Engineering Design III – E 231 – Section D – Group 7|| 11/9/2010|
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The planar truss was constructed according to the requirements of the E231 by attempting to support a large load. Three designs were constructed to fit the necessary requirements. The design with the largest strength to weight ratio was chosen. The truss was then constructed using square brass tubing and then tested for the strength by applying a vertical load with a buster. The goal of the project is to make a truss to hold the most load out of the whole class.
Table of Contents
Overview of design process2
Truss Design Details with Alternative Designs3
Design Analysis Summary6
Calcuations of weakest member and strength to weight ratio6
Assembly techniques and soldering considerations7
Finishing and final weight of the truss in pounds8
Type of failure and rational for the test results8
Ranking within your section8
Ratio of Load failure (lb.) to truss weight (lb.)8
Test results compared to predicted load failure and predicted failure member(s)8 Conclusions and Recommendations:8
Planar Truss Gantt Chart9
Work Breakdown Structure10
Final Design Calculations12
Truss Before Testing13
Truss after testing14
Brass Compression data15
The single planar truss was constructed according to the requirements of the E231 class. The truss was constructed in goal of having maximum strength to weight ratio when a vertical load was applied to the center of the truss. The groups were split up into 3 or 4 people each where each group competes against one another to get the largest strength to weight ratio. This means that the truss would hold a heavy load and have a small weight which would give it a large ratio. The first step in the project was the design of the truss. Three sample trusses were designed on ELICA and then the best design was chosen. The truss was designed using the equation of two joints minus three equals the number of members required for the truss. This equation gave the group the correct number of members to joints. There was limited number of supplies that were allowed for the truss construction. The group was given eighty four inches of total brass and an additional 12 inches to create the gussets. The size of the truss also had restrictions, the bottom of the truss was required to be fifteen inches long and the height of the truss was required to be no higher than four inches. There were also several different supplies given to the group to help facilitate the construction of the truss including: a propane torch, solder and flux. After construction of the truss, testing occurred to see if there were any major problems to be fixed before final test day. In order to properly organize the tasks in building the truss a Gantt chart as well as a work breakdown structure was constructed during the weeks of design. This gave the group deadlines as well as kept them on tasks during the several weeks of construction. Also, by delegating tasks early the group became more efficient working, which ultimately gave them a better final product.
The design, construction and fabrication of truss is described in detail below. There were different design factors for the truss that were taken into account after going through each of the different design experiments. With this knowledge the group designed, fabricated and tested the truss to get the final product. Design
Overview of design process
The design of the truss took many things into consideration. There were several experiments conducted leading up to the design of the truss. There was an experiment the group did...