Stress concentration factors for planar square cell lattices with filleted junctions

The estimation of the fatigue resistance of cellular structures is fundamental in many applications. The maximum stresses in a material determine the fatigue resistance of the component. In this work, a numerical method is proposed for the estimation of the Stress Concentration Factors (SCF) at the cell wall junctions of 2D cellular structures based on square unit cells. The aim is to obtain a model capable of calculating the values of the SCF as a function of the unit cell geometrical parameters, namely the cell-wall thickness t0 and the fillet radius R at the joints. This was achieved by applying the Finite Elements (FE) method to the unit cell for wide intervals of t0 and R to calculate the SCF for each couple of the parameters. The values of the SCFs were then fitted with some functions.