Aerospace
Engineering Explorer Post
Sponsored by Lockheed Martin
Updated Tuesday, 3/10/2020
Strong Column Competition 2020
While the March 10th, 2020 was cancelled, the advisors were able to crush a few teams' columns and below is a summary of the results! Thank you to all of the teams who were able to drop off their columns. If your team was unable to submit a column, please feel free to email us a picture of the finished design!
Scoring:
Teams were scored based on their specific strength which is the ratio of supported load to total weight of the tower itself. Because no team successfully predetermined the failing member, the winning team was simply chosen based on specific strength. Despite having a heavy column, the winning team was able to support 1566 lbf, giving them the highest specific strength of 17509! By comparison, an empty metal food can only supported approximately 500 lbf, giving it a specific strength of 5061.
Specific Strength = Weight Supported (lbf) / Column Weight (lbf)
Team 1:
This team selected a simple triangular design adorned with some non-structural purple ribbon for added style. When loading the column, some of the vertical supports began to show signs of buckling and the tower ultimately failed in one of those vertical supports; effectively shearing the support entirely.
Total Supported Load: 42 LB-F
Specific Strength: 1365
Team 2:
Team 2's column looked very similar to Team 1's design, however this team used multiple vertical pieces of balsa wood at each corner support, resulting in a structure that was fairly resistant to buckling. During compression testing, the vertical members were capable of holding a large load despite being very deformed and on the verge of buckling. The failure was very localized to the separation of one vertical support and the rest of the structure remained stable!
Total Supported Load: 182 LB-F
Specific Strength: 3307
Team 3:
This team selected a highly unique design made of up multiple offset triangles; seemingly inspired by Miura-ori based origami structures. The column itself was the lightest column tested yet was still capable of supporting an applied load before the uppermost triangular sections began to detach from the main structure. By using this unique tessellation of triangles, the column was resistant to buckling and simply yielded as a result of the materials and joint design.
Total Supported Load: 15 LB-F
Specific Strength: 735
Team 4:
Team 4 chose a design very similar to our advisor column, utilizing four vertical supports made of multiple beams glued together for a greater cross-sectional area. Like many columns, the horizontal and diagonal cross bracing did not fracture simply due to the fact that the applied load travels directly down the vertical supports. Thus, by using four supports with a large cross section, this team was able to support a very high applied load. Unfortunately, it appears Team 4 used bass wood rather than balsa wood, which is also why their supported load was extremely high. Despite this, the column failure was a nearly perfect example of buckling!
Total Supported Load: 1328 LB-F
Specific Strength: 12,894
(Disqualified for using bass wood)
Team 5:
Once again using a triangular design, Team 5 was the only team to use fishing line to help hold their vertical supports together. The design used 16 vertical beams per corner support which resulted in a very strong column overall. As noted with Team 4, the large cross-section of each vertical beam meant that the supports could handle very high loads and experience significant deflection before the member buckled and the pieces of wood separated!
Total Supported Load: 1566 LB-F
Specific Strength: 17,509
Team Advisor:
Our machine operator also built a column to test with the hopes of setting the record for high support load. The design was analyzed using Finite Element Analysis (FEA) which predicted the column could survive up to 1300 pounds of force! The design used 16 vertical beams per corner support, but the center of each support was hollow to help conserve mass while offering the stability of a large cross section in each vertical support. As with all columns tested, the cross bracing survived in nearly perfect condition, but each vertical support buckled under the applied load until one member finally snapped and the wood separated.
Total Supported Load: 1936 LB-F
Specific Strength: 19,630
