Drop-shatter test results

It is sometimes cliflicult to detect nitrogen by the sodium test. The result should not be regarded as conclusive, especially if the substance is volatile, unless it has been dropped in small quantities at a time into the melted metal, which should be heated in a hard-glas.s tube clamped in a retort-.stand. Special care must be used with nitro compounds, which may explode and shatter the Lube. 

We test the impact resistance of polymer plaques using the configuration shown in Fig. 8.8. We subject circular injection molded plaques to the shock of a falling weight with a hemispherical impacter. This test is also known as the Dart Drop Test . Samples can fail in a brittle or a ductile manner. Brittle samples often shatter. Ductile samples can split or a small disk may be punched out of their center. This test provides results that are analogous to those obtained from un-notched impact beam testing. 

Break the test tube carefully in a waste container, and describe in TABLE 32.1A1 how Lucite compares with the starting material. Test the solubility of Lucite in water, and drop a piece of it on your desktop to see if it shatters easily. Describe your results in TABLE 32.1A1. 

The glass mat at the core of the STX sheet was shown to impart some very unusual impact properties to the material. The testing performed in the laboratory (Gardner drop test) and the field results from production components have shown that, in contrast to glass reinforced plastics, the failure mode is elastic rather than brittle. The resultant damage is a hole with little or no crack propagation around the impact area whereas the other reinforced materials will shatter under similar conditions. The STX failure mode applies not only at room temperature, but is equally valid at -40°F. STX impact resistance increases with the thickness of the material, i.e., V4 in. thick plate will resist much higher impact loads than Vs in. thick plate. 

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