Analytical approach to crack tip plasticity of dental CoCrMo alloy
In this paper, a thin infinite plate of CoCrMo alloy with a straight crack was loaded perpendicularly to the crack plane. CoCrMo alloys are due to their suitable mechanical and corrosion properties widely used for dental applications. The importance of good mechanical properties is reflected in ensuring the functional and technical durability of dental appliances. The intention of this paper is to use a mathematical approach in analyzing a thin infinite plate with a straight crack to the rather complex occurrences within the cohesive zones around the crack tips. The dependence of plastic zone magnitude around the crack tip on an external load of dental CoCrMo alloy plate was considered in this paper. Static tensile tests were carried out to determine the mechanical properties of dental CoCrMo alloy. At plastic deformation, the dental CoCrMo alloy is nonlinearly hardened in accordance with the Ramberg-Osgood equation which parameters were determined using a least-squares method from experimental data. The application of the Dugdale model the plastic zone magnitude around the crack tip was determined. The stress intensity coefficient from the cohesive stresses was calculated using Green functions. The analytical methods, assuming a small plastic zone around a crack tip, were used in the analysis. The results were obtained by means of a commercial software package and presented in the form of diagrams.