抄録
The deformation characteristics of metallic materials under the single axial tensile testing are analyzed by an upper bound method based on the theorem of plasticity using R. Hill's orthogonal anisotropic yield criterion. This method was applied to estimate the deformation behavior of a GFRP sheet, combining the r-value as an estimate of plastic workability on orthogonal anisotropic metallic materials. The difference in strength between woven and laminated sheets is considered to be caused by the fiber to fiber friction, and this is calculated on a woven sheet using a unit model. Measuring the orientation angle and the elongation of fiber, the relation between the r-value and fiber orientation was evaluated.
It was concluded that these concepts can be effectively applied to the estimation of plastic workability.
