1.1.1 Engineering Goals, Identification of Problem and Specific Requirements
To design and make a model motor bridge which displays high structural efficiency i.e. high strength-
- To design and build a bridge that has a structural efficiency of at least 100
- To build a bridge that weighs less than 0.30 kg
- To build a bridge that can hold up to 30kg without experiencing bridge failure
1. What advantages does the glue we were provided with have over other stronger glues?
2. How do we ensure that we will use the least amount of ice-cream sticks to build a bridge that can support the most weight?
3. Where can the Physics concepts we have learnt in class be applied to the building process of the bridge?
4. When does the structural failure occur?/What defines structural failure?
5. Why do the weights have to be placed at the centre of the bridge?
6. Who can benefit from the bridge building project?
7. How can we ensure that the bridge does not undergo structural failure during test?
8. What is the highest score for structural efficiency that can be obtained using a bridge that fits the specific requirements, and how can we build such a bridge?
1. The model bridge may be constructed from standard sized ice-cream sticks only. No other material is allowed. The dimensions of the standard sized ice-cream sticks are estimated as follow:
Length: 113 mm Width: 10 mm Thickness 2 mm
2. The ice-cream sticks may be cut or joined in any fashion. Joining may be done with any commonly available adhesive / glue only. No other material, i.e. string, tape, wire, nails etc, is allowed.
3. The bridge may be stained, painted or coated in any fashion.
4. The bridge must have a length between 550 mm and 650 mm, a maximum width of 120mm, a maximum height of 200 mm and a maximum weight of 500g. There will be penalty for non-compliance (see Table 5).
5. The load will be applied downward using a loading bar placed across the centre of the deck and masses will be supported on a suspended vertical loading rod. (See Figure 1)
6. To simulate a real-life bridge, the model bridge must have a deck for motor vehicles to travel on.
7. The bridge must be constructed to allow for the loading bar to be placed across the centre of the deck.
8. Loading will stop once bridge failure occurs. Bridge failure is defined as the inability of the bridge to carry additional load with any member of the bridge breaking, or total collapse whichever occurs first.
9. The structural efficiency, E, of the bridge will then be calculated.
E = Load supported in grams / Mass of bridge in grams
10. All construction and material requirements will be checked prior to testing by the judges. Bridges that fail to meet these specifications will be disqualified.