[SOLVED] MECH0053 Power Transmission and Auxiliary Machinery systems 2024/25

Coursework Assessment Brief Coversheet

Use of Generative AI

This assignment is classified as Category 2: AI tools can be used in an assistive role. More implications of this can be found in the assessment brief.

Assessment Criteria

Learning outcomes assessed:

L1 design and select components in a power train.

L2 design shafts for static and fatigue loading and select an appropriate type of coupling. L3 design friction clutches and distinguish friction materials and mating surfaces.

Please turn over for specific guidance:

Specific guidance:

There is an upper limit of 6 pages (excluding a title page) and a maximum 5000-word limit for this report, which must be typed. Pages should be numbered, and the font should be no smaller than 11 pts to make the document easier to read and mark. If you do use external material, then this should be referenced in accordance with UCL procedures. If you are using any table or graphs that are provided in the lectures or are from the reference list of the lectures, you just need to cite the table number and identify the reference that you are using, e.g. Table 5.4 of Childs. Do not use the space to replicate those tables or graphs.

It is essential to read and answer the questions and to ensure that all aspects are addressed. Working methods need to be clearly presented so that markers can credit your work even if the answers are not fully correct. Ensure that your work is presented in a professional way and that any figures used are labelled correctly. Use a maximum of 6 pages in the most efficient way to ensure that you present all the information that you need to answer the questions. This will give you the greatest opportunity to gain higher marks.

Tips for success:

Q1:

a) Provide a clear schematic of your design. You may scan a schematic drawn by hand but it should be of a professional standard (e.g. use a ruler). You may use CAD software for the drawing but it is not a    requirement. You should show clearly the dimensions and any provision you use to locate the components, reduce stress concentration, etc.

b) Demonstrate your calculation clearly. If you are choosing any parameter you need to justify it but be concise and clear.

Q2:

a) You need to clearly state your reason for choosing a specific type of coupling based on the problem and the information provided. State any assumptions that you make.

b) Similar to Q1 (a) demonstrate your calculations clearly and justify any parameter that you need to choose.

Use of AI:

Category 2:”AI tools can be used in an assistive role” . Students are permitted to use AI tools to assist with giving feedback on content, or proofreading content and the creation and formatting of figures, but the design and technical content is the student’s responsibility and must be their individual contribution.

If you have used AI in anyway, you need to declare it in the report or presentation in the following way:

• Name and version of the generative AI system used, e.g. ChatGPT-3.5

• Publisher (company that made the AI system); e.g. OpenAI

•     Brief description (single sentence) of context in which the tool was used.

More details are given here:

https://library-guides.ucl.ac.uk/referencing-plagiarism/acknowledging-genAI

Assessment Brief

1. You are tasked with the design of a high-speed driveshaft which is used to transfer power in a pharmaceutical application. The machine works at varying temperatures but it would not exceed 100 °C. The schematic of the locations of the components is shown in Figure 1. The power to be transmitted is 19 kW at 11000 rpm. The shaft is driven by spur gearA and the power is transferred through coupling B to a separate shaft (not shown in Figure 1). Assume no bending moment or shear force is transferred via the coupling and its mass can be ignored.

The shaft is supported with two ball bearings. Assume the gear hub has a width of 30 mm with a fillet radius of 1.5 mm. The gear is 20° pressure angle spur type with a pitch circle diameter of 90 mm and a mass of 3 kg. The shaft is to be manufactured using alloy steel with σut  = 1200  MPa, σy   = 900  MPa, E  = 205  GPa, G  = 80  GPa and Brinell hardness approximately 300 BHN.

a)  Provide a schematic drawing for your designed shaft. You need to justify your choices for your design, for example how you would locate components, etc.   [5 marks]

b)  Obtain the size of your shaft for unlimited life and faultless operation. Your shaft should be sized for a reliability of 99.9%. Consider an appropriate factor of safety and any other parameter that you need to define. You must justify your choice of parameters.  [10 marks]

Figure 1. The schematic view of the assembly of question 1.

2.

a)  Select  an  appropriate  coupling  to  connect  the  two  shafts  of  question  1.  State  your assumptions and justify your choice of the coupling.       [4 marks]

b)  The  coupling  of  the  shaft  in  question  1  is  connected  to  a  clutch  that would  operate frequently and would partially cool down between applications. It accelerates a mass of 12 kg with a radius of gyration of 0.2 m from rest. The system is driven by an electric motor. The friction surfaces would be made of woven materials. Design a disk clutch and obtain its parameters. Show clearly how you obtained the parameters, justifying your choices, where appropriate. What would be the slip time of your clutch?    [6 marks]