Design and fabrication of 2.5D Janus hybrid woven SiCf/SiC metamaterials for broadband absorption and high load-bearing

SiCf/SiC composites have been widely used in hot end parts of aircraft because of advantages of high strength, high temperature resistance and oxidation resistance. However, their narrow-band electromagnetic (EM) waves absorption features limit the realization of structure-function integration. To break this limitation, a 2.5D Janus hybrid woven SiCf/SiC absorbing metamaterial (JHWMM) composed of three different permittivity SiC fibers is proposed, and the genetic algorithm is used to optimize the thickness and permittivity of each layer. Further, the absorption properties and mechanisms were studied by combining experiment and simulation. Compared with the 2.5D woven SiCf/SiC composite composed of only a single permittivity fibers, the effective absorption bandwidth (EAB, 11.2 GHz) of the JHWMM is increased by 2.7 times, and the average reflection loss (RL, -12.4 dB) increased by 1 times. Its excellent absorbing performance is attributed to the synergistic effect of strong structural loss, dielectric loss and excellent impedance matching. In addition, the JHWMM also exhibits good wide-angle (0 degrees-40 degrees) absorption characteristics and excellent load-bearing properties (the bending strength is 222.3 MPa). The 2.5D Janus hybrid woven structure proposed in this study provides an important reference for the development of high-bearing, wide-absorbing and high-temperature absorbing materials for a new generation of aircraft, and has important engineering application value.