Multiscale Analysis on Three‐Dimensional Heat Transfer of Needle‐Punched Composite Preforms: Virtual Fiber Models and Layered Homogenization‐Reintegration Method

Accurate virtual fiber component models of needle‐punched quartz fiber felt/fabric composite preforms (NQFFCP) are constructed, including needle‐punched fiber bundles along thickness direction (NFBATD), fiber felt and fabric models. Micro‐CT technology is used to quantify geometric structure of NQFFCP and its component materials. Based on this, a comprehensive “layered homogenization‐reintegration method” is proposed to construct 3D finite element (FE) heat transfer models of NQFFCP at different needle‐punched densities (NDs). A Hot‐Disk thermal analyzer is utilized to measure the anisotropic thermal conductivity (ATC) of materials. Additionally, 3D temperature and heat flux distributions of NQFFCP at different NDs are simulated, and their ATC are predicted. Furthermore, temperature and heat distribution characteristics are simulated and studied at multiscale. At fiber‐scale, effects of yarn interlacing and fiber orientation on heat flux distribution are analyzed, while the influence of NFBATD on heat transfer in felt and fabric layer fields is demonstrated. Finally, the correlation among NDs, ATC and NQFFCP structure variety is analyzed and revealed through FE and experimental methods.