We Helped With This MATLAB Programming Homework: Have A Similar One?

MEC327 Coursework Brief

In this assignment you will work with datasets collected from tap tests of two steam turbine blades. One dataset is provided with this brief, the other will be collected by you in the lab (week 7/8). In the lab, you will follow the same procedure that was used to collect the dataset provided; during the tap test you will collect the responses from an accelerometer to hammer taps at different locations on the blade (shown in Figure 1 below). A transducer will be used to record the force impulses from the hammer hitting the blade. 

Figure 1: Tap locations on steam turbine blade – labelled 1-10 on the steam turbine blade (same locations used for both blades)

There are two elements to this assessment:

(a)    Produce code: you are required to develop a MATLAB script to analyse and compare both datasets with the aim of extracting and presenting useful information about the blades.

(b)    Report: produce a ‘results and analysis/discussion’ section of a lab report focusing on the data you collected in the lab (1000 words max).  

Please see overleaf for more details on each element.

Please note that your code should NOT be developed in collaboration with anyone else, software similar to Turnitin will be used to check your submission and any cases of collusion will be a disciplinary matter. Don’t show your code to other people and don’t discuss how you approached the tasks.

MATLAB component

As a minimum your MATLAB code should produce plots of three frequency response functions from both datasets and identify the lowest five natural frequencies (in Hz) for each blade. Please ensure the computed natural frequencies are stored in a vector labelled nat_freqs_blade1 for the data provided and nat_freqs_blade2 for the blade you have tested in the lab. 

Further marks will be available for identification of the mode shapes for the first three modes (please store these as m_shapes_blade1 for the data provided and m_shapes_blade2 for your blade data) and for comparisons made between the two datasets. You should normalise the mode shapes so that displacement at point 9 on Figure 1 is equal to 1. Any damping ratios used in the calculation of mode shapes should be stored in a variable ‘modal_dr_blade1/2’.

You will also be marked on whether your code runs successfully, on how compact it is, on how easy it is to follow and finally on whether your choices for signal processing were appropriate.

There will be lots of opportunity to gain help and advice on your code, however, the demonstrators will not be allowed to help with all of the aspects of the assignment – some tasks will need to be attempted on your own. Please see below for how marks will be awarded and which elements you can access help for.  

Submission instructions:

Place your code (including any functions you have written) and your tap test data in a zipped folder – your tap test data should be stored in a .MAT format (you can use the function get_tap_test_data provided in the computer lab tutorial to do this). When marking, your folder will be unzipped and set as the current directory in MATLAB. The MAT file blade1_data, provided with this assignment, will be added to your folder during marking. Ensure that your code includes a call to load both datasets.

Report

The report should present and discuss information on the modal properties of the blade that you tested, it is up to you what to present. At a minimum, the report should present a plot (or plots) of three frequency response functions and include discussion of these results (and their implications). If you wish to include some comparison with data from the other blade to help your discussions, you may, however, the main focus should be on what you can say about the results you gained from your test.

You should assume that a full methodology has already been written. There is, therefore, no need to discuss the theory or the test set up or procedure. Discussion of the signal processing decisions you made would only be relevant in the context of discussing possible errors in the results.

There is no page limit for the report but a strict word count is applied. The word limit is 1000 words, figure captions are included in this word count but references are not. Appendices may not be used. A mark scheme for the report can be found below.