Fluorescence method was used to detect the micro-damage caused by fatigue in a plain-woven carbon fiber reinforced polymer (CFRP). Fluorescence measurement is a method which estimates micro-damage by measuring fluorescent intensity change inside materials. The principle is, larger micro-damage means larger plastic strain, thus more space in that damaged spot which allows more fluorescent dyes coming in the material. By detecting fluorescent intensity in CFRP layer by layer using confocal laser microscopy, micro-damage can be estimated. Results show that there’s a good relationship between micro-damage and fluorescent intensity gradient.
Functional polymer composite is expected to be applied to the potential material for space deployable structures.
Especially, thermally-activated shape-memory polymer (SMP) composites are increasingly investigated due to their
excellent shape fixity and shape recovery; the thermomechanical properties of these materials greatly change around
their glass transition temperature Tg. To enhance the ability of space deployable structures, the microstructural design at
the fiber-matrix level in the material is required to pursuit the better performance of SMP composite. The present study
focused on a micromechanics consideration of shape-memory polymer (SMP) composite with slits in the fiber mat, and
attempted to discuss the effect of microstructural heterogeneities (slit positions) on the shape-fixity and shape-recovery
performance. Analysis of the shape-recovery performance of SMP composites was conducted using the micromechanical
model based on a viscoelastic thermomechanical constitutive model. According to the numerical results, only when the
slits gather at the same location, the best shape-fixity property and shape-recovery performance is achieved, while
sacrificing its bending stiffness. This is because the slits act as a hinge in the material under a bending loading.
Proc. SPIE. 5138, Photon Migration and Diffuse-Light Imaging
KEYWORDS: Signal to noise ratio, Optical properties, Tissues, Scattering, Optical coherence tomography, Light scattering, Interference (communication), Multiple scattering, Monte Carlo methods, Signal detection
The optical coherence tomography (OCT) has been successfully applied to diagnostic imaging of transparent ocular organs. In case of highly scattering tissues such as skin and mucous membrane, and the OCT signal includes noise component due to multiple scattering in tissue, the characteristics of the OCT signal from the highly scattering tissue is more complex. In this study, we investigate the characteristics of the OCT signal from the low-scattering and highly
scattering tissues by Monte Carlo simulation. In case of low-scattering tissue, the intensity of the signal is maximised when the focal depth equals the probing depth and the spurious peak of the noise due to scattering is observed at the focal depth in the OCT image. In case of highly scattering tissue, the intensity of the signal is maximised when the focal depth is smaller than the probing depth and the noise is almost independent of the focal depth.