Balsawood Structure Design Essay Research Paper Balsawood

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Balsawood Structure Design Essay, Research Paper Balsawood Structure Design1. Introduction:This report is the first stage of the design, construction and testingof a balsa wood structure. In April, the design will be tested againstclassmates designs, where the design with the highest load/weight ratiowins. The information gained from this report will be used in theconstruction of the structure. The report is composed of two sections.The first is an evaluation of material properties of balsa, glues anddifferent joint configurations. The second section consists of adiscussion on a preliminary design that is based on conclusions drawnfrom the testing section. Common material tests of tension, compression and bending wereperformed and analyzed. The qualities of three different

adhesives weretested and evaluated, and finally, three different joint configurationswere tested. Illustrations of each test setup are included. Wheneverpossible, qualitative results will be given as opposed to strictlyquantitative values. A qualitative result is much more useful ingeneral design decisions. Experimental results from the testing stagecombined with experiences is working with the materials offered cluesfor the preliminary design. The design section mixes both practical and experimental experiencetogether to present the best possible solution for the structure. Italso offers additional insights that were not considered in the initialmaterial testing procedure. The design presented in the this section,is likely to be similar the final model, however modifications may

beneeded for the final design that were unforeseeable at the time of thisreport. This report generally functions as a guide for the construction stage ofthe project. Its role is to provide useful information and a basis forthe final design. Before the final design is tested, prototypes will beconstructed to test the principles discussed in this report. The goalof this report is to combine the results from testing and experience toproduce a working preliminary design. 2. Material TestingAll standard testing was performed on the Applied Test System located inroom XXXXXXXXXXXXXX. The goal of this section is to determine thematerial strengths of balsa, and how balsa responds to differentloading. Before testing, the basic structure of balsa needs to beconsidered. Wood grain is

composed of bundles of thin tubularcomponents or fibers which are naturally formed together. When loadedparallel to this grain, the fibers exhibit the greatest strength. Whenloaded perpendicular to the grain, the fibers pull apart easily, and thematerial exhibits the least strength.Generally, for design considerations, the weakest orientation should betested. However, testing procedure called for testing of the materialin the greatest strength orientations; torsion and compression, parallelto the grain, and bending with the shear forces perpendicular to thegrain. Testing the materials for their “best direction” characteristicscan produce results that are not representative of real behavior. Toexpect uniform stress distributions and to predict the exact locationsof stresses

prior to testing prototypes is generally not a good idea.However the values obtained from these tests can give a general idea ofwhere the structure may fail, and will display basic properties of thematerial. Tension TestIn tension testing, it is important to have samples shaped like the onein Figure 1, or the material may break at the ends where the clamps areapplied to the material. Failure was defined to occur when the specimenbroke in the center area, and not near the clamps. The machine recordsthe maximum load applied to the specimen and the cross sectional areawas taken of the central area prior to testing. These two values areused to compute the maximum stress the material can withstand beforefailure. Figure 1: Sample Torsion Specimen In general, the material failed at the