In-plane material continuity for the discrete material optimization method

When performing discrete material optimization of laminated composite structures, the variation of the in-plane material continuity is typically governed by the size of the finite element discretization. For a fine mesh, this can lead to designs that cannot be manufactured due to the complexity of the material distribution. In order to overcome this problem, engineers typically group elements together into socalled patches which share design variables. However, because the shape and size of a patch are fixed during the optimization procedure, a poor patch layout may drastically limit the design space, resulting in suboptimal designs. In this work, in-plane material filters are applied for controlling the material continuity. Here, the engineers can specify a minimum length scale that governs the smallest variation in the material. With this approach, the optimizer is free to determine which material to apply together
with its shape and location.