Procedure: First my Partner and I created the five trusses, truss 1 (2 of them), truss 2 (2 of them), and one custom truss. We made all of the trusses with glued together balsa wood sticks. We found the mass of every truss and placed them onto a contraption to measure the force it takes for them to break the trusses.
Our Truss 1 sketch
|
Our Truss 2 sketch
|
1) Custom truss
2) Truss 1
3) Truss 2
2) Truss 1
3) Truss 2
|
|
|
Efficiency Evaluation
Truss 1
Statically Determinate? Yes (2x3=3+3)
Reaction Forces? 11.27N (load), 5.6N (RCY), 0N (RBX) Tension Or Compression? 20.33 compression (AB), 20.33 compression (AC), 46.49 tension (BC) |
Truss 2
Statically Determinate? Yes (2x5=7+3)
Reaction Forces? 26.97N (load), 0N (REX), 13.49N (RCY), 13.49N (REY) Tension Or Compression? 26.2 tension (AD), 13.49 tension (AC), 26.97 compression (BD), 52.37 compression (BE), 67.34 tension (CE) |
Custom Truss
Basic Constraints? 36in balsa wood, triangular shapes, statically determinate, the glue, and the time.
Statically Determinate? Yes (2x8=13+3) Reaction Forces? 50 N (load), 25 N (REY), 25 N (RAY), 0 N (RAX) Tension or Compression? 57.7 compression (AC), 57.7 tension (AE), 57.7 compression (CE), 14.71 tension (BH), 14.71 tension (DF), 51.96 compression (CH), 51.96 compression (CF), 50 compression (CG) |
1=Best
2=Good
3=Not so Good
2=Good
3=Not so Good
Final Design Choice (Pink)
Explain why you think failure occurred at the truss member where it did. Did your truss fail at the member your calculations revealed as undergoing the most stress? The failure occurred in the truss member where there was the most stress according to our calculations. The reason mostly being the distribution of force, there wasn't enough force being distributed evenly throughout the truss which caused it to break where it did.
If given a chance to redesign your truss after testing, what changes would you make? I would keep the outer shape of the truss but change the inside members to where 1 was going directly horizontal, one going directly vertical, and other members going diagonal, to help the truss really distribute the force throughout the entirety of the truss instead of on the one member which broke on our original design.
If given a chance to redesign your truss after testing, what changes would you make? I would keep the outer shape of the truss but change the inside members to where 1 was going directly horizontal, one going directly vertical, and other members going diagonal, to help the truss really distribute the force throughout the entirety of the truss instead of on the one member which broke on our original design.