Eco-friendly microwave absorption metastructure: Design, optimization, and performance of CPVM based on PLA@CF

To address the escalating issue of electromagnetic interference, creating a metastructure for thin, lightweight, wide, and strong electromagnetic wave absorption is imperative. This paper introduces the Crassula perforate variegate metastructure (CPVM), inspired by the succulent plant Crassula perforate variegate in nature, characterized by its isotropic and broadband absorption performance. Following an eco-friendly design approach, the proposal involves using polylactic acid (PLA) and chopped carbon fibers (CFs) as the matrix material and electromagnetic wave absorber for CPVM, respectively. This achieves lightweight of the metastructure and enhances the load-bearing performance of PLA. The PLA@CF composite material is processed into 3D printing filaments, enabling rapid specimen fabrication and significantly reducing production and development costs. Mechanical tests validate the outstanding tensile and flexural strength (80.5 MPa) as well as remarkable toughness of the proposed PLA@CF composite material. The optimization design of CPVM is efficiently accomplished using the Whale Optimization Algorithm (WOA), Deep Neural Networks (DNN), and Simulated Annealing (SA) algorithm. Reflectivity tests on CPVM reveal an effective bandwidth of 31.64 GHz within the 2-40 GHz frequency range, with a coverage rate of 83.3 %. Additionally, CPVM demonstrates excellent electromagnetic wave absorption capabilities in the S and C bands.