  The concurrent optimization of topology and fibre orientation is a promising
approach to pursue higher strength and lighter weight of variable-stiffness
structure. This study proposes a novel discrete-continuous scheme for the
concurrent optimization. Considering the global convergence, Discrete Material
Optimization (DMO) is firstly utilized to select a dominant angle for each
element from several predefined candidate angles. However, it is still
difficult to obtain excellent fibre angle convergence due to difficulty in
selection of candidate materials for some elements. Therefore, the Sequential
Binary-Phase Topology Optimization is proposed to guarantee the uniqueness of
the element to candidate angle mapping. Moreover, to obtain better mechanical
properties, Continuous Fibre Angle Optimization (CFAO) with spatial filter is
introduced to optimize fibre continuity. Several classic numerical examples are
used to verify the excellent performance of the proposed method in terms of
fibre angle convergence and stable optimization ability.
