FW圧力容器の力学的特性(耐圧強度)

抄録

The fiber reinforced composites made by use of the filament-winding technique is useful for convex pressure vessels because of their many advantages such as high specific tensile strength etc. In the past developments, the netting analysis was an analytical tool for theoretical analysis of filament-wound pressure vessels. However, it has been difficult to predict analytically the burst strength after initial failure in pressure vessels which have arbitrary dome shapes with variable thickness and fiber orientation along meridian coordinate. In the present paper, the finite element method is used to analyse the mechanical characteristics of FW pressure vessel under internal pressure and to predict its burst pressure. The analysis takes into account the bending moment together with stretch-bending coupling effect, non-linear stress-strain relations and finite deflection. It is done by proposing the two initial failure criteria for laminae and the two ultimate fracture criteria for laminated structures. In analysing the ultimate strength, normal moduli transverse to fibers and shear moduli along fibers are assumed to become negative in parabolic functions during unloading after initial failure. The numerical results were obtained by applying the load incremental method to the isotensoid CFRP pressure vessel which was used for the kick-motor case (EXOS-KM-B) to launch the scientific satellite "Zikiken" and they were found to agree fairly with the experimental burst pressure and fracture behaviors.