The influence of cooling hole arrangement on the tensile mechanical properties and damage evolution behavior SiC_f/SiC composites

SiC_f/SiC composites are widely used in hot-end components of aerospace engines. In order to meet the service requirements, a large number of cooling holes need to be processed. However, the arrangement spacing of these holes will weaken the mechanical properties of the components and affect their fracture behavior. The influence pattern of this critical parameter on material failure behavior remains unclear. Tensile experiment and digital image correlation (DIC) technology are adopted to study the influence of hole arrangement spacing on mechanical properties and tensile fracture process, it is found that the tensile strength of the material decreases with the decrease of hole spacing. When the spacing is small, fracture initiates from the hole edge and propagates along the nearest hole. This is attributed to the dense arrangement of holes, where cracks induced by stress concentrations at different hole edges readily interconnect. Moreover, during hole drilling processes, the continuous fiber bundles are sheared, disrupting stress transfer pathways, resulting in a significant decrease in the tensile properties of the material. The influence of hole spacing on different stages of the material fracture process was analyzed by tensile simulation and DIC technology. It was found that the initial damage was generated from the edge of the hole and propagate perpendicular to the loading direction until connecting with adjacent holes. Throughout damage evolution, the maximum stress gradually transferred from the edge of the hole to the interior of the material until the material fracture occurred. This study reveals the correlation mechanism between hole arrangement spacing and mechanical properties and fracture behavior, which provides an important reference for the arrangement design and processing of cooling hole in such materials.