Concurrent topology and fiber orientation optimization method for fiber-reinforced composites based on composite additive manufacturing

Abstract

Additive manufacturing of fiber-reinforced composite (FRC) parts provides a new rapid prototyping technique for designs. However, restricted by the layer-by-layer style of additive manufacturing techniques, the designed fiber orientations should be parallel to the print plane, and that will result in a reduced design space for the orientation optimization. To enlarge the orientation design space under this constraint, this paper proposes a new optimization method for FRC parts. The optimized structure is composed of several groups of components, and the fiber orientation of each group of components is constrained to a specific plane. Based on the composite additive manufacturing technology, these components can be fabricated separately and joined together to form the whole structure. The number of the component groups (also the fiber print planes) is predefined. In this method, the structure is optimized by concurrently designing the topology, the components partitioning and the fiber orientations. The structural topology and components partitioning are described by the SIMP interpolation scheme and discrete material optimization (DMO) interpolation scheme, respectively. The discrete-continuous parameterization (DCP) method with two sub-intervals is applied in the orientation optimization to avoid the local optimum of the angle variables, and a unified formulation is given for the concurrent optimization design. Furthermore, a density projection strategy with self-adaptive threshold parameters for multi-material optimization problems is proposed to get the distinct component interfaces. A stable convergence can be obtained without manually adjusting the projection parameters during the optimization iterations. The corresponding angle filtering method is developed to smooth the optimized fiber orientations. Numerical examples and manufacturing experiments are presented to demonstrate the effectiveness of the proposed method.