Papers by Keyword: SCF

Abstract: The paper undertakes the issue of the influence of mesh morphology near the notch on FEM anaysis accuracy. During analyses proposals of free meshes and proposals of mapped meshes have been compared. During the calculations it has been specified how, along with the change of finite element size, mesh quality parameters and stress error change. Selected parameters have been set with values of stress concentration factor. The accuracy of K_t calculations specified during FEM analysis has been compared to other methods.

Abstract: Red phosphorus microencapsulation flame retardant was prepared by Supercritical Fluid-Rapid Expansion of Supercritical Solutions (SCF-RESS),using a self-made special nozzle. The influences of the reversed gyrator, and the rotation angle of the front revolvable tie-in on coating effect were discussed. The results showed that the coating effect which the reversed gyrator was installed on the nozzle was better than it which the reversed gyrator was not installed on the nozzle.The coating effect is the best when the rotation angle of the front revolvable tie-in is 10°,and the coating effect is worse when the rotation angle of the front revolvable tie-in is exceed 10°.

Abstract: A Standing Contact Fatigue (SCF) test set up has been developed in order to facilitate quick testing of contact fatigue resistance of material surfaces. In this method the sample is pressed against a hard ball rapidly and the resulting crack formation is studied in order to evaluate the SCF resistance. Induction hardened surfaces of cam-ring steel and steels with pearlitic, martensitic, bainitic, ausferritic and quench and tempered microstructures have been studied. Characterization was performed by optical microscopy, scanning electron microscopy and hardness measurements. Ring-cone cracks were found at the edge of the indentations but inside the indent in the surface hardened cam-ring steel samples. Sectional views revealed that these cracks also grow underneath the indentation. Radial cracks were found in non-surface hardened samples. The test of the SCF resistance of steels with different microstructures showed that the ausferritic microstructures tested shoved better SCF resistance than the quench and tempered samples with similar hardness. A comparison between different tempering temperatures of surface hardened steels showed that samples tempered at the higher temperature 240 °C resulted in better SCF resistance.

Abstract: Using a variety of advanced ceramic materials, a comparison has been conducted of fracture toughness test methods using the single edge vee-notch beam method and the surface crack in flexure method, the latter restricted to optical fractography. Good agreement has been found between the two methods on materials which were amenable to the SCF method. It has further been shown that the SEVNB method can produce reliable results on materials to which the SCF method is not readily applicable.