针刺C/ C 复合材料剪切性能

利用V形开口梁(Iosipescu)实验对一种新型针刺准三维C/C复合材料面内剪切性能及层间剪切性能进行了测试分析;获得了离散性较小的剪切强度与剪切模量值,以及有效地破坏模式;同时用有限元方法分析了层间剪切试样中的应力分布状态。结果表明,试样缺口根部处应力集中引起试样过早破坏,人为引入缺陷后,可以得到较均匀的剪应力场。

Shear properties of needled felt carbon/ carbon composites

A new designed quasi-3D needled felt C/C composites have been tested to measure both in-plane shear and interlaminar shear properties by the Iosipescu shear method.The results of both stresses and moduli have shown small scatter,and invalid failure modes were obtained.The interlaminar shear V-notch specimen was analyzed using the finite element method to find out how the stress and strain fields distribute in the test section.The study shows that,the stress concentrations near the notch roots have caused premature failures of the sample.When two cracks are introduced,a homogeneous shear stress state is achieved.