WEEK 4

13/5/21

For our fourth lesson, it was asynchronously. We were required to look through the materials available on Blackboard and conduct self-directed learning. Based on the resources provided, we learnt the evolution of materials over the years as well as the different classifications of materials. We also revisited material for design (MFD) and the usage of the COWS matrix. As this was already taught in Year 1, this lesson was thus made asynchronous. However to recap, in MFD we learnt about the classification of materials, material properties and testing, and selection of material. We learnt to classify materials into 3 large groups, metal, ceramic and polymer. We also learnt about the different types of properties and tests to carry out in order to determine which material has certain properties. Some of them include, tensile strength, a measure of how long a material can resist tearing due to tension, modulus of elasticity, a measure of how long a material can withstand deformity elastically when stress is applied, and etc. Lastly, we learnt how to select the most appropriate material by using the COWS matrix. COWS matrix is a way of scoring materials based on their most feasible properties for a certain product, and the material with the highest score is deemed to be the most appropriate material to use. How the scores are given are, firstly, we need to list out the necessary criteria that the product needs, such as density, thermal conductivity, yield strength, and so on. Secondly, we are to rank these criteria and give them weightages which should equal to a total of 100%. Thirdly, we compare and contrast the properties of each material corresponding to the criteria, and rank them accordingly from 1 to 3, with 1 being the worst and 3 being the best. Lastly, we calculate the score and discern which has the highest score which will then be used as the material for that certain product. 

To refresh your learning on MFD and COWS matrix, we were given an assignment to use COWS matrix to ascertain the most appropriate material to use for a product assigned to us. For our group, we were assigned with a face shield to protect medical workers against COVID-19, and we were specifically told to focus on the transparent sheet of the face shield and the the support on the forehead. This is what we came up with: COWS matrix

This was all for this week's lesson, it was nothing new, but it sure did freshen our minds on MFD which will very crucial for the making of our chemical product.