RESUMO
An ultrasonic guided wave-based cure monitoring technique is developed to estimate cure-dependent anisotropic viscoelastic properties of carbon fiber reinforced plastics (CFRPs). The guided wave propagating in the transverse direction of a CFRP was measured during a cure process and the energy velocity and attenuation were obtained by signal processing. A micromechanics model and transfer matrix method were used to express the energy velocity and attenuation as functions of only the complex Young's modulus of the resin. The complex Young's modulus of the resin was estimated from the measurement results using response surfaces of the relationship between the energy velocity, attenuation and the resin complex modulus. It was verified that the estimated storage modulus and loss modulus showed reasonable values and behavior. The development of the anisotropic viscoelastic property of CFRPs can be fully determined in real time using this technique.
RESUMO
The new Japanese x-ray astronomy satellite, ASTRO-H, will carry two identical hard x-ray telescopes (HXTs), which cover the energy range of 5 to 80 keV. The HXT mirrors employ tightly nested, conically approximated thin-foil Wolter-I optics, and the mirror surfaces are coated with Pt/C depth-graded multilayers to enhance the hard x-ray effective area by means of Bragg reflection. The HXT comprises foils 120-450 mm in diameter and 200 mm in length, with a focal length of 12 m. To obtain a large effective area, 213 aluminum foils 0.2 mm in thickness are tightly nested confocally. The requirements for HXT are a total effective area of >300 cm2 at 30 keV and an angular resolution of <1.7' in half-power diameter (HPD). Fabrication of two HXTs has been completed, and the x-ray performance of each HXT was measured at a synchrotron radiation facility, SPring-8 BL20B2 in Japan. Angular resolutions (HPD) of 1.9' and 1.8' at 30 keV were obtained for the full telescopes of HXT-1 and HXT-2, respectively. The total effective area of the two HXTs at 30 keV is 349 cm2.