In this study, we have proposed and implemented a profile measurement system for microholes using an optical fiber probe equipped with a vibrating mechanism driven by a piezoelectric element. The optical fiber probe consists of a stylus shaft of 3 µm diameter and a glass ball of 5 µm diameter attached to the tip. The principle involves the monitoring of the stylus shaft displacement by detecting a change in the amount of light received by two dual-element photodiodes. These diodes are set up facing laser beams that are irradiated onto the shaft portion from the X and Y directions. In this study, a tube-type piezoelectric element was set at the base of the stylus allowing it to vibrate in the X and Y directions. Firstly, we examined the displacement detection characteristics and frequency response characteristics of the probe. Secondly, the performance of the vibrating mechanism was examined. Finally, the measurement performance of the fiber probe was experimentally examined by measuring a hole of 150 µm diameter. The stylus could be operated in a circular path of 9.69 µm diameter. The changes in amplitude and phase of vibration of the stylus allowed for contact detection with the hole wall. Our study has potential applications for measurements of microholes in the diameter range of 10-150 µm.
Pressure vessels made of carbon-fiber-reinforced plastic (CFRP) materials are mainly used for hydrogen storage in fuel-cell vehicles and are manufactured by filament winding (FW). However, the FW method requires the use of an expensive autoclave; furthermore, the fiber strength decreases because of the tension induced in the fibers during lamination, and there is excessive discharge of resin during the fabrication process. To solve these problems, we developed a machine based on the fiber-reinforced plastic (FRP) manufacturing method; in this machine, filament winding is carried out by heating the inner surface of a liner. We fabricated trial CFRP vessels using this machine to show that the CFRP material can be laminated and cured simultaneously. In our method, the quantity of fibers per volume in CFRP increased, and a decrease in a nonbonded area between CFRP layers was observed. Moreover, the vessels produced by the proposed method had higher stiffness and 12-39% higher strength than those fabricated by conventional methods.
In this paper, the solution for the hollow cylindroid is analytically derived under two assumptions that (1) the cylindroid is consist of various anisotropic elastic material and (2) only both sides of the hollow cylindroid are subjected to arbitrary load, which will be expanded to complex form of Fourier series with period 2. To simplify an analysis, mapping function, which is mapped elliptical boundaries of the cylindroid to unit circle, and complex stress functions proposed by S. G. Lekhnitskii are introduced. These stress functions have undetermined coefficients, however, these coefficients can be determined by taking into account the boundary conditions for resultant stresses at both sides of the hollow cylindroid. In particular, undetermined coefficients in stress functions will be determined by comparing with complex Fourier coefficients for those resultant stresses. In the case of isotropic cylindroid, analytical solution for similar problem was already derived, however, there is one limit of application. This limit is related to the cross-sectional shape of hollow cylindroid. That is, if both sides of the hollow cylindroid did not have a same focus of an ellipse, analytical solution for isotropic case was not able to derive. On the other hand, the solution derived from this study does not have such a limit. So some numerical examples are shown by some figures and tables not only anisotropic case but also isotropic case.
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