The strain monitoring of automobile tires in-service is quite effective to improve reliability of tires and design tools. The conventional strain gages are cumbersome for the strain measurement of the tires because of their high stiffness and lead wire requirement. In the present study, a new strain measurement system utilize electric capacitance change of steel wire reinforced, low cost wireless sensor built-in tires is proposed and experimentally investigated. A small oscillating circuit in which the capacitor is composed with the rubber and the wire is embedded in the tire, then deformation of the tire causes change of the capacitance makes change of frequency. Measurement of the frequency enables us a remote measuring of the strain of the tire. A rectangular specimen cut from a truck tire is adopted as a specimen. Using the commercially available tire in which sensor embedded, dynamic test is performed and frequency change of the oscillating circuit is measured during the test. As a result, the method is experimentally proved to be effective for the wireless strain monitoring of tires.

抄録全体を表示

In order to improve the oxidation resistance of C/C composites, an inhibitor mixing method was examined in this study. Combinations of oxidation inhibitors, B₄C, SiC, and ZrB₂ at various mixing ratios were tested in the temperature range from 800 to 1, 700°C. In an optimum mixing ratio, the inhibitor-mixed carbon showed superior oxidation resistance up to 1, 700°C. To understand under-lying mechanisms to yield such superior behavior, oxidation behavior of the inhibitor-mixed carbon materials were examined by measuring mass loss rates at various temperatures. In addition, the cross-sections of the as-fabricated and oxidized materials were observed with various microscopes. Based on these experimental results, it was concluded that the chemical interactions among the three inhibitors played important roles to yield the superior high temperature oxidation-resistance.

抄録全体を表示