针刺C/C复合材料高温力学性能试验及本构关系（英文）

High-temperature mechanical properties testing and constitutive relation of needle-punched C/C composite

为研究针刺C/C复合材料高温下力学性能,通过C/C材料试件不同温度下的拉伸、压缩及剪切性能试验,观察试件在高温和外载荷作用下的破坏模式,获得了材料不同温度下的应力-应变曲线。基于对Jones-Nelson-Morgan模型改进并引入温度系数,建立了C/C复合材料高温本构关系模型,并与试验结果进行了对比。结果表明,在温度≤1800℃,针刺C/C材料为线弹性本构关系,C/C材料拉伸、压缩及剪切强度均随温度的升高呈先升高、后降低趋势,在温度≥1600℃后,强度逐渐降低;建立的高温本构模型计算结果与试验结果吻合较好; C/C材料整体表现为脆性破坏,拉伸破坏纤维拔出尺寸较短,压缩破坏断口呈现45°豁口。

In order to study the high-temperature mechanical properties of needle-punched C/C composite,the tests of tensile,compress and shear at different temperatures on C/C composites have been conducted.The failure modes of C/C samples under hightemperature and external loads have been observed,and the stress-strain curves at different temperature are also obtained.Based on the improvement of Jones-Nelson-Morgan model and the introduction of temperature coefficient,a C/C constitutive relation model was established and compared with the testing results.The results show that,at the temperature less than 1800 ℃,the needlepunched C/C material follows a linear elastic constitutive relation,and the tensile,compressive and shear strengths increase first and then decrease with increase of the temperature.The strength decreases gradually when the temperature is above 1600 ℃.The calculated results from a constitutive model are in good agreement with the experimental results.The overall performance of C/C materials is of brittle failure,and the pull-out size of tensile failure fiber is short,whereas the compression fracture presents a 45°notch.