十字型ミニチュア試験片を用いた多軸クリープ試験に関する検討

抄録

This paper describes a development of multiaxial creep testing techniques with a small size cruciform specimen. Structural components such as thermal power plant pipe and turbine blade of airplane engine undergo multiaxial loading at high temperature. Although studies of multiaxial loading at high temperature are essential for commercial product development and designing, there is little experimental research on multiaxial creep. Since there is no commercial multiaxial creep testing apparatus, we are trying to develop a biaxial tensile multiaxial loading testing apparatus with a small size specimen. A small size cruciform type specimen was designed for high temperature multiaxial loading by using finite elements analysis. The specimen has 5mmx5mm size square gage area which is designed as stress distribution of the area to be constant. The specimen also has four loading arms for tensile loading. Changing the applied load value to the loading arm, various principal stress ratio λ, which is used for expressing a stress multiaxiality, can be conduct in the range from λ=0 to λ=1. This study also develops a non-contact strain measuring method which uses a conventional optical observation tools. The method can trace a movement path of some small target marks which are painted on the gage area and calculates the strain of the specimen. The strain value obtained from the non-contact method corresponds with the strain gage value.