How to design a blockage-tolerant cooling network?

•HyTopS optimization by considering blockage is developed for microvascular composites.•HyTopS provides nature-inspired network redundancy to rise uniformity of temperature.•Importance Factor (IF) method is proposed to predict the worst-case blockage scenario.•Computational cost is reduced by using IGFEM, reduced-order thermal model, and IF.•Various optimization schemes for blockage is compared in terms of cost and accuracy. Nature-inspired microvascular composites rely on microchannel networks to enable a variety of multifunctionality including self-healing and active cooling. However, the small size of the microchannels makes them highly susceptible to blockage from the presence of particulates in the fluid or damage in the vascular network. Blockage in the microchannels may disrupt the functionality of the microvascular composites. As an effort to alleviate the destructive effects of microchannel blockage, we present a Hybrid Topology/Shape (HyTopS) optimization approach to design actively-cooled microvascular networks for blockage tolerance. The proposed method shows a promising capability in producing a reliable design for blockage tolerance. In this hybrid scheme, the optimizer can modify the topology of the design during the shape optimization procedure. Being able to change the topology of the network enables the optimizer to provide network redundancy to effectively optimize the design for blockage tolerance. In this scheme, the optimizer takes into consideration the blockage scenarios in each iteration. As a result, the design will be optimized in such a way that it would perform satisfactorily when blockage of microchannels occurs. The main challenge in this method, similar to the other common approaches for blockage tolerance, is the extensive computational cost. To address this issue, we present a novel Importance Factor (IF) method and combined it with the HyTopS approach to reduce the computational cost significantly. For further reduction of computational cost, we use Interface-enriched Generalized Finite Element Method (IGFEM) wherein the design geometry is projected onto a fixed mesh. Thus, there is no need for remeshing during the optimization procedure. Moreover, a fully analytic sensitivity analysis of the shape optimization of the microvascular composites is also developed. Finally, we solve several numerical examples to investigate the pros and cons of using the proposed optimization approaches for blockage tolerance.