斜交積層FW板の二軸引張降伏-破壊則について
1971 年 20 巻 214 号 p. 879-885
詳細
1971 年 20 巻 214 号 p. 879-885
Hereunder is presented the report of studies, both theoretical and experimental, made of the criterion for the yield and fracture of angle ply laminates wound with filament, in their biaxial tension.
Cylinders wound with filament at the angle of 54.75° have been tested in their biaxial tension (σx: axial stress, σy: hoop stress), and interesting facts have been found.
(1) In axial tension (σy/σx=0) the yield strength coincides with the breaking strength, but
(2) In internal pressure (σy/σx=2)
(3) In pure hoop loading (σy/σx=∞)
(4) In stress ratio σy/σx=4}the breaking strength is remarkably larger than the corresponding yield strength.
To explain these experimental facts a new idea of volume effect has been introduced. In the calculation of the stresses of each layer after the fracture of matrix, variations of elastic moduli have been introduced for the open crack case and the close crack case. The theoretical conclusion thus obtained coincides well with the complex experimental results.
