Date of Award
Master of Science (MS)
Poly(methyl methacrylate, (PMMA) has been implemented as part of the supporting structure in complete hip and knee replacements since the 1950s. Known as bone cement while in the body, PMMA is known to undergo compressive and tensile stresses that wear down the bio-compatible barrier and cause pieces to come loose inside the human body. These pieces are then attacked by the body’s own nervous system, leading to inflammation, and eventually necessitating replacement. It has been documented that under cyclic loading PMMA can reach temperatures that start to degrade its tensile capabilities. In this study the potential cause of self-heating was examined via ASTM D638 type I dog bone samples. These specimens underwent cyclic tension-tension tests run on an Instron 8801 tensile tester at varying frequencies for a total of 10,000 cycles each. Digital image correlation (DIC) was implemented to analyze displacement of the gage section as well as to calculate strain. At the same time thermography images were taken and then compared with DIC to ascertain whether localized strain would be an indicator for any localized thermal activity. The same was done for a second set of tests where a stress concentration, in the form of a 2.78 mm hole was introduced into the center of the dog bone sample.
The introduction of the hole in the specimen highlighted the role that stress concentrators have in self heating. While there was little correlation for the non-holed specimens between concentrated areas of strain and localized thermal activity, the holed specimens correlated extremely well between where the strain had localized around the hole and the self-heating had similarly localized.
Kose, Muhammed R., "Analysis of the Self-heating Effect on Unfilled Poly(Methyl Methacrylate) Due to Cyclic Behavior" (2022). All Theses. 3812.