A statistical approach to evaluate the influence of geometric parameters on fracture of the cell walls in porous aluminum alloy

During compression of porous metals with unidirectional pores, fracture of cell walls need to be suppressed since it leads to stress drop. However, the occurrence of fracture can not be predicted by only the shape of the cell wall which indicates the complexity of the phenomena. Thus, this research aimed to reveal what geometric parameters affect the fracture and predict them from the initial geometry. Numerical simulations of compression tests were performed for 11 different geometries with the finite element method. The occurrence of the fracture in the range from 0 to 30 pct in compressive strain was obtained and combined with a total of eight geometric parameters for 568 cell walls. Applying a support vector machine showed approximately 0.7 in the F₁ score which suggests a high dependency of fracture on initial geometry. A logistic regression model was also applied to see what parameters are dominant. The results showed cell walls that have small relative thickness, small angle, are connected to cell walls with larger angles, and are located near the side surfaces, are more likely to fracture. Suppression of the fracture was further demonstrated with this by placing cell walls with large relative thickness near the side surfaces.