High temperature dynamic compression mechanical behavior of 3D woven carbon/carbon composites

This study investigates the dynamic compressive mechanical properties of three-dimensional woven carbon/carbon composites under both room temperature（25 ℃） quasi-static and from 25 ℃ to 900 ℃ dynamic compression conditions using both a materials testing machine and a split Hopkinson press bar device equipped for simultaneous high-temperature loading. The experimental results reveal that the strength of the composites is influenced by three key factors： fiber orientation， strain rate， and temperature. Specifically， under consistent strain rates and temperatures， the composites exhibit higher strength in the Z-direction compared to the XY-direction. As the strain rate escalates， the strengths of the composites in both the XY-direction and Z-direction increase， indicating a positive correlation with the strain rate. Upon heating from room temperature to 900 ℃， the strengths of both XY-direction and Z-direction composites initially rise， peaking at 600 ℃， and then gradually decline. Under both static and dynamic loading conditions， XY-direction composites undergo shear failure， albeit with a smaller shear fracture angle in the dynamic case compared to the quasi-static scenario. An increase in the strain rate results in a transition in the fracture mode of Z-direction composites， shifting from shear failure to a combination of matrix crushing and partial fiber fracture.