Study on the effect of porosity on crack propagation

The detrimental effect of porosity in cast turbine and compressor blades has been a major issue since long. Though there has been extensive development in casting technology and the incorporation of advanced strategies to reduce the defects, the complete preclusion of porosity in the cast products has not been achieved. The influence of porosity on the path of propagation of a crack has been studied in this work. Quasi-static tensile simulation was performed on polymethyl methacrylate specimens, using Extended Finite Element Method (XFEM). This was done to observe the changes in the crack propagation path due to the presence of macro porosity. The XFEM results were validated by experimental tensile testing on the same specimens. This serves as a pilot study to understand and predict the path of crack propagation in cast components such as turbine/compressor blades with inherent porosity.