Reference no: EM132619719

Introduction

The second year design project for 2020 relates to the colonisation of Mars. Within the context of that project there is an opportunity to apply what you will be learning in Applied Mechanics B to model the behaviour of a suitable mechanism.

In design projects there are often a number of ways that a problem should he viewed so that you under¬stand and appreciate the relationships between function, material selection, energy requirements, types of loads and the nature of the resulting stresses, etc. One such aspect is function, which deals with the particular aspects such as the modes of operation of a device in order to achieve its intended purpose. Once this is achieved then the nature of material selection, forces, stresses etc. can be developed.

The aim is for you to gain some insights into how mechanisms may be used to our advantage, use mathematical techniques to analyse a typical linkage arrangement to assess the motion and function of the mechanism, assess some of the advantages and disadvantages of the chosen mechanism, and have some fun in making a video presentation, which can include an animation of your mechanism.

Topic
In the context of the second year Mars design project, you will be required to select one of following mechanisms as the focus of your group assignment, and utilise a suitable four-bar linkage to obtain the required motion.

1. A Mars habitat door (opening and closing with high positional accurately so as to produce an air¬tight seal). When open, the surface of the door that would normally face the interior of the habitat should not be exposed to the Mars wind and dust. This dust could be harmful to the occupants of the habitat if they were exposed to it. It should have cylinder or cable winch actuation, and should be able to be manually overridden in the event of a power failure.

You are required to spend 15 - 20 hours (maximum) per student to complete the analysis and produce the output, which will take the form of a Google Slides presentation and an animation.

The project should be seen as something different which may become an area that you develop an interest in. It should be fun, and should not require a lot of time to complete. Do not spend excessive amounts of time on it, but, at the same time, each student in the group should contribute to the outcome and should have some fun doing so!

Submission

A presentation and an animation will be submitted by each group. The submission should include:
• Title page. A concise descriptive title indicating the type of mechanism and the Mars application, the group number, the names and student numbers of the group members. An image of your mechanism. Max 1 slide.
• Declaration sheet. This takes the form of the standard declaration sheet used by the School, must include the names, student numbers, signatures and % contribution of each student. Max 1 slide.
• Literature review of 4 bar mechanisms (in general) and a brief introduction to the chosen mecha-
nism in the context of the Mars application. Max 2 slides.
• Advantages and disadvantages of the chosen application in the Mars context. Max 1 slide.
• Graphical layout of the chosen mechanism in the Mars application, showing all geometric param-eters (lengths, angles etc.), as well as the two end positions of the coupler point (and whatever is attached to the coupler point, whether a door, platform, grip or skid). This may be hand-drawn (neatly) and scanned in. Max 1 slide.
• Mathematical analysis of the mechanism: equations of position and velocity of the coupler point which is selected on the basis of the particular engineering application, and which relate the geometry to the independent variable and time derivative thereof. You may use equations from other sources but you must reference them. Do not merely copy and paste the analysis. This may be hand-written (neatly) and scanned in. Max 2 slides.
• Graphs of position and velocity of the coupler point of your mechanism as a function of the input crank angular position and angular velocity (or linear actuating cylinder position, as appropriate). Graphs should also show any any specific points in the motion that give maximum or minimum forces, velocities etc. or where problems may occur which are to be avoided. Max 2 slides. Do not use graphs from references, plot graphs of your mathematical analysis! Do not include acceleration. Max 2 slides.
• Conclusions and Recommendations. Review your design and state whether it can achieve the motion, what your findings were, what its strengths and weaknesses were, and what recommendations you would have for future work. Max 1 slide.
• References. You must annotate your references in your literature review and mathematical anal-ysis. Use a number scheme, .e.g. [1] and then in your references, state the full citation details against the same number. This applies to websites as well. Max 1 slide.
• An animation needs to be submitted. This can be done in CAD or other suitable software and saved as a video, or can be done by making paper or cardboard components of the mechanism in their correct scale, pinning them together, and then taking a series of photographs where the components are moved in small increments. Be creative as there are marks for creativity. Make sure that your group number appears in the video.

Note the following in relation to the presentation:
• Use Google Slides to collaborate so that it is not necessary for all students to have the same
software (such as PowerPoint).
• Use the standard landscape layout.
• You may add themes, borders, backgrounds etc. to make the presentation appealing.
• Adhere to the maximum number of slides per category as stated above.
• Make sure that your font size is such that the presentation is visible on a laptop at least one metre away. Do not use long sentences but short, sharp points that get the message across, with the necessary reasoning.