifying any assumptions when post-processing
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these data and complete the following;
a. Identify and separate the ve individual data les within your single text le. Produce smoothed plots with error
bars with 95% and 99% condence limits and comment on the results obtained from the smoothing process {10}
b. Each of the specimens are 75mm diameter with a wall thickness 3mm from the smoothed data produce a stress-strain
curve for the PE. Hence or otherwise evaluate at the 95% condence level:
i. The ultimate tensile strength {2}
ii. The material yield stress {3}
iii. The elastic modulus {5}
iv. Bulk modulus {2}
v. Rigidity modulus {2}
c. Describe an experimental method that could be used to simultaneously record the transverse strain and discuss how
this could be employed to validate the calculations you carried out in the previous question [6].
(30 marks)
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21.94 24.27 26.51
23.02 24.31 22.23
26.84 24.74 23.88
24.79 22.14 24.17
18.12 24.22 24.26
24.66 24.07
25.55 25.55
24.65 24.08
23.30 23.91
23.46 26.41
Table 1: Failure loads of a sample of 25 pipes
Task 2:
The ultimate loads achieved from a sample of 25 pipes is shown in Table .
a. Using an open-source equivalent to MATLAB (e.g. SciLab), add the ve values from the data sets employed in task
1 and convert all the values to stresses in MPa. {5}
b. Produce a frequency diagram (histogram). From your diagram state the modal class. Hence or otherwise make an
estimate of the modal yield of the pipes. {5}
c. Produce a cumulative frequency diagram and make an estimate of the median of the data. {5}
d. Evaluate three further measures of the central tendency of these data and comment on your results. {5}
e. Evaluate two values of the data dispersion explaining your results clearly. {5}
f. A Russian petroleum company requires 95 pipes made of an identical grade PE. Use a z-score [2] or otherwise to
predict the probability of a batch of pipes making the order if the minimal yield stress should at least than 33.8MPa.
{5}
(30 marks)
Task 3:
Write a report (1000-1200 words) entitled. Tensile testing of the polyethylene pipes for energy production.
The report should take the form of a laboratory report using, where appropriate, diagrams to describe the test
performed and state the mechanical/material properties the protocol determines. Write up these nding together with
the results in task 1 in an accepted scientic manner. Ensure that at all times the report is written in the third-party and
the past-tense [4]. For instance, you could consider using the LYX template which we designed in class consisting of the
following sections.
Abstract This is usually written once you have completed the report.
This being included as part of the pre report and be no more than a paragraph detailing: what was done?
What was the key result, and.
What was the main conclusion?
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1 Introduction
This should say a little about the use of the physics of materials and the use of any mathematical formulae. This
section is usually used in order to set the scene of what the assignment is about. In addition, should also clearly state any
assumptions evident in the work that and validate these using appropriate cited references.
2 Method
Here you should include the rest of the relevant information pertaining to the details of the tensile testing procedure as
outlined in the opening paragraph of this task. Rationally, describe the methods you have employed (stating any formulae
used in the completion of Task 1). Ensuring at all times that appropriate citations are used throughout via application of
a standardized referencing system.
3 Results
Present all your tabulated and graphical results in order to answer Task 1: parts (a) to (c) and briey comment on
observation that can be inferred. Ensure that all graphs produced in task one are included, correctly formatted and
captioned Figures so that a List of Figures and Table of Contents are generated automatically.
4 Discussion
Include all your data comparisons for parts (d) to (f) of Task 1 and most importantly comment on each results.
5 Conclusions
What did you nd out and what did you learn?
Do you have any recommendations?
References Ensure that all references are cited throughout the main text and the Harvard (ISO 690a) or Vancouver
system (ISO 690) is employed at all times.
(40 marks)
Submission details:
The assessment is very much an assessment for learning to this end similar work to that expected here will be covered
extensively in workshop sessions, two of which will be specically arranged for you work solely on the assessment. Referring
to the appropriate module descriptor the report and presentation should typically describe progress commensurate in the
aforementioned workshops with about 20-30 extra hours work conducted outside these sessions.
The deadline for submission of the written report is 16:00 on Monday 13th April 2015. Reports should be submitted to
the appropriate assignment submission tray in room CM007 in the C&T Building accompanied by a completed Assignment
Submission Form. As per the university academic academic regulations [5] the usual late submission / plagiarism / poor
presentation penalties apply.
References
[1] Hern E. J., Strength of materials 1, Butterworth-Heinemann, Linacre 1997.
[2] Mendenhall W. and Sincich T., Statistics for Engineering and the Sciences, 2006.
[3] Stroud K. E, and Booth D., Engineering Mathematics, Pelgrave McMillan, 2001
[4] Silyn-Roberts H., Writing for Science and Engineering. London : ButterHeinem ST, 2000.
[5] , Anon. Academic regulations (hollowed be them), University of Central Lancashire, 2014.
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