Yoshiyuki YAMAGISHI
Effect of influencing factor on strengthening effect of steel pipe reinforced by CFRP
Takeshi MIYASHITA
Presently, in the repair and reinforcement of thin-walled steel pipe, such as a steel chimney, although the caul plate method is adopted, it has a problem that it's not superior to the construction.Therefore, to improve the efficiency of construction , the development of a method to repair the thin-walled steel pipe that local buckling occurs by using the carbon fiber sheet are underway .By this method is established, recovery to the original mechanics performance design , or performance improvement of is expected .However, it has not been studied effect of reinforcing effect and fiber orientation relationships and thermal stresses of varying the fiber direction of the carbon fiber sheet.
In this study, for the establishment of the carbon fiber sheet bonding method for thin cylindrical shell structure, through the heat stress measurement test and compression test carry out a study about the impact factor for the reinforcing effect.Specifically, local buckling is bonded surely changing the fiber orientation angle of carbon fiber sheet in steel circular tube of thin to generate, the improvement of the compression load-bearing capacity to suppress the occurrence of local buckling of thin-walled steel pipe attempt.In addition, the temperature change is carried out heat stress measurement of the carbon fiber sheet reinforced steel pipe in the range of 20 ¡î ~ 80 ¡î, to assess the direction and magnitude of thermal stress .
Thermal stress measurement test results, the relationship in the direction and size of the thermal stress that occurs when the fiber orientation angle has been confirmed.The size of the heat principal stress due to the influence of fiber orientation has been found that it is possible to simply determinable by use of the thermal stress calculation formula and fiber orientation of the past, the direction of the main stress.
The size of the heat principal stress due to the influence of fiber orientation has been found that it is possible to simply determinable by use of the thermal stress calculation formula and fiber orientation calculation formula, the direction of the main stress.Reinforcing effect was obtained by improving the rigidity and toughness. When the fiber orientation angle is 0 ¡ë, the stiffness became maximum. Also, when the fiber orientation angle is 90 ¡ë, the toughness became maximum. Further, if the fiber orientation angle 0 ¡ë and 90 ¡ë is combined with carbon fiber sheet, it was confirmed that it is possible to improve both the stiffness and toughness.Based on this result, assuming a case of three on mechanical properties to be improved, we have proposed for the optimal fiber orientation in each case.
Please use "previous botton" to return the previous page