ISSN:
1013-9826
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
In the subsurface damage observations on the wear behavior of brittle dental porcelains,it still remains unsolved that how to distinguish the cracks that develops accidentally during thepreparing sample process from those actually produced in the tests. In the sliding friction tests, thebonded-interface technique (BIT) was successfully used for subsurface damage evaluations. Theprofile of wear scar was easily observed on the cemented section of the blocks without inducing anycracks. The stresses on the surface and internal of dental porcelains were calculated with the contactelement method (CEM) by ABAQUS software. The model of rectangular dental porcelain and Si3N4ball were developed based on sliding friction tests. The Si3N4 ball modeled in this study was of thediameter of 4mm and 12 mm. The size of Vita VMK 95 porcelain blocks was 5 mm wide, 2 mmthick and 15 mm long. The glue layer thickness values are 10 .m, 20 .m and 30 .m. The loadingof the Si3N4 ball was modeled as a constant distributed vertical load applied across the bonding lineof the porcelain. Stresses and displacements of all nodes of the model, especially at the bondinginterface, were analyzed and compared. The results of the study indicated that stress valuescorrelated strongly to the applied loads. Stress distribution was symmetric about thebonded-interface plane. The maximum occurred in surface layer and the minimum on the bottomline in the porcelain blocks. Along the interface, stresses decreased with the distance from thesurface of porcelain. On the other hand, high stresses focus on the surface part and go sharply downin the internal region along the depth direction. Among the parameters of sliding test on the stresses,the load effect is prominent. The BIT model experiences a different, non-axisymmetric stress fieldthan that of real work-piece. So the BIT should not be considered as a reliable source of quantitativeanalysis but as a qualitative method for observing the form of the damage modes with more visibleinformation than the conventional tools
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/55/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.353-358.864.pdf
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