Week 10 Assignment: Term Review

            This past week during class, all of the groups got a chance to test their bridges to see who had the lowest cost to strength ratio. Each group came in with their completed bridge and we all used sand to test how much weight our bridge could hold. Our bridge ended up doing worse than we thought, and only held 9.8 pounds. From each group’s results, the cost to strength ratio was determined and the group with the lowest ratio received extra credit. Now our group’s focus is on the Assignment 4 and working together to create a report of all of our experiences for this term.

            In the beginning of the term we were given a goals list that we were told we would meet by the end of the term. From this goal list, aside from the fact that teamwork was probably the largest part of the class, I learned a whole lot about the design process, physical modeling, and forensic analysis. Each task that we were asked to perform in this class secretly helped us work closer and closer to the goals we set. I think that all the goals we set and everything we did in the lab benefited us in some way or another, nothing stood out to me to be the least beneficial. All of the planning, designing, testing, and analyzing we did will one day help us become better engineers. For me, as a mechanical engineer, the best aspect of this class was the designing and testing process. I hope to work with airplanes one day, testing them and assembling them and making sure everything works the way it is supposed to. I think to improve this course maybe instead of just testing our final bridge once; we should test our bridge then have the opportunity to asses the problems and see what we think we can do to improve the bridge. I felt like when our bridge failed, I really didn’t know what to do in order to fix it and make it stronger.

Kelsey McSorley 

Week 10 - Term Review

           This week we had our final competition. This did not go as well as I anticipated. As a group we took a big risk. We used a design that conceptually sounded like a good idea. It was low in cost and on paper seemingly efficient. Well, we made a big mistake. This bridge did not hold the weight I anticipated. It broke under the meager weight of 10 pounds in comparison to my last design which held 20 pounds.  This mistake was due to not keeping the X cross sections on the sides and moving them to the bottom members. We should have stuck with our original design. If we modified it we could have reduced the cost and maintained the amount of weight it held making our cost to weight ratio better.

               

             This class was a lot different than all my other Engineering courses this term. The course was designed to teach the students many topics like computer modeling, teamwork, static analysis and documenting. While every topic was touched upon, I really only felt that I truly learned about half of them. I definitely felt that I learned a lot about documenting, teamwork, computer software, computer modeling and design process. Out of all these topics I felt that I learned the most about documenting. I felt that blogging made me document the process correctly. I felt this was the most beneficial thing I learned. As an engineer I will always need to document and record my processes, designs and results. Overall I loved this class but I would have loved it a lot more if the work was more individual and less structured. I wanted time to test our bridge in lab which would have allowed me to experiment with more designs. I also would have liked if the goals and objective were clearly laid out before class so once I entered class I could use the 2 full hours of class and start working right away.  I believe Engineering 103 should be a class where the student is in control.  Students should have to complete certain tasks by a certain time but I feel that the work should be individual and guided by the Ta’s and professors.

Video of Bridge 2

Week 9: Bridge Process

Last week in lab, my group and I reflected on our work so far and discussedwhat needed to be done. We decided on two major things:

#1: resolve the technical issue involving Bridge Designer

#2: create a final bridge design

We tackled #1 within the first half hour; which left #2, possibly the most important assignment of them all. After contemplation, it was agreed upon to start an entirely new design. Our previous design, while well thought out, did not perform as well as we had expected and had a weak cost/weight ratio. Thus, I began a different design in both technical and aesthetic aspects. The new bridge features a bottom cross-section for reason of adding strength. Our previous design failed front and center and I believe that this new addition will account for previous weaknesses. Secondly, the elevation view includes that of an incomplete cross section, where an additional member runs correspondingly in a primary Howe truss.  Unlike the Howe design, both sides mirror the other. The incomplete cross-section was incorporated for the sole reason of cutting costs while still providing weight displacement along the bridge. Nevertheless, complete cross-sections were added to the bridge ends to prevent compressed failure. Middle horizontal beams were also added for strength purposes.

I hope to find that during this week’s lab our design will prove to be successful. For these last upcoming labs, testing our design is essential to achieving success. Changes will be made based on our test results to determine our final competition design.

Week 9 - Bridge Process

Last week during lab, I was terribly ill and had to go home to the doctors but my teammates filled me in on what I missed. I know one major focus of last lab was to fix the bridge designer. During the week leading up to lab, I did the bridge design modeling of our own bridge for the entire team. The bridge designer program gave me many problems. It would not calculate the loads experienced by the beams in the bridge. After experimenting with it on my own for over an hour, I realized that the program did would not calculate the forces with the x styled center supports. If I took these supports out the bridge would just be a series of squares and in no way replicate the forces in our bridge. I did a few calculations on my own and submitted the image with an error. I know in class that DJ worked with Kelsey and concluded the same thing I did. Kelsey and Chelsea then created a new design with no X supports and modeled that on the bridge designer. This design will be altered again before next lab.

              

          This course reinforced many things I already knew about bridge construction and taught me a few new things as well.  Designing a bridge is not as easy as it seems weather it is out of paper, Knex or steel.  There are so many factors that go into constructing a good, safe and efficient bridge that are easy to overlook.  The easiest thing to overlook is cost. Bridge designers want their bridge to be safe, aesthetically pleasing, functional, practical, safe and memorable (designers want their bridge to stand out from the other, ex: The Golden Gate Bridge).  With all these objectives it is east to get carried away with creative designs.  Before you know it your bridge costs over a million dollars. Learning how to keep cost low, was by far the biggest challenge and learning experience I had in this course. This course was a great learning experience and enhanced many things I already knew about bridges. J