2D-C/SiC复合材料开孔试件拉伸特性和失效分析

Tensile Properties and Failure Analysis of 2D-C/SiC Composite Laminates with Circular Holes

通过对2D-C/SiC复合材料4mm和6mm开孔试件进行拉伸试验,研究了开孔试件的拉伸特性和失效模式,与标准试件拉伸试验结果比较获得了开孔尺寸对试件强度的影响。相比于标准拉伸试件,4mm和6mm开孔试件的拉伸强度分别减小了1.0%和6.6%。通过在开孔试件不同位置粘贴应变片,获得了试件在拉伸过程中最小净截面上的应变变化规律,直观地体现了试件拉伸过程中的应变集中现象,并通过有限元对开孔试件的应变分布进行模拟,模拟结果与试验值吻合较好;通过在试件表面粘贴声发射探头,获得了拉伸过程中试件材料的损伤参量变化规律,反映了试件的宏观损伤演化规律,并结合试件断口照片分析了开孔试件的失效行为。

Tensile properties and failure modes of the Φ4mm and Φ6mm open-hole specimens of a 2D-C/SiC composite under tensile loading were investigated. The influence of notch size on the open-hole specimen＇s tensile strength was analyzed by comparing with standard specimen＇s experimental results. Compared with the standard specimen, the tensile strength values of Φ4mm and Φ6mm open hole specimens decrease by 1.0% and 6.6% separately. By sticking strain gauges at different locations of the open-hole specimen, the strain variation in the narrowest net section was obtained during the tensile test, and the strain concentration effect was also clearly ex- pressed. Meanwhile, by finite element analysis （FEA） , the strain distribution in the open-hole specimen was simulated. The FEA resuits have good consistence with experimental data. By Acoustic Emission （AE） measurement, the damage evolution of the notched specimen was derived. The AE parameters reflect the macroscopic damage process of the open-hole materials. Combined with fracture section observations, the failure behavior of the open-hole specimens was concisely discussed.