Stress Redistribution in Cellular Lattice Structures with Cell Wall Damage

摘要

This paper studies the behavior of hexagonal cellular lattice structures with a broken cell wall under uniaxial extension along the principle directions. A 3-D Finite-Element model is developed in ABAQUS 6.13 to represent a section of the lattice around the damaged wall, and the change in stress in the nearby walls due to the load redistribution process is examined. Simulations are conducted for three different values of cell angles (0 = 15,30 and 60 deg). When an inclined wall is broken, very large increases in bending-induced axial stresses are observed in the two adjacent vertical walls during load redistribution. For loading in the y-direction (aligned with the vertical walls), this phenomenon is more pronounced for lower (shallower) cell angles, and the converse is true for loading in the x-direction. When a vertical wall is broken, an applied extensional load in the y-direction results in an increase in extensionally-induced axial stress in the two adjacent vertical walls, an increase in bending-induced axial stress in the closest vertical walls in adjacent chains above and below the damaged wall, and an increase in bending in the inclined walls connecting these vertical walls, in the load transfer process. This phenomenon is more pronounced for shallower cell angles. Damage in vertical walls has no effect when the applied load is in the orthogonal (x) direction.