Study on shear properties of FRP laminates through the thickness direction under static and imapact loadings

为了使CFRP在轻质结构领域得到更广泛的应用，需要明确CFRP的静态和冲击横向（通过CFRP层合板的厚度方向）剪切性能。虽然横向剪切强度已经报道了使用短梁测试，横向剪切模量和破坏应变，然而，没有报道，因为这些值的测量是很难在experiment.This研究提出了第一个实验获得的静态和冲击横向剪切模量和破坏应变。为了获得这些值，测量短梁试件中性轴上两点的垂直位移差，并除以这两点的距离。为了测量这种差异，我们设计了一种新型的电光引伸计，测量了单向层合板在纤维取向角从0 °到90 °变化时的横向剪切模量和破坏应变的变化，首次证实了横向各向同性。将这些实验模量与基于经典层合理论的解析模量进行了比较，实验值与解析值雅阁。此外，根据纤维取向角的破坏应变的实验结果，第一和它们的破坏模式进行了检查，通过使用超声波C扫描。最后表明，这些故障模式定性同意由三维有限元得到的。

For the wider use of CFRP in the field of light weight structures, the static and impact transverse (through the thickness direction in CFRP laminates) shear properties of CFRP should be made clear. While transverse shear strengths have been reported by use of a short beam test, the transverse shear moduli and failure strains, however, have not reported because the measurement of these values is difficult in experiment.This research presents the first experiment for obtaining the static and impact transverse shear moduli and failure strains. In order to obtain these values, the difference of vertical displacement of two points on the neutral axis of short beam specimen is measured and is divided by the distance of these two points. For measuring this difference, an Electro optical extensometer is newly devised.When the fiber orientation angles of unidirectional laminates is changed from 0ﾟ to 90ﾟ, the variations of transverse shear moduli and failure strains are measured and the transversely isotropy is first confirmed by our experiment. These experimental moduli are compared with the analytical ones based on the classical lamination theory and the experimental values accord with analytical ones. Furthermore, the experimental results of the failure strain according to the fiber orientation angle are obtained first and their failure modes are examined by use of an ultrasonic C-scan. It is finally showed that these failure modes qualitatively agree with ones obtained by a three dimensional FEM.