1.3 - Evaluation Matrix and Design Matrices
















Decision Making Matrix


Criteria Weight SizeAppearance Time to produceCost to produce Ease of use Availability of materials Environmental Impact Safety Row Total Normalised Value
Weight 33330200140.130
Size 0312200080.074
Appearance 0001300040.037
Time to produce 02331020110.102
Cost to produce01203130100.093
Ease of use 31020330120.111
Availability of materials 13332020140.130
Environmental Impact 33310010110.102
Safety 33333333240.222
Column Total1081.000
Criteria
Normalised
Design Idea #1
Design Idea #2
Design Idea #3
Priority
Value
weight0.13020.25930.38930.389
size0.07420.14830.22230.222
appearance0.03730.11140.14830.111
time to produce0.10230.30630.30640.407
cost to produce0.09320.18530.27830.278
ease of use0.11110.11120.22240.444
availability of materials0.13030.38930.38930.389
environmental impact0.10220.20420.20450.509
safety0.22210.22230.66740.889
Total1.9352.8243.639
Comparison Of Designs^^


Choice of materials:
  • We will be using wood as our base/body as wood is sturdy and strong hence, it will be able to take the force of the spring's energy and the rope's tension. Wood in any circumstance will also not bend or snap easily as it is not flimsy, like corrugated cardboard, therefore it is the best to use for the body and a base.
  • We will be using wooden rods as axels because we do not want the axels to be flimsy as they will be rotating the wheels and if they are flimsy, the whole structure can be unstable. 
  • CDs' will be used as wheels because they are light weight, hence the structure would be light and they will also not be a limitation for the axels used as the diameter of the wheel is pretty big. (We will tape duct tape/ balloons to reduce friction) 
1. First idea
  • The first idea was really very unstable as the axels and wheels were not attached properly and the mousetrap was positioned at the back hence, the car did not move.


2. Second Idea
  • The base was too flimsy as it was made out of cardboard, hence after a few tries, the whole base came off the mousetrap. The front wheels did not move as well as it was made out of plastic. The 2 different pair of wheels also made the whole structure unstable.


3. Third and Final Design
  • This design was the most sturdy as it was made out of wood. Also the axels and the wheels were sturdy as wooden rods were used and similar types of wheels (CDs) were used. The minor problem in this were the "joints" (corks) which kept coming out. How we could have overcome this problem was by drilling a hole in the wooden base and fitting the screw eyes in that so that axels would rotate easily. What we have learnt from this is that we should not have too many joints in a vehicle.

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