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Izzy & Danny's Bridge 

Bridge Design Description

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Brainstorming 

As beginners, this was the first project that we had in our statics engineering class. At first, we did not have a clear direction for how to begin the design process. As a result, we experienced a few challenges given that this was our first hands on experience with the software, materials, and applying our knowledge thus far to a real-world scenario. We began by individually drawing out designs on paper. It took us coming up with a handful of designs to get to the final two, one from each of us. The most important factor we prioritized was having a strong foundation for our bridge.

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Final Design

Ultimately, we decided to design a bridge consisting of right triangles and various members, in order to ensure that our bridge had a strong support system. Given that triangles are the most structurally sound shape, we determined that including them throughout our design would help to equalize the loads on all sides.  We also considered that designing it in that manner would be more simple, whilst maintaining effectiveness. 

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Design Specification Table
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SERVICES

Analysis & Construction of bridge

In terms of analysis, there are various aspects to consider. First, is the use of a method. The method we used to assess our bridge is the method of sections. This method allows us take a section of the bridge and cut it, so that we can then analyze it using the skills that we have learned throughout the course. We began this process by cutting through the bridge and following this, we went on to take a moment at any point of the section we cut. After that, we found an unknown and then summed up the forces in both the x and y-axis. Next, we used the  Truss Simulator software to construct the design of the bridge as well as calculate the hypothetical loads in the bridge and see how it would perform when various loads were applied to it. Unfortunately, our hand writing calculations do not verify what the Truss simulator gave us. There must have been an error in the beginning of our analysis that we did wrong.

Body Diagram
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ABOUT
PROJECTS

Testing Results & Failure Analysis

Before we tested our bridge, we were both a bit nervous. We did not know what to expect. Our goal was for our bridge to easily pass and exceed the minimum load of 66 N. It was important to us that our bridge be able to withstand this load  because doing so would mean that our safety factor would be greater than 1.5, which is a baseline for what is acceptable in terms of safety. As we continued loading more force onto our bridge, we noticed it was holding up well. Once we noticed this, our nerves dissipated as everything appeared to be going smooth. Our course instructor provided a machine that created a graph with data, telling us the load, time, and final load amount before the bridge would break or have something else go wrong. As this went on, our bridge continued to perform better than we initially expected. It felt very satisfying to see a bridge we designed perform successfully and resist a max load of 122.69 N. We were very happy with our max load given that we were originally skeptical that our bridge would perform that well.
 
Although our bridge exceeded the minimum load requirements and our performance expectations, there were a few errors that may have hindered its ability to perform to its fullest. First, not all members were aligned with the bridge. Second, the bridge was not completely straight all the way through. Third, we did not allow the glue enough time to cure properly. Ultimately, difficulties with time management and aligning our schedules were a factor that kept us from adequately addressing these issues; nevertheless, we were highly pleased with our end result.
Instron Test Data
Body Diagram
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