A Parametric Evaluation of Hardness, Compression Set, and Compression Stress Relaxation On O-Rings and Cylindrical Shapes Over a Range of Sizes

There are interests or concerns about the relationship between the material response and the configuration effects when evaluating different materials in a range of different shapes. Although tests such as Shore A Hardness are normally run on an ASTM buttons, samples of interest or concern can come in a range of shapes and sizes. The concern with this test is: How much of the measured response is a material response, and how much is a result of configuration effects? Different kinds of materials, shapes, and test configurations will be evaluated and compared. Additionally, the Compression Set Test is often used to evaluate the state of cure and the sealing capability of materials. A concern with this test is that depending on the sample (material and state of cure), different values can be determined based on the part size and shape. This raises the question as to why the values should vary, and do the differences in the values suggest differences in sealing capability? Different kinds of materials of different shapes and sizes will be compared for their Compression Set response. These samples will also be checked for their Compression Stress Relaxation (CSR) response for comparison. The objective of these kinds of tests are to begin to try to define the capabilities and limitations of these tests, to note: What part of the response is a material response and what is a result of configuration effects, so accommodations can be made for QC purposes, and judgments can be developed related to the anticipated performance in applications?