Ingenieria

Introduction
A truss is a series of individual linear members built together as a unit. These individual members act either in tension or compression. Those that act in tension pull outward at its ends and those in compression push together. Usually, the individual members or “beams” create triangular patterns because a triangle is not easily distorted by stress. In order to design a good truss,the stress has to be evenly distributed among the beams for the truss to be able to support its own weight. The truss is designed to support itself when significant amount of weight is applied by each of the individual beams straining against each other, causing them to hold. The members can be horizontal, vertical or diagonal, and are all connected by bolts. We can see an example of a truss inbridges. The purpose of truss bridges is to make the construction of bridges over places with unstable ground. This can be done because trusses do not have a lot of infrastructure at the bottom, just at the top of it. The truss bridge is still popular nowadays because it can be placed nearly anywhere despite the condition of the ground, and still support a sufficient load.
The purpose of thisproject was to build a 2D truss that could support a minimum of 400 lbs and a maximum of 2000 lbs. We were told the materials we had to use and the constraints we had to work with while building the truss. Our list of materials that made up the truss included: wooden beams (1x4s and 1x2s), bolts of varying lengths and wood spacers. We also used a drill press, handheld drill, miter saw, sander, andseveral wrenches in order to form the materials into a truss. At the end, our group was going to compete with other groups for the lightest and least expensive truss, for the greatest strength to weight ratio and for having the most accurate weight prediction.
To begin our truss design, we first brainstormed different designs. Each of the members of our group came up with at least two possibledesigns until we came up with one we all felt confident was going to work. After drawing our truss by hand, we used a computer program called “Framework” and “Excel” to analyze our design using the stress analysis provided in the program (appendix). With this program we were able to figure out which beams were going to buckle with a giving weight.
To make our truss better we had to re-design it.At first, our group aimed for the lightest and simplest truss. However, because of framework’s results, we had to make some changes. We first changed our cross sectional area. At first, all of our beams were 1x2s, but we decided after analysis to add several 1x4s. In addition to the change in cross sectional area, we added supportive beams at the bottom and in between the diagonal beams and thevertical beams creating a stronger triangular shape. We also decided to increase the height of the truss in order to make our diagonal beams more vertical. We made the change in order to increase the strength and support a larger load.
While changing our design we faced some tradeoffs. We had to consider weight, cost and simplicity in all of our design changes. Our improved design was not assimple as the first one, but it was much stronger. We wanted our truss to support a lot of weight, so we added more beams, which increased the overall weight of our truss. In our final design we also needed more cuts, so our final truss it was more expensive than our initial design. For our final design, we had to sacrifice weight and cost of the truss to obtain the highest possible strength toweight ratio. At first, we wanted to go for the lightest and simplest design, but at the end we ended up with a heavy and stronger truss which was more complex than the first one, but still it was relatively cheap compared to the other groups’ designs.
After agreeing on our final model we had to create a drawing using the computer program “PRO-E”. With the help of the program we were able to...