抄録
It is postulated that yielding of roving glass cloth FRP depends only on the shear stress component τ12 in the principal axis of anisotropy and the yield criterion for the material is expressed as τ12=τy (constant).
By using this criterion the elastoplastic behavior under uniaxial tension of an anisotropic plate with a circular hole has been studied by means of the finite-element method.
The results obtained are as follows:
(1) In the case of 0 degree tension, the angle θ where the shear stress τ12 becomes maximum is about 62∼72 degree. The yeilding zone starts at this point and grows to 0 degree direction. The nominal stress level σ0y when the material begins to yield is about 1.23 τy in the case of an infinite plate.
(2) In the case of 45 degree tension, θ is always 90 degree and the yielding zone grows to 45 degree direction. σ0y is 0.74 τy for an infinite plate.
(3) The stress concentration factor increases when the yielding zone grows.
