One of the most fundamental decisions guiding the construction of the car is the choice of materials. The strength and weight of materials used decides the size and type of stock used to create components, as well as dictates in part what manufacturing techniques we can use. This dependency also works in inverse, for example it would be foolish to choose aluminum for important large scale structural features of the car because at the moment we are unable to weld aluminum or heat treat welded parts.
Another and more important constraint we have are the guidelines surround the construction of our car as outlined in the 2019 Solar Car Challenge Event Rules and regulations document. For some parts of the car, specific alloys and material gauges must be used in order to comply with the competition. In many of these cases the choice is between carbon steel and aluminum. In these cases we have opted for steel due to limited manufacturing capacity. Currently our choices of methods to join metal are limited to a MIG welder and screws, which means that the bulk of our design will be steel.
Recently, the design of the suspension for our car has been one of our top priorities. For this part a high degree of ease of manufacture is preferred due to our tight schedule and the desire for high speed of design iteration. These parts also need to be very strong because they will be sustaining a large amount of irregular force from the movement of the car. Since the strength of aluminum is lower than that of steel, and strength to weight ratio of aluminum is higher than that of steel we are machining these parts from aluminum in order to save weight and make manufacturing easier.