Реферат: Balsawood Structure Design Essay Research Paper 1

plastic behavior starts.

Figure 2: Compression Testing Setup

Failure was taken at the yield strength because the material is no

longer behaving elastically at this point and may be expanding outside

of the design constraints. It should be noted that original specimens

proved to be too tall and they failed in buckling (they sheared to one

side), instead of failing under simple compression.

Table 2: Compression Test Results

Specimen # Strength (psi)

1 464

2 380

3 397

Average 414

Under tension, the pieces all had similar strength values. This took

many tests, but in every other test, the material exhibited buckling as

well as compression. The three tests which ran the best were used for

Table 2.

Since the test of the design will be under compression, this data is

very relevant for the final design. Apparently balsa can withstand

approximately 3 times more load under tension than under compression.

However, much like in these test, buckling is likely to occur in the

final design. This fact should be of utmost consideration when

designing the legs of the structure.

Three Point Bending

This test is performed by placing the specimen between two supports,

and applying a load in the opposite direction of the supports, thus

creating shear stress throughout the member. Much like the tension

test, the wood will deform and then break at a critical stress. Figure

3 shows how this test was setup. The data obtained form this test can