On the tensile behaviors of 2D twill woven SiO_2f/SiO₂ composites at ambient and elevated temperatures: mesoscale analysis and in situ experimental investigation

SiO_2f/SiO₂ composites are among the most ideal high-temperature wave-transparent materials used in hypersonic vehicles. The purpose of the study is the thorough experimental investigation of the tensile behavior of a 2D twill woven SiO_2f/SiO₂ composite, and the establishment of an accurate and efficient simulation method for such composites. The digital image correlation (DIC) method was utilized to capture local deformation data during tensile tests. Meanwhile, a progressive failure analysis (PFA) model employing the exponential damage evolution law was subsequently developed with UMAT in ABAQUS. Simulations of the mechanical properties and strain distributions show good consistency with experimental results. The results at room temperature and 900 °C demonstrate that the strain distributions exhibit obvious periodic patterns related to the woven structure. In addition, band-shaped strain concentrations can be observed at the intersection zones between adjacent longitudinal and transverse fiber bundles. These zones are regarded as critical regions. This was validated by the damage evolution observed in the simulations. Owing to the grain coarsening of quartz fibers and the embrittlement of different constituents at 900 °C, notable degradation of the mechanical properties and brittle fracture characteristics were observed.