A New Approach to Modeling the Ductile Cast Iron Microstructure for a Finite Element Analysis

In this article, a methodology for the generation of geometric models representing the microstructure of a ductile cast iron (DCI) is presented. This methodology is based on a series of image processing algorithms to extract the graphite nodules contours and the utilization of the Bezier curves to smooth the geometric models curves. For the contours obtained by the image processing stage and generated geometric models, the circularity is calculated using the circular shape factor index, in order to analyze the induced error through the discretization process by the image processing stage and the variation of the circularity as the design parameters of the geometric modeling change. On the other hand, the design parameters effect of the geometric models on the stress behavior in the microstructure, through a finite element analysis, is also analyzed. It is shown that as the Bezier curve degree increases, the circularity of the geometric models decreases, thus increasing the maximum stresses produced in the DCI microstructure. Further, it is also found that the number of interpolation points has a significant effect on the mechanical properties when the Bezier curves degrees are equal to 10 and 12 than for the lower degrees.