缝合式三维编织C/SiC复合材料拉伸加卸载力学行为

本文通过开展缝合式三维编织C/SiC复合材料的准静态单轴拉伸及循环加卸载试验，研究加卸载行为对复合材料的损伤及材料内部能量耗散的影响。通过对材料的断口分析，探究加卸载对材料破坏强度的影响规律。结果表明，加卸载行为会消耗材料内部的能量，对纤维束与基体之间的界面造成损伤，进而降低材料的承载能力；材料滞回曲线的面积随着卸载点应力的增大而增大；材料的整体失效属于脆性破坏，复合材料断口表现出明显的分层现象，且单轴拉伸时断口相对于循环加卸载更整齐。 

Mechanical behavior of sutured 3D-C/SiC braided composite under cycle tensile loading

Quasi-static uniaxial tension and cyclic loading/unloading tests of the sutured 3D-C/SiC braided composites were carried out to research the effects of cycle loading/unloading behavior on the damage and inner energy dissipation. Through the fractography analysis of this material, the effect law of the strength change caused by cycle loading/unloading has been explored. The results show that the behavior of cycle loading/unloading will consume energy of interface between matrix and fiber bundle inside the material, resulting in damage to it, which reduces the load-bearing capacity of the material, and the area of hysteresis loop increases as the stress of each unloading point increases. The overall failure of this material is brittle failure, but the fracture of the sample shows obvious delamination under monotonous loading and cycle loading, while the fracture of the uniaxial tensile specimen is more uniform.