| 摘要 |
A layout and manufacturing method for fiber-reinforced, laminated composite shells utilizes as a reinforcement a nested assembly of braided sleeves. The original sleeve diameters are selected individually such that, upon being deformed into the final shape, the fibers acquire angular orientations prescribed by the shell design. Shells of desired shapes are obtained either by pulling the sleeves on a rigid mandrel or, alternately, by statically defoming the nested sleeve assembly, thereby eliminating the use of mandrels. The statical means involve proper combinations of tensile edge forces and surface loads exerted, e.g., by a pressurized bladder or by spinning the assembly. In one embodiment, the sleeves are tensioned and, if necessary, vibrated prior to matrix curing so as to force the fibers to approach geodesic trajectories (isotensoid layout). By releasing the sleeve tension after curing, a favorable compressive prestress is induced in the matrix material. Tension levels in the sleeves can be designed such as to produce a compressive transverse (interlaminar) normal stress component in the matrix thereby enhancing the shell resistance to delamination. A composite shell shaped by statical means may be used as a mandrel for subsequent filament winding and remain a permanent core of the final shell.
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