摘要
通过拉伸、压缩和疲劳实验结合断口显微观察并与光滑试样进行对比,研究开孔对平纹编织C/SiC陶瓷基复合材料力学行为的影响。结果表明:开孔试样的拉伸行为和光滑试样一样表现为非线性,拉伸强度降低11.8%,拉伸破坏应变降低54.3%;开孔试样的压缩行为与光滑试样不同,低应力时表现为线性,应力增大到一定程度时由于裂纹闭合效应较为明显,开始表现出明显的非线性,压缩强度降低12.2%,压缩破坏应变降低54.9%;开孔试样的疲劳极限约为其极限拉伸强度的88%,与光滑试样相同;开孔试样在拉伸、压缩和疲劳载荷作用下都具有较小的应力集中系数,对开孔敏感性较小;开孔试样断口一般从孔中间穿过,破坏首先发生在试样孔边应力集中最严重的地方,断口方向与孔边初始缺陷有关。
Tension, compression and fatigue experiments were performed to investigate the mechanical behavior of plain-woven C/SiC composite specimen with open hole compared with that of smooth specimen. The fracture surfaces of specimens were observed by scanning electron microscope（SEM） and optical microscope（OM） to analyze its damage mechanism. The results indicate that, the response of plain-woven C/SiC ceramic matrix composite specimen with open hole under tensile loading is nonlinear to rupture and the same as that of smooth specimen, tensile strength decreases by 11.8% and tensile fracture strain decreases by 54.3 %. The response of specimen with open hole under compression loading is different from that of smooth specimen, it is linear at low stress level and then becomes nonlinear due to obvious crack closure effect. Compression strength decreases by 12.2% and compression fracture strain decreases by 54.9%. Fatigue limite of specimen with open hole is 88% of its ultimate tensile strength and equivalent to that of smooth specimen. The specimen With open hole has low stress concentration factor and hence has low sensitivity to open hole. The fracture surfaces all go across the center of open hole. Damage appears at the hole edge where has severe stress concentration effect. The direction of fracture surface is related to the initial imperfection of open hole.
出处
《材料工程》
EI
CAS
CSCD
北大核心
2009年第9期71-74,共4页
Journal of Materials Engineering
基金
国家自然科学基金资助项目(10372081)
